Reconstructing the substance gruit: an experiment

As part of the Experimental Archaeology Conference EAC12 hosted by EXARC this spring, I ran a handful of gruit experiments. Many gruit-beer experiments concern themselves with flavor and herbal components. They do not consider how or why the gruit substance may contribute to a longer shelf life, nor the reason its reputation as an essential element in brewing persisted for centuries even after hops came into common use. The consistent occurrence of grain in the surviving medieval tax records indicates that the grain aspect of the malt could be considerably more important than previously thought.

My experiments examine how the gruit substance affects fermentation and alcohol content, and therefore shelf life, leading to greater economic possibilities. In this blog post I will show you behind the scenes, so to speak, and share with you a bit more context and explanation than I was able to squeeze into my 5-minute video poster presentation. The experiments do not discuss gruit in the modern obsession of brewing with whatever herb one can get their hands on; to capture the essence of terroir, preferably in defiance of the hops establishment. While being much fun in its own right, it is not a very historic practice. My interest is in the medieval product itself: the substance of gruit and its herbal additives, and how this relates to the increased economics of the produced beer.

Contrary to what many modern publications would like us to believe, the historical sources are quite persistent that gruit is something more than just a collection of regionally unique herbs. A closer look at the etymology of the word gruit indicates an intimate connection with malt, in the form of coarsely ground grain. Even with variable medieval spelling, the different variants of the word are consistent with each other, and mean either the substance gruit, the beer brewed with it, coarsely ground grain, and the porridge made with such. Several Latin deeds use the words frumentum and polenta to describe the substance gruit, both words indicating a grain product. (Doorman 1955, 72; Ebbing 1994, 26-27; Kieft 1964, 165; Verberg 2018, 69)

If Low Country gruit indeed consisted of a concentrated malt porridge fortified with preserving botanicals and possibly yeast-rich chaff, then this would also explain several other Latin terms associated with the gruit product. When concentrated malt is added to the wort at the time of pitching, the boost of fermentable sugars would significantly enhance yeast fermentation. This would result in visible fermentation signs, giving the impression the gruit caused the “ferment” to happen. This effect resulted in the term levarentur for gruit, which is the Latin for leaven, or rising, and is also used for leavened or risen bread. As the concentrated paste caramelizes during the cooking down, adding this concentrate could darken the color of the wort as well, as suggested with the term pigmentum. The increase in fermentable sugars would raise the alcohol by volume, which combined with the preserving herbs and postponed spoilage just long enough for local commerce to be possible.

Two of the term definitions — gruit from the Low Countries, and grout from the British Isles — are connected to brewing. In the case of Low Country gruit, its connection with herbal ingredients is undisputed, while its connection with malted grain is questioned. In the case of British grout, a partially fermented cooked malt extract used to strengthen wort, interestingly, its connection with malted grain is undisputed – it is a known yeast-malt concentrate. It is not clear whether herbs played a role in medieval production, but they are not mentioned in early-modern grout descriptions. (Dodoaeus 1644, 813; Karkeek 1877, 196-97; Verberg 2018, 52)

If the substance of gruit indeed consisted of two parts – something produced with malt and heating equipment, and a combination of preservative botanicals – then it would stand to reason the malt portion is comparable to the malt product of British grout. And while there are no medieval recipes or process descriptions for medieval gruit, we are lucky with a couple post-period instructions for a similar product with a shared background.

I had located three publications which shared recipes on how to make grout. (Know of any others? Please share!) The 17th century publication quotes the 16th century source, and all three are about British grout. This is not unexpected, as by the 16th century, although in some areas the taxation is still active, the production and sale of the gruit substance had just about died out without a trace.

The first to publish a recipe for grout is the Dutch botanist Matthias l’Obel, also known as Lobelius, in his herbal Kruydtboeck oft beschrijvinghe van allerleye ghewassen, kruyderen, hesteren ende gheboomten First published in 1551, the edition that is freely available today, and from which I quote, is from 1581.

Graut wordt aldus ghemaeckt. Neemt ses of acht ponden ghemalen Mouts / siende heet water xij. oft xv. pont / de welcke tsaemen gheroert en wel onder een ghemengt zijnde ses mael sdaeghs / en met cleedere en stroo zeer we ghedeckt zijnde soo langhe tsaemen in een schoon vat sal staen weycken tot dat soo dicke wordt als een syroop. Daer nae salt voorts metten viere opghesoden worden / alleneen zeer neerstich roerende op dat niet aen en berne / tot dat soo dicke als pap gheworden is.” Graut is made thus. Take six or eight pounds of ground malt / seething hot water 12 to 15 pounds / the which is stirred together and is well mixed six times a day / and with cloths and straw well covered, shall soak so long in a barrel until it becomes thick as syrup. After that shall it quickly be heated with fire/ only stir very well as that it does not burn / until it is as thick as porridge.

L’Obel 1581

This recipe is reiterated by another Dutch herbalist, Rembert Dodoens (latinized as Rembertus Dodonaeus) in his herbal Herbarius oft Cruydt-Boeck. The 1554 edition titled the Cruijdeboeckonly lists botanical detail, which in the 1644 edition is updated and expanded upon to include product history as well as the occasional practical recipes.

Graut of Naerbier wordt aldus ghemaeckt / seyde Lobel: Neemt sex of acht ponden gemalen Mouts / twaelf oft vijftien ponded siedende heet water: Roert dit tsamen wel onder een / zes mael daegs: Decket seer well met cleederen ende stroo: ende laetet tsamen soo lange in een schoon vat staen weycken tot dattet soo dick wort als eenen Stroop. Daer nae suldij dat voorts metten viere opsieden / alleen seer naerstich roerende / op dat niet aen een berne / to dattet soo dick als pap geworden is.” Graut or Naerbier is made thus / said Lobel: Take six or eight pounds of ground malt / twelve or fifteen pounds seething hot water: Mix this together well / six times a day: Cover it very well with cloths and straw: and let it soak together for so long in a clean barrel that is becomes as thick as a syrup. After that cook it up again with fire / only stir very well / as that it does not burn / until it becomes as thick as porridge.

Dodonaeus 1644, page 813

A much later version, associated with the infamous White Ale, is published by Samuel Gray in The Operative Chemist (1828):

“Pale ale wort 25 gall, hops 2 handfuls, yeast 3lb, grouts 6 or 8lb. When the fermentation is at its height, bottle in strong stone half pints, well corked and wired; it effervesces when opened. The grouts here mentioned are made by infusing 6 or 8lb of malt in a gallon and a half of water, covering it warm by the fire side, stirring it often: when in full fermentation it is to be boiled down to a thick paste.”

Gray 1828

The etymology of the British word grout is very similar to that for continental gruit, and points back to the shared Latin term grut. It is entirely possible British grout and Low Country gruit shared common ancestry, but evolved separately. But how likely it would be for the two products, used in a similar way, to deviate so much, so quickly, is debatable. It is more likely the two shared more than their names, their use as additive in brewing, their reputation of a potent ferment – they probably also shared their base ingredient: the grain. Dutch historian Irsigler came to a similar conclusion: “What is certain is that a porridge was prepared from the various basic ingredients, especially from bog myrtle, ground malt, laurel berries and laserwort, which was heated, and then dried again.” (Alberts 2017, 52; Dodoaeus 1644, 813; Ebbing 1994, 29-30; Hornsey 2003, 530; Irsigler 1973, 84; Verberg 2018, 58-59)

With this in mind, I choose to run a small experiment and brew three interpretations of gruit to test several variables:

  • Could the gruit paste and gruit porridge, as instructed by the post-period recipes, adequately emulate the medieval gruit substance descriptions?
  • Does the addition of this gruit paste or porridge significantly change the specific gravity (SG) of the wort and thus the resulting alcohol by volume (ABV)?
  • Does gruit-porridge & syrup wort sour less quickly than the herbed, and/or plain wort?

For this I needed four samples:

  • Sample 1: plain wort
  • Sample 2: wort, plus the herbal & resin additive
  • Sample 3: wort, plus a malt syrup with the herbal & resin additives
  • Sample 4: wort, plus a grain-in malt porridge, with the herbal & resin additives

The wort was made by diluting a can of brewing malt extract to a SG of 1.05 (as advised for the brewing of standard 5% beer) and dividing the resulting wort over 4 one-gallon glass carboys.

I used a bread yeast as the more period-appropriate kveik starter was delayed in activation (our wood heated house might be too cold for its liking).

Producing the gruit substance

Version one:
Taking inspiration from the above-mentioned recipes, in specific the one by Lobelius (1554), I devised the following process for the first trial gruit: the porridge.

Process: Add 8 lbs of ground malt and 1.5 gallon of boiling water to my copper brewing kettle. Cover well, stir often, for a day. The next day, place on wood fired stove and slowly cook down to a thick porridge. Stir well to prevent burning.

Result: This indeed produces a sticky, dry porridge. It caramelizes well but is difficult not to burn at the bottom. It is easy to incorporate the crushed dry herbs and heated resin.

Version two:
As none of the recipes indicate whether the mash would be lautered (the liquid wort is filtered off the spent grains) and the wording is ambiguous (is it a syrup, or a porridge), I opted to make two versions, a grain-in and a filtered extract. The recipe for the porridge version did not generate much liquid, so for the syrup version I slightly tweaked the liquid volume to make sure there would be enough volume to concentrate (as the instructions do not suggest to sparge). The additives added later were adjusted accordingly.

Process: Add 6 lbs of ground malt (contained within a brew-bag) and 15 lbs (nearly 1.5 gallon) boiling water to the copper brewing kettle. Cover well, stir often, for a day. The next day, remove the brew-bag and thereby the grains (in lieu of a lauter tun). Place the kettle and the drained wort on the wood fired stove, and slowly cook this down to the consistency of syrup.

Result: This process produced a beautiful thick caramelized syrup. The evaporation did not require a lot of attention (unlike version one) and anyone with experience making jams and maple syrup will have no trouble recreating this. Be aware that hot syrup is more liquid than syrup at room temperature, without experience one could be tempted to overcook and burn.

The herbal additives

As suggested by the medieval gruithuis purchase accounts, I used the following herbs in the herbal mixture:

  • Bog myrtle; leaves and catkins
  • Laurel berries
  • Caraway (substituted for the unavailable laserwort)
  • Pine resin (colophon)

There are nearly no records available for the specific amounts of these herbs and spices in the gruit mixture. The one post-period recipe for Gruytbier uses very small amounts of herbs, and no malt (it does mention chaff; a gruit grain alternative, and something for another experiment).

“Om Gruyt, ende Gruytbier te maken. Neemt tegen eenen pot een koren bakelaer, ende alsoo veel aipoys, ende wat haveren doppen, ende twee saykens van gagel. Ende maeckt dit bier alleen van gherstenmoute, ende set dit dan met ghiste.” To make gruit and gruit beer. Take against one pot (half a gallon) a laurel berry, and also much resin, and some oat bran, and two seeds of bog myrtle. And make this beer only of barley malt, and set it with yeast.

The gruithuis accounts seem to indicate bog myrtle to be used most, and that laserwort was the most expensive ingredient. Modern science found that 2 grams per liter would inhibit lactobacillus souring (introduced 20 minutes before flame-out). Bog myrtle can have an overpowering flavor. The amount of herbs is adjusted according to the amount of malt used for the base gruit.

Gruit 1 (porridge) adjuncts: 30 grams of bog myrtle (20 gr leaves and 10 gr catkins), 30 gr of laurel berries and 5 gr of caraway seeds; as well as 42.5 gr (1.5 oz) of distilled pine resin. The herbs were crushed using a mortar and pestle.

Gruit 2 (paste) adjuncts: 22.5 gr of bog myrtle (15/7.5), 22.5 gr of laurel berries and 3.75 gr of caraway; 42.5 gr (1.5 oz) of distilled pine resin. The herbs were crushed using a mortar and pestle.

The four fermentation vessels are started as follows:

  • Wort 1 (porridge) includes a half gallon of plain wort, fortified with 9 ounces of gruit porridge.
  • Wort 2 (paste) includes a half gallon of plain wort, fortified with 4.25 ounces of gruit paste.
  • Wort 3 (herbed) was fortified with 3.75 gr of bog myrtle (2.5/1.25), 3.75 gr of laurel berries, and 0.6 gr of caraway seeds; 5 gr (? oz) of distilled pine resin. The herbs were crushed using a mortar and pestle.
  • Wort 4 (plain tester) is not fortified.

The carboys are capped with airlocks filled with star-san which will create bubbles to indicate active fermentation. They are then placed on a heating mat and wrapped with a blanket as the ideal fermentation temperature for bread yeast is 70-80 F (21-27 C).

At regular intervals, the specific gravity (SG) of the wort was tested. The addition of the gruit paste and porridge significantly raised the amounts of sugars in solution, raising the specific gravity and thus the alcohol by volume (ABV). The addition of extra sugars to a grain wort is also found in Farmhouse brewing, and is thought to have originated with the brewing with oats instead of barley. Oats do not saccharify as efficiently as barley and wheat, and to still make a strong beer, the Farmhouse brewers would add extra sugars. Oats are easier to grow, and in much of the Low Countries oats were the norm.

The table below indicates the starting or original gravity of the four different wort samples, as well as the final gravity reading at three weeks. The alcohol by volume is calculated as follows: (FG – OG) x 131.25 = ABV % The readings of the herbed and plain samples are identical, as expected, while the porridge levels are slightly higher than the paste. This is likely due to the spent grains not being sparged, or rinsed.

      Original Gravity               Final Gravity              ABV %
Porridge                      1.068                           1.024               5.775%
Paste                            1.062                           1.026               4.725%
Herbed                        1.052                           1.020               4.2%
Plain                            1.052                           1.020               4.2%

The readings of this proof-of-concept experiment indicates that, yes, adding gruit paste makes for a stronger beer. This supports the theory that the gruit substance positively affects fermentation including alcohol content and thus shelf life, leading to greater economic possibilities.

Question: If the shelf life of the brew is extended, either through raising the ABV % or by adding preservative herbs, can this be tasted in the resulting brew? How fast do the different samples sour?

  • Day 1: Pitched the yeast.
  • Day 6: all samples are effervescent, and sweet.
  • Day 12: The plain sample went sour (badly).
  • Day 16: The herbed sample is going (nicely) sour.
  • Day 20: The two gruit paste/resinated samples are still going strong, but unclear if this is due to the increased ABV or the potent resin.

Question: Can chaff (grain hulls) function as a source of spontaneous fermentation?

My experiment was not able to answer this specific question at this time as the local mill used to source fresh chaff in the past was closed to walk-ins due to the pandemic. But: the significant difference in the ABV % between the porridge (which includes the naturally yeasty chaff) and syrup might indicate there is validity to this: instead of providing active yeast, perhaps the chaff provides yeast nutrients and promotes vigorous fermentation. Happy yeast results in a quicker and potentially higher sugar to alcohol conversion. English grout uses dead yeast for a similar purpose.

Unanticipated Question: Does resin alone have a noticeable preservative effect, does the manner how it is added to the gruit paste matter?

The gruit syrup had a slightly higher amount of resin than the porridge due to oversight (did not account for the 2lbs difference between the two). The syrup brew stopped showing signs of active fermentation (bubbles) within a few days, unlike the other two, and it also tasted much more resiny (an unpleasant, antiseptic, mouth numbing taste). The heated liquid resin was poured into all three samples, but unlike my previous brewing with resin experiences where it was added to room temperature wort, it now was added to hot porridge and syrup as well. Presumably, the resin dissolved much more completely, dispersed much more finely, which significantly enhanced its preservative effect, as well as its unusual flavor. The resin flavor, while initially very sharp, did mellow out over time (now, two months later, it still has not soured and while it does not drink well, it does work great as a cooking beer).

The addition of herbs to plain wort somewhat slowed down the souring process. The addition of grain paste to raise the SG slowed down souring even more, and the use of resin boosts this protection further. Concentrating gruit porridge takes more effort to prevent burning than concentrating into syrup, but unexpectedly, the benefits of a higher OG (no wort lost by removing the spent grains) and possible yeast nutrients could make up for this inconvenience. The addition of resin might be more important in connection to the preservative function of gruit than previously assumed.

Food Drinks for thought…
That the ABV percentage would be higher after adding concentrated malt (gruit paste) was assumed, but the difference is more significant than initially expected. Porridge gruit could be a viable option: syrup seemed to be the obvious choice but the experiment seems to indicate porridge to be more efficient. The difference in application between adding hot resin to cold substrate as opposed to adding hot resin to hot substrate is significant. The unexpected effect seems reminiscent of my wax comb mead experiments, where the hot wax dispersed into the wort but did not re-solidify when cooled, and further investigation is warranted.

Poster presentation at the Experimental Archaeology Conference #EAC12, Wednesday March 31st, Session 12. After the presentations follows a one-hour live session with Questions & Answers. Please Join us.

Overview of Session 12:


  • Alberts, Leen. 2017. Brouwen aan de Eem: Amersfoort, een Stichtse bierstad in de late middeleeuwen. Hilversum: Uitgeverij Verloren.
  • Arnold, John P. 1911. Origin and History of Beer and Brewing. Reprint Edition 2005. Cleveland, Ohio: Beer Books.
  • Dodonaeus, Rembertus (Rembert Doedesz Joenckema). 1644. Herbarius oft Cruydt-Boeck. Leiden: Inde Plantijnsche Druckerije van Francoys van Ravelingen. Plantaardigheden.
  • Doorman, G. 1955. De Middeleeuwse Brouwerij en de Gruit. (The Mediaeval Brewery and the Gruit). Den Haag: Martinus Nijhoff.
  • Ebbing, Hans. 1994. Gruytgeld ende Hoppenbier. Een onderzoek naar de samenstelling van de gruit en de opkomst van de Hollandse bierbrouwerij van circa 1000-1500. Doctoraalscriptie middeleeuwse geschiedenis. Amsterdam: Universiteit van Amsterdam.
  • Gray, Samuel Frederick. 1828.  The Operative Chemist. London: Hurst, Chance, and Co.
  • Hasselt, Gerard van. 1804. Arnhemsche oudheden, Volume 2. Arnhem: J. H. Moeleman Junior.
  • Hornsey, Ian Spencer. 2003. A History of Beer and Brewing. RSC Paperbacks. Cambridge: Royal Society of Chemistry.
  • Irsigler, Franz. 1973. “Hermann von Goch als Kölner Grutpächter.” In Aus Geschichte und Volkskunde von Stadt und Raum Bonn: Festschrift Josef Dietz zum 80. Geburtstag am 8. April 1973, ed. Edith Ennen and Dietrich Höroldt, 79-88. Bonn: Röhrscheid.
  • Karkeek, Paul Q. 1877. “White Ale.” Reports and Transactions of the Devonshire Association for the Advancement of Science, Literature and Art 9:188-197.
  • Kieft, C. van de. 1964. “Gruit en ban.” Tijdschrift voor de geschiedenis 77: 158-168.
  • Matthias Lobelius (l’Obel). Kruydtboeck oft beschrijvinghe van allerleye ghewassen, kruyderen, hesteren ende gheboomten. Christoffel Plantijn, 1581.
  • Schiller, Karl & Lübben, August. 1876. Mittelniederdeutsches Wörterbuch. Zweiter Band G-L. Bremen: Kühtmann’s Buchhandlung.
  • Runde, Justus F. 1788. Aus führliche Darstellung der gerechten Ansprüche des Grafen zu Bentheim Tecklenburg auf die Herrschaft Bedbur, gegen den Grafen von SalmReiferscheid.
  • Verberg, Susan. 2018. “The Rise and Fall of Gruit.” Brewery History Journal. 174: 46-78. ResearchGate.


Stig Seljeset and friends brew a traditional Hornindal kornøl as part of the Norsk Kornølfestival 2020

Saturday October 10th, which happened to be my birthday weekend, the brewing world was treated to a special event: the Norsk Kornølfestival 2020. First happening in 2016, the festival quickly grew a fine reputation for the place to be for anyone interested in farmhouse brewing and the phenomenon of raw ales. But as the brewing is demonstrated at actual farmhouses, and the festival location is more or less central to those, this means traveling to the Norwegian outback to be able to see first-hand what this living history tradition is all about. Then came 2020, and with it the opportunity to go virtual.

Session 1:
Session 2:

For a whopping 12 hours anyone interested could follow the brewing of three different styles of farmhouse beer at three different farmhouse locations. Lars Marius Garshol, of Larsblog fame, and Amund Polden Arnesen, brewer at Eik & Tid, hosted the slow-TV festival. When brewing activity would be minimal, viewers were treated to several talks of which only one was in Norwegian (thank you!). Mohammed Tawfeeq, from University of Leuven, talked about Traditional beers as a source of new yeast biodiversity, Mika Laitinen demonstrated the brewing of Finnish bread/beer taari and Martin Thibault looked Beyond Kveik at 3 Unexplored Hotspots for Heirloom Brewing Yeasts (all three in session 2). I was very sad to see Jereme Zimmerman was bested by the demons of virtual technology and never got his sound to work. Perhaps we’ll see, and hear!, him next year?

During these 12 hours, three farmhouse ales were brewed using three slightly different processes. Hornindal brewed a raw ale, Stjørdal a 1-hour boil ale, and Voss brewed a 4-hour boil ale. Each group of brewers did things in a slightly different way: as they said themselves, where you have 50 brewers, you will find 50 different methods, and each brewer thinks their beer is the best!

The different brewhouses did share the use of open fire and a copper kettle, as well as the use of locally grown dried hop flowers and fresh juniper sprigs. I spent a wonderful Saturday glued to the TV watching these different brewers chat about beer, while taking copious notes to fine-tune my own open-air medieval brewing demos. Videos of the live festival are released on youtube and to make navigating the two 6-hour YouTube videos a little less confusing, I will annotate each brew, step by step, as they appear in the videos (the times listed can be plus or minus a few seconds). First up is the raw ale by the brewing team at Hornindal.

Hornindal kornøl

Stig Seljeset and friends demonstrate the brewing of a traditional Hornindal kornøl. This is a raw ale, meaning the wort is not boiled, and is made with juniper infusion, fairly pale malts, noble hops and kveik. They work outdoors under a large pavilion and brew, of course, in a copper kettle over open fire. Stig uses a stick of juniper as a mash paddle and a stainless-steel saucepan for a scoop. The mash tun and lauter tun are both plastic barrels. The barrels seem smaller than standard US 55-gallon barrels but otherwise look quite similar – I am guessing a volume of about 35-40 gallons. The wort is drained into steel milk cans, and fermented indoors in another plastic barrel. The process is similar to the brewing description by Terje Raftevold in Historical Brewing Techniques (p. 283), as well as the Larsblog post “Brewing raw ale in Hornindal” (

12:40 (indicates the minutes:seconds of the video)

Hornindal gets going with a general introduction of the brewhouse and the brewers. The brewers present are Stig Seljeset (owner of keik #22 Stalljen; wearing a blue pullover), Olav Sverre Gausemel (ownder of kveik #18 Gausemel), Lars Andreas Tomasgård (ownder of kveik #21 Tomasgard), Odd Steljeset, brother of Stig and owner of the brewhouse, and Arve Raftevold as well as a number of other local brewers apparently looking to replenish their diminishing store of beer. There is a kettle with a juniper infusion steaming in the background. The festival started at noon local time and the brewers have had some time to start preparations. The juniper used in the infusion is picked fresh, with or without berries, and is not really measured. Stig prefers to harvest juniper tips from the small weedy shrubs, not their nice large ornamental trees. Some of the branches go in the water for the infusion and some go on the sieve bed.

Stig checks the density of the mash with his juniper stick.

44:30 – 50:07

Half an hour later they are ready for the mashing. The brewers pour some juniper infusion from the kettle to a large, blue plastic barrel, the mash tun, then add some dry crushed malt, followed by more infusion, and more malt. The infusion and the malt are added alternatively, for better dissolving and to prevent clumping, while the whole is vigorously stirred with the mash paddle, a stick of juniper. Stig gauges how much liquid to add by how much resistance the mash gives to the mash paddle. He tests this by standing the stick in the middle and looking at how fast it falls sideways: he’s looking for a slow-motion slide. When he is satisfied, they leave the mash for an hour, at least, before they do anything more. More water is added to the kettle to replace what was used during the mashing. When the mash tun is full they put something over top, an empty bag in this case, “so no birds etcetera would do anything in it, that would be not so good” and weigh it down with some wood.

1:25:51 – 1:36:50

While waiting for the mash to convert, Stig talks about how wooden equipment is hard to store and clean. In the 70’s they started using plastic and recently they started using stainless steel. He shows an old stainless-steel hot-water boiler with a spigot, with its top cut off and three feet welded to the bottom. The top can be flipped over and is used as a slotted filter and will sit on the inside, on top of the juniper sieve.

2:19:34 – 2:42:21

It is time for lautering the mash, or draining the liquid wort from the solid grain bed. For this they use a separate plastic barrel which has a spigot at the bottom, the lauter tun. It is partially filled, then raised off the ground before it gets too heavy. Hornindal uses a wooden tool to create draining space for the spigot, a U-shaped channel riddled with holes (further explained in the larsblog post linked above). This is called the rustesko (lauter tun shoe), and is placed in front of the tap, around which the juniper is tightly packed. It is important the juniper is placed just right so there are no big gaps and the grain does not plug the tap. They use several handfuls of short branches.

The rusteko, a home made lauter tun filter. For a better picture click here.

The mash is carefully added to the lauter tun so the juniper filter does not slip away. This is easier to do when the barrel is still on the floor and the inside of the barrel easily visible. Before it is too heavy, the lauter tun is lifted onto a stand (another barrel with a board over the top) so the spigot is at a higher level than the wort canisters.

When all the mash is scooped into the lauter tun, they are ready for tapping. One of them uses a juniper branch to sweep the remainder mash grains out of mash tun. They already have more, fresh juniper water ready in the kettle. The first 3 to 5 liters of wort are put back in again so all of the flour that comes out at the beginning is back on the top. They run the wort until it is clear, so the fine particulates that came out of the malt go back in. Now it is time to prepare the hops (Hornindal uses about 150 grams of amarillo), as well as getting ready for the kveik.

The hops are in a bag which hangs in the milk can, right under the spigot so the wort drains out of the lauter tun, through the hops bag, and into the milk cans. They do not have hops in the lauter tun. The brewer would taste the wort and when it gets too strong remove the hop bag, and if not, leave it in the whole time. All the wort is drained very slowly out of the lauter tun into the milk cans. The hot juniper infusion from the kettle is used to sparge. At the beginning of the lautering stage the brewer started a kveik bowl by drawing out some hot wort in a kveik bowl to cool it down. He uses a big glass bowl, no more than half full, as it will be put near the fire to keep warm.

“You are welcome to the beer.”

4:20:05 – 4:31:09

Stig placed the kveik bowl near the fire, guided by experience, and moves it closer or further away depending on the temperature. Hornindal shows a beautiful traditional kveik bowl with the text “you are welcome to the beer” around the rim in which the dried kveik flakes are stored. When the kveik wort reaches 29C, they usually look for between 28-32/34C, the kveik flakes are shaken into this wort. A bit cooler does not matter too much right now, but when added to the beer wort it should be 30-32C as then it would start to ferment quicker.

They are tapping into their second milk can as they can still taste the sweetness. The brewer explains: “We don’t measure the sweetness with anything else than we just taste it, that is the traditional way, and that is why we are still doing it. We don’t measure everything with modern technology, we use the way they did hundreds of years ago – so it’s traditional, all the way.” He changed the hop bag from one container to the other, and squeezed it a bit.

Hornindal does not use a standard wort chiller, a coil of copper tubing and garden hose, but something they came up with themselves: a perforated garden-hose collar around the neck of the milk can, which leaks cold water all around the sides of the metal can to cool down the wort. They might do this as a standard copper coil would not fit in the milk can as the opening is relatively small. The first can of wort was about 36-37C when poured into the fermenter (in the garage, this happened off-screen), which is a bit too warm for the kveik. He thinks it is better to start a little too warm, than too cold; the process takes a little while and otherwise it needs to be warmed back up. He opts for cooling down the second milk can a bit to make up for the difference.

About half a dozen brewers are drinking beer in the background, kveikøl from different brewers, but they were all almost empty so they have been patiently waiting for this day for a couple of weeks now!

5:23:36 – 5:36:06

Hornindal is congratulating the kveik, locally called the “mariaue,” as it has “really done a good job, it is all foamy.” The kveik starter is 32C and they are ready to put it all in the “jeel,” here the fermenter. They normally have the fermenter in the basement as it is warmer there, but they found they have no video down there so for the sake of the festival the “jeel” is set up in the garage. The fermenter needed some insulation as otherwise the kveik would not be warm enough.

And then it is time for the Yeast Scream! [5:27:30]

“We have done the brewing, now it is up to the kveik to do the rest of the job. We have to wait 40 to 48 hours and then we will know how it is.”

It is time to clean up the mess, to have dinner, and then a party!

Hornindal leaves the fermenter open while fermenting, sometimes covered with a blanket but not usually. In summer they might use a lid because of bugs, but not usually.

To brew traditional Hornindal kornøl


  • open fire
  • copper kettle (circa 150 liters)
  • plastic barrel mash tun
  • plastic barrel lauter tun
  • plastic barrel fermenter
  • metal milk cans to store & cool wort
  • thermometer
  • home-made wood filter block
  • home-made wort chiller


  • 100% lager/pilsner Norwegian malt
  • homegrown juniper
  • Amarillo hops
  • house kveik.


  • The brewers start by boiling a juniper infusion in the copper kettle.
  • Then add this infusion with the malt, in small amounts, to the mash tun. The mash is stirred very well, covered, and let sit for an hour. The water in the kettle is replenished to heat and be ready for sparging.
  • The lauter tun is prepared by placing the wood filter block in front of the spigot and packing it tightly with juniper branches.
  • The mash from mash tun is carefully scooped around and on top of the filter block and juniper in lauter tun. Then the lauter tun is lifted onto a platform and the rest of the mash is schooped in, with a scoop, by hand. The first 3-5 liters of drawn wort is added back to the lauter tun, not until the wort runs clear is it collected in the milk cans.
  • Some of the first wort is drawn off for the kveik and cooled; at the same time they make a hops bag and hang this in the opening of the milk can, under draining wort.
  • When the wort reaches between 28-32C the dried kveik flakes are added. This needs to be done as soon as possible to give the kveik several hours to start proofing.
  • The wort is very slowly drained through hops bag into milk can, this takes about 2 hours.
  • Start sparging by adding hot juniper water on top of the mash in the lauter tun. This pushes out any remainder wort and rinses the grain bed of any remainder sugars.
  • When the wort loses sweetness, they stop sparging and pour wort into an (indoor) insulated fermenter. It will likely need to be cool down, for which they used their home-made wort chiller.
  • Pitch kveik – and do not forget to SCREAM!
  • Clean-up, dinner & a party.

The introduction of the Brew #1: Hornindal team:

The YouTube screen grabs are used with permission from the festival organizers.

Gruit contains bog myrtle, marsh rosemary – and yarrow?

One of the better-known historic beers, gruit beer might just as well be also the one most misunderstood. The importance of gruit beer within the socio-economic and political structure of medieval Europe meant much is written about the taxation system surrounding gruit. But the product gruit did not receive much attention, at least not until very recent times (see my publication “The Rise and Fall of Gruit”). Gruit beer is enjoying a resurgence as an alternative to hopped beers. This craft beer revival has many brewers taking a closer look at recreating historic beers, including gruit beer. What they will find is the idea that the identity of Low Country gruit is unclear and unlikely to ever be solved. But that the best guess is that the herbs used were bog myrtle, marsh rosemary – and yarrow. And no matter how hard I look, I cannot find an “historical link” between gruit and yarrow.

To be clear, this story is about historic gruit beer, not modern gruit ale which can use any type of botanical additive as long as it is not hops. Historic gruit beer is much more narrowly defined, mostly using the same three kinds of herbs, pine resin and a grain product. There are many websites discussing modern gruit ale, but only a few talk about historic gruit beer. Alexandre Bessette of says the following on the historic gruit beer ingredients:

Bessette: “Gruit ale is historically linked with these 3 herbs. Delicious and satisfying beers can be brewed from either of these on their own, but a true gruit will usually contains all three.”

The three main herbs used in historic gruit beer are bog myrtle or marsh rosemary, laurel berries and laserwort. The data from nine different gruit brewing city accounts show these purchases consistently and without much variation. But those are not the three herbs Bessette referred to: he meant bog myrtle, as well as marsh rosemary – and yarrow. Bessette is mentioned by Richard Unger in his article “Gruit and the preservation of beer in the Middle Ages” and he said about Bessette’s work on reviving the interest in a drink made with that combination that:

Unger: “… he is performing a valuable service in creating a range of experiments which set out to create something like the medieval drink. His own experience harvesting bog myrtle, yarrow and marsh rosemary in eastern Quebec to create a marketable gruit have yielded information about the process of creating what he and many others conclude is the additive. His posting of various recipes ad requests for reports on what brewers found when they have made various forms of herbal beer has already expanded the range of experimental archaeology.”

Kevin Cullen, an experimental archaeologist from the Discovery World in Milwaukee, Wisconsin, was involved in a similar brewing experiment as part of the “Ale Through the Ages” brewing seminar hosted in 2011. Cullen brewed a Belgian Gruit Ale based on the same three botanicals as Bessette mentioned, as well as juniper.

Cullen: “The three most common herbs were Bog Myrtle (Miricia gale), Yarrow (Achillea milleflolium) and Wild Rosemary (Ledum palustr).  Other later gruit additions often included: Cardamom, Caraway, Ginger, etc. Therefore, this all-grain recipe is true to the pre-14th Century Belgian Gruit style, which combined bog myrtle, yarrow, wild rosemary and juniper berries.”

The mention of pre-14th century by Cullen reminded me of a collection of supposed historic beer recipes published in “Old British Beers Book” by beer historian John Harrison, member of the Durden Park Beer Circle which he may or may not have been aware of. It lists two “Gruit Ale (ca. 1300)” recipes which, to the common brewer, seem to suggest they are based on an actual historical recipe. Both recipes again advise using bog myrtle, marsh rosemary and yarrow. They reference to Jeffrey Patton’s “Additives in Beer: Adulterants and Contaminants.” As Patton does not list any recipes, presumably Harrison’s recipes are his best guesses based on Patton’s information, not on any literal recipe (and this makes sense, as the grain bill is modern). Patton, again, reiterates the same three botanicals.

Patton: “The three major ingredients of gruit were:
1. Myrica gale, also known as sweet gale, pors, porze or porst.
2. Ledum palustre, also known as marsh or wild rosemary.
3. Achillea millefolium, also known as milfoil or yarrow.”

He does not cite his information but his bibliography shows he is familiar with Corran (1975) and Arnold (1911). He goes on to say the composition did vary from region to region and refers to the 1393 Cologne accounts, which list similar alternative herbal ingredients as Cullen mentioned. This is correct, but only partially, as from all the city accounts that survived the years, only the Cologne accounts suggests botanical variety.

But first, let’s take a closer look at the botanicals. Why these three? The first two, bog myrtle and marsh rosemary are easy. They are both found in the city accounts although there is a bit of a trick as both marsh rosemary and bog myrtle are known as pors. The properties and function of the two plants is so similar that they could be used interchangeably. It seems that the gruit producers bought bog myrtle and marsh rosemary at trade markets but that the two were not traded long-distance. Bog myrtle and marsh rosemary grow in mostly separate habitats with marsh rosemary more northern (circumpolar). This means the Belgium and Dutch regions of the Low Countries would use native bog myrtle, and the northern German region would use native marsh rosemary. Both bog myrtle and marsh rosemary were gruit ingredients, but not as two separate ingredients used in combination, in the way modern brewers envision.

The third ingredient, yarrow, is a bit of a mystery. So, what about the cardamom, caraway, ginger and juniper berries as mentioned by Cullen? The connection with cardamom is a bit unclear, but caraway, ginger and juniper come from the 1391/93 city accounts from Cologne, Germany. The accounts list the purchases of caraway, cumin, anise and juniper, as well as the actually common gruit ingredient laurel berries and bog myrtle of course (ginger is a likely mistranslation of juniper). What they also list are two ingredients they apparently wanted, but did not have: the laserwort and resin.

Laserwort is part of the plant family Apiaceae, as are caraway, cumin and anise, and juniper could potentially stand in for the missing resin. It looks like the gruit producer in Cologne was trying his best to emulate the product of his peers. Even though he used different ingredients, apparently he wanted his product to fit in, not stand out. He was not alone in this sentiment. By 1408, the gruit from Neuss was thought to be “much better than that from Cologne.” So… how “gruit” are these ingredients? If the brewer preferred the standard bunch, and the locals preferred the gruit from somewhere else, then my guess is not so much.

backyard yarrow

Then again, what about the yarrow? I am not sure. Out of the city accounts of nine Dutch and German cities spanning from 1339 to 1530, not a single one mentions yarrow. The accounts do consistently mention bog myrtle, marsh rosemary (but only for Munster and Wesel), laurel berries, laserwort, resin and some sort of grain product, in the form of malt, flour or chaff. If the information in the city accounts does not match the description of gruit found in popular publications, are modern publications consistently reprinting misinformation?

According to Ann Hagen in her expansive tome “Anglo-Saxon Food and Drink” (1992/2010), yarrow is found in connection with Anglo-Saxon English brewing. Odd Nordland in his well-researched “Brewing and Beer Traditions in Norway” (1969) found that yarrow, although not as often as bog myrtle by far, was part of Nordic historic brewing. But as gruit was only brewed in the Low Countries, which covered what is now the Netherlands, Belgium, northern France and western Germany, this does not mean yarrow therefore was part of gruit. The assumption that the growing range of bog myrtle was synonymous with the production of gruit and gruit beer by for instance Richard Unger would explain why these sources are absorbed into the history of gruit. Or perhaps modern researchers also had trouble connecting yarrow with gruit, and went with the assumption that if neighboring countries would use it, then surely the Low Countries would too?

The Scandinavian author Nils von Hofsten, who wrote extensively on the use of herbs in Scandinavian brewing, believes the use of yarrow in gruit “is very questionable.” Mika Laitinen voices a similar sentiment in his “Viking Age Brew: The Craft of Brewing Sahti Farmhouse Ale”

Laitinen: “Many sources claim that yarrow (Achillea millefolium) was a typical constituent of gruit, but that is perhaps a misconception. I think the claim is rooted in another misconception, that the gruit region extended to the Nordic area.”

Tracking gruit – and in its wake, yarrow – through many publications I noticed an interesting pattern: the same books would show up in the bibliographies, books which perpetuated the connection of gruit and yarrow. Unfortunately, many of these books do not cite their sources (well) and several are dead ends. Hagen (2010) for instance referenced “A History of Brewing” by Corran (1975) but Corran does not cite his source.

Corran: “Before hopped beer became customary in German, a mixture of herbs, including bog myrtle, rosemary and yarrow, among others, was employed; this mixture was known as gruit, and the product as gruit beer.”

A bit more round-about, Harrison (1993) referenced Patton (1989) which has no references but does have a bibliography. Patton is familiar with both Corran and the “Origin and History of Beer and Brewing” by Arnold (1911) but unfortunately both Corran and Arnold are dead ends.

Arnold: “Opinions as to what went into the composition of gruit differed formerly, and even to-day, somewhat. However, to judge from the scan information that has come down to us at this point, it must have been chiefly three plants which formed the stock of the gruit, namely:

1. Myrica Gale, sweet gale, called in Westphalia Pors, Porze, Porst, and the same in Danish, as well as Swedish; well-known also in the moors and bogs of Scotland and elsewhere.
2. Ledum Palustre, marsh or wild rosemary, in German Sumpfporst, porst, wilder Rosmarin, Bienen-, Brauerkraut, also Wanzen- or Mottenkraut (moth or bug herb).
3. Achillea Millefolium, milfoil, yarrow; German Schafgarbe.”

Unger (2011) references “The Mediaeval Brewery and the gruit” by Doorman (1955), among others, and even though Doorman worked from primary sources and lists the correct herbal ingredients of bog myrtle, marsh rosemary, laurel berries, laserwort and resin., he also added yarrow. But without citation this is another dead-end. Doorman did list “Beer has a History” by Frank King (1947) in his bibliography, which might explain why he felt the need to add yarrow even though his historical sources do not support it.

King: “Gruit was a mixture of herbs which included sweet gall or bog-myrtle, marsh or wild rosemary, and yarrow or milfoil and probably other ingredients.”

Unger also cites “A History of Beer and Brewing” by Hornsey (2003), who in turn (probably) cites the dead-end Corran (1975). Before it gets too confusing, let’s put the most influential authors in order of publishing: Unger (2011), followed by Hornsey (2009), Buhner (1998), Hagen (1992), Harrison (1993), Corran (1975), Doorman (1955), King (1947) and finally Arnold (1911). It seems that most of the English language popular publications refer back to either Corran or Arnold. Neither Corran nor Arnold left any hint of where they themselves came across the information.

Without having anything more to go on, for now, Arnold (1911) is as far back I’ve been able to track the use of yarrow in Low Country gruit. I had high hopes for John Bickerdyke’s “The Curiosities of Ale & Beer: An Entertaining History” (1889) but it does not mention gruit (or yarrow) at all. Perhaps the gruit/yarrow connection originated in a non-English source? It is a non-English drink, so that would make sense. Either way, I am rather impressed by how solidly this one ingredient attached itself to the history of gruit and will definitely keep an eye out for any new leads. Whomever first wrote down the idea must have presented it with gusto for it to have become such a solid fact.

My question to you, the reader: do you have any old and obscure brewing books on your physical or virtual book shelves? Can you take a look and see what is to be found in there? I just know Arnold is citing from another source, and wouldn’t it be cool if together we could find out from where. Proost!


  • Arnold, John P. 1911. Origin and History of Beer and Brewing. Reprint Edition 2005. Cleveland, Ohio: Beer Books.
  • Bessette, Alexandre.
  • Buhner, Stephen Harrod. 1998. Sacred Herbal and Healing Beers. Boulder, Colorado: Brewers Publications.
  • Corran, H. S. 1975. A history of brewing. David and Charles.
  • Cullen, Kevin.
  • Doorman, G. 1955. De Middeleeuwse Brouwerij en de Gruit. (The Mediaeval Brewery and the gruit). Den Haag: Martinus Nijhoff.
  • Hagen, Ann. 2010. Anglo-Saxon Food and Drink. Combined version of: A handbook of Anglo-Saxon food: processing and consumption, published in 1992, and A second handbook of Anglo-Saxon food & drink: production & distribution, published in 1995. Hockwold cum Wilton, Norfolk, England: Anglo-Saxon Books.
  • Harrison, John. 1993. Old British Beers and How to Make Them. Durden Park Beer Circle.
  • Hofsten, Nils von. 1960. Pors och andra Humleersättningar och ölkryddor i äldre tider (Bog Myrtle (Myrica gale) and Other Substitutes for Hops in Former Times). Acta Academie Regie Gustavi Adolphi Vol. 36. Copenhaven: Lundequistska Bokhandeln.
  • Hornsey, Ian Spencer. 2003. A History of Beer and Brewing. Royal Society of Chemistry. Cambridge, UK: RSC Paperbacks. Academia.
  • Laitinen, Mika. 2019. Viking Age Brew: The Craft of Brewing Sahti Farmhouse Ale. Chicago: Chicago Review Press.
  • Nordland, Odd. 1969. Brewing and Beer Traditions in Norway. The Norwegian Brewery Association, Universiteitsforlaget. Norway: Mariendals Boktrykkeri A/S.
  • Patton, Jeffrey. 1989. Additives in Beer: Adulterants and Contaminants. Exeter, Great Britain: Patton publications.
  • Unger, Richard W. 2011. “Gruit and the preservation of beer in the middle ages.” Special Topic Issue: Medieval Brewing. AVISTA Forum Journal. 22: 1/2: 48-54
  • Verberg, Susan. 2018. “The Rise and Fall of Gruit.” Brewery History Journal. The Brewery History Society 174: 46-78. ResearchGate.

How Viking is mead, exactly?

Anyone thinking of Vikings also thinks of mead, the two seem inextricably linked. It should seem surprising to then find that there was basically no local honey production in Norway and most of Sweden before the middle of the 18th century, and even after, access to honey was extremely limited. Maybe the reason mead is mentioned so often in the Saga’s is because it was such a rarity – was it truly only a drink for kings and the Gods? The earliest recorded account of the production of mead in connection with the Northern lands is in the Historia de Gentibus Septentrionalibus (History of the Northern People – 1555) by Olaus Magnus – Archbishop-in-exile of Uppsala, as at that time Sweden was not Catholic anymore. During his exile Olaus Magnus wrote extensively about his home lands, including a chapter with instructions on making mead. He then added two chapters on making Polish, Lithuanian and Goth mead. As this broadly overlaps with the trading areas of the Viking era one wonders if most of the mead consumed by the Vikings was imported from down south, way down south. Another early cookbook with mead recipes of the Scandinavian region is the Danish Kogebog (1616), which literally means cookbook. It includes two chapters on mead, with much practical information including which herbs work well to spice the mead, and the numerous health benefits of mead. It is clear mead was made by the Danish, but then, even though Denmark is part of Scandinavia it is geographically connected to Germany, not the Scandinavian peninsula, and much more southern and more hospitable to beekeeping.

Magnus-BookXIII OCR-9

From Chapter 23 of Olaus Magnus: “On the voluntary drowning of King Hunding in mead or hydromel.”

And that is the crux of the matter: looking closer at the geographical setting of the Northern lands as compared to the geographical distribution of bees shows something interesting. Scandinavia lies just on the cusp on the natural range of honey bees. The south of Sweden and Denmark are within the native distribution of honey bees, but their natural range ends just south of Norway. This excludes central and northern Sweden and near all of Norway from local honey production, although theoretically, honey bees might survive in the south-eastern corner, right around Oslo and down along a little way on the western side of the Oslo fjord. The reason for this is not the cold, as one might assume, but the short duration of the flowering season. Honey bees collect pollen and nectar from flowering plants, which is their food. They concentrate nectar into honey as an emergency food supply for the hive, among other uses. As the flowering season that far up north is too short, the bees run out of honey and starve to death before the next season begins.

Chased by Suttungr, Odin spits the mead of poetry into several vessels. Some of it accidentally goes out the other end. Illustration by Jakob Sigurðsson, an 18th-century Icelandic artist. (Public Domain)

If that is the case, then why is mead so often mentioned in the Norse mythologies? Maybe it truly was a matter of wishful thinking. There is less mention of mead in the sagas, which claim to be stories about actual people. One of these mentions from Egil’s saga recounts of someone sailing to Denmark to buy honey, as well as other things, which makes sense if there was no local beekeeping. There are other mentions, but on average it seems real people mostly drank milk products and beer. Surviving records show wine was considered the best by the Norse, with records of wine traded from the Mediterranean up to Scandinavia back to the year zero, then mead, likely imported either as honey or fermented, and then locally-produced beer (coincidentally, or maybe not, this is the same order in which Olaus Magnus has listed his wine, mead and beer descriptions and recipes). True to human nature, it was not the easily available product which was considered finest – after all, it is always that which is hard to get which is valued above all others.

But: there does seem to be one caveat in dealing with Viking age beekeeping from a modern point of view. Much of the Viking era coincided with the Medieval Warm Period, which happened from about 950 to 1250 CE. It is conceivable beekeeping was possible then, even if only in an opportunistic wild beehive robbing sort of way. Eva Crane’s World History of Beekeeping and Honey Hunting recounts of a find of “tens of thousands” of dead bees from 1175-1225 CE in the Old Town of Oslo, which could mean purposeful beekeeping. Or it could be a singular large hive which died spectacularly all over the town, as one hive can contain from 10,000 to 60,000 individuals. But it is feasible people did keep bees in at least part of Norway during that time, and later lost the knowledge when the climate changed again, and the northern lands became too hostile for bees. More likely is that local beekeeping never was very widespread, but as the famous traders and raiders the Vikings were known for, they bought and plundered honey from abroad.

The popularity of mead waned in the rest of medieval Europe as the production of honey slowed and prices rose and the consumption of beer spread. When The Medieval Warm Period was followed by The Little Ice Age, lasting from about 1350 to about 1850, this also contributed to the decline of medieval honey production, especially in short season climates like northern Europe and southern Scandinavia. And with the increase of population and thus agriculture, old growth forests which provided nectar were cut down and wild flower meadows were planted with grains, which yield no nectar at all. By the 14th century a gallon of French wine was cheaper than the honey needed to make a gallon of mead, and by the 17th century imports of cheap sugar from the West Indies mostly replaced the use of honey in cooking and brewing. Mead survived well into the 18th century in central Europe, where raw materials were easy to get from the large forests they still had, and in the rest of Europe in different versions as a drink for the sick. It could well be that mead did not only decline because of cost, or the improving quality of other drinks, it could also be because mead was said to be so good for the drinker’s health, it became associated with the sick and the weak.

Example of sheltered beekeeping from the European Alps (left –, in which individual hive boxes are communally housed within a larger structure to help the hives make it through the winter cold. Another concept for Viking Age appropriate hives, similar to log hives as found in illuminated Medieval manuscripts (right –

Whether or not the Vikings were active beekeepers, from the numerous mentions of mead-drinking in the Saga’s we know they sure enjoyed the results, or at least wished they could. Surprisingly, it took until the middle of the 18th century for someone to figure out how to keep bees successfully in the Oslo area. He did this by closing down his hive with a perforated screen in early spring to prevent the bees from flying and feeding the bees watered down honey. That far up north, the bees run out of honey and wake up too early in spring to go in search of flowers while there still is snow on the ground. They go in search of food because they are starving, and instead freeze to death. Keeping them cooped up and fed they can be kept alive until the rest of nature wakes up and there is food for them to find – the similar as our modern practice of feeding sugar water. From that point on, beekeeping spread, and resulted in a strong tradition of beekeeping, especially in the south-eastern corner of Norway and southern Sweden, that grew into a local mead-making tradition.

Much of this information comes from an ethnographic survey on farmhouse brewing issued by the Norwegian Ethnographical Research Institute (NEG) in 1952 and 1957. This questionnaire ran 103 questions, and questions 99 to 103 dealt with mead, and the results were surprisingly consistent: most of Norway at that time had no mead-making and barely any mead drinking tradition at all – except for a small cluster south of Oslo, and down into southern Sweden. Of the small handful of Norwegian responses, one replied people collected wild honey, and four replied independently that people who kept bees sold the honey, but then made mead from the honey that remained stuck to the wax combs. The beekeepers would dissolve the honey in hot water, boil it, add some spices, and then ferment it. A process very similar to the washed comb mead making techniques found in medieval cook books.


Modern beekeeping in Sweden, from Biodlingsföretagarna, the Swedish Professional Beekeepers website (


  • Crane, Eva. The World History of Beekeeping and Honey Hunting. Taylor & Francis, 1999.
  • Garshol, Lars Marius. Norwegian Ethnological Research. Posted in Beer on 2014-09-15 15:38
  • Garshol, Lars Marius. Mead: a Norwegian tradition? Posted in Beer on 2018-04-15 12:16
  • Gayre, Robert. Wassail! In Mazers of Mead. Colorado, US: Brewers Publications, 1986.
  • Husberg, Erik. Honung, vax och mjöd : biodlingen i Sverige under medeltid och 1500-tal.
  • Unger, Richard W. Beer in the Middle Ages and the Renaissance. Philadelphia, PA: University of Pennsylvania Press, 2004.

Medieval Gruit Beer at Homebrew Con 2019

I presented my first seminar at the 2019 Homebrew Con in Providence, RI, this weekend:

Medieval Gruit Beer Reconstructed: New Theories on Old Beverages.

Gruit as a product changed throughout its history. From a beer additive revered for its fermenting powers, it evolved into a beer with a reputation for powerful headache-causing herbals. The exact nature of gruit was once thought to be lost, but available sources paint an interesting picture of gruit, not just as a handful of brewing herbs, but as a powerful and necessary wort fortifier. Although not all puzzle pieces have been uncovered and gruit’s exact nature can’t yet be described, several theories adequately corroborate known facts.

Poster presentation for the 2019 Homebrew Con:

Presentation Poster Gruit

Iron Age stone brewing demonstration

My interest in anything Viking age, and anything early-period brewing merged last weekend when I organized a brewing demo at a local medieval festival. Jeff Boerger traveled from afar to help Ken Stuart and I work our way through the different steps of successfully brewing an all-grain beer with nothing modern but a thermometer – and honestly, we did not even truly need that! Inspired by a Facebook post by a Texan brewer who shared his interpretation of an Iron Age brew in northern continental Europe around 2,000 years ago that he brews for an Iron Age immersion week each spring, I figured we could give it a try too.

While 2,000 years ago is a wee bit past the Viking age, it is unlikely the way of brewing changed all that much from the Iron age until Middle age monastic breweries started pushing the boundaries of brewing volume and shelf-life. And while there might not be a whole lot of recorded history, with only a single example from the Icelandic Ljósvetninga saga telling of milk warmed by stones, there is plenty of archaeological evidence for the brewing of beer in Viking age context. Residues of a fruit & honey beer from northwest Denmark of circa 1500-1300 BCE, found in 2014, included honey, bog cranberry, lingonberry, bog myrtle, yarrow, juniper, birch tree resin, as well as wheat, barley and/or rye. And there is nothing archaeologist like better than rubbish heaps and trash middens, of which the old farmsteads have plenty!

It seems in central Norway the rubbish heaps suggests Vikings and their descendants brewed beer by tossing hot rocks into wooden tuns. Many a fire-cracked stone is found at most of the farmyards of old, historically named farms. Unfortunately for the archaeologists, since most archaeological digs are initiated by construction sites, as developers are required to check for cultural artifacts before beginning construction, most construction sites avoid developing through a farmstead. This means most of the archaeological information we have about the Viking age comes from graves, and most of the archaeological information about the Middle ages comes from excavations in cities – which misses a large chunk of data as most people back then lived in the countryside. Recent small-scale excavations in farmyards found that the oldest farmsteads carbon-14 date to 600 CE, the late Iron age.


Nineteenth century Sociologist Eilert Sundt recorded an encounter on a farm in 1851 in Hedmark, Norway after seeing a pile of strange looking smallish stones. “What’s with these stones?” he asked and the farmer replied “They’re brewing stones. Stones they used for cooking to brew beer, from the old days when they did not have iron pots.” Sundt noted that most of the farms he visited had piles of burned or fire-cracked stones, and every time he asked about them, he was told the stones were from brewing, when they would be heated until they were glowing hot and plopped into the wood vessel to heat things up. The stones were everywhere, Sundt wrote, and so thick and compact in places, houses were built right on top of them! A modern excavation at Ranheim, near Trondheim, Norway, found 700 cubic meters of stones from just one portion of the farmstead. A test sample of 24 farms found that 71 percent had fire-cracked stones. Hot rock brewing would not be as obvious in the archaeological record elsewhere as with Norwegian brewing stones because of the types of stones used, as most regions use stones which tolerate heat without fracturing, like the igneous rock granite and basalt. Brewing beer with hot rocks is nothing unusual, and traces of brewing with stones have been found in England, Germany, Finland and the Baltics.

And thus, in the great tradition of Gulating’s law – the Gulating being the Norwegian governmental assembly which met from 900 to 1300 CE – requiring three farmers to work together to brew beer, Jeff, Ken and I set up our brewing along gorgeous Cayuga Lake to make some Viking beer!

Our grainbill:

  • 18 lbs of 2 row barley malt
  • 4 lbs of malted oats
  • 1 lb of acidified barley malt
  • ½ lb of peat smoked barley malt (very smoky, use sparingly)
  • ½ lb of malted rye (left over)

The grain was milled on-site, and by hand.

With an infusion of:

  • Yarrow (big handful)
  • Baby spruce tips (handful)
  • Mugwort (less than a dozen sprigs)
  • Henbit (small handful)
  • Aged, yellowed hops (handful)

The herbs were fresh and picked the day before. The hops are homegrown and have been sitting in the dark in my basement for about a year. This way the brew gets minimal flavor, while still benefiting of some of the preserving qualities.

Step by step how we made our stone beer:

First thing we did was start a fire to make the coal bed.

Then we used that fire to make a juniper infusion and clean out the wood tub (the mash tun) with the scalding infusion to clean and sterilize.


Then we put a layer of juniper twigs covering the bottom, concentrating around the plug (there is hole in the bottom of the mash tun, kept closed with the plugging stick).

We milled the grains by hand: we used 2 row barley, malted oats and some random leftovers, including rye, as well as some peat smoked malt.


Then we added water. We added it cold from the tap – it could also be pre-heated in the sun, especially in summer.

Next, we put stones on the coal bed and built another fire right over top of them, with a hardwood / pine mix I had brought from home to make sure we had dry wood.

IMG_0810 - Copy

In the traditional Scandinavian style, we made a separate tea, or infusion, with the herbal bittering agents. We used yarrow, some mugwort, aged and yellowed hops, some henbit, and baby spruce tips.

When the fire was mostly burned down again, we started pulling stones, and added them to mash (the soaked grains) 3 or 4 at a time. Jeff really enjoyed this bit, as did my son when we did a water-only trial in the back yard. We tried three metal grabbers and found the funky accordion style firewood grabber worked best.

We kept checking the temperature, especially the top and bottom as the mash & juniper was quite insulating and there often was quite a heat difference between the top and the bottom. It was difficult to stir with the juniper branches covering the bottom. At around 130F we observed protein break which made the surface of the mash all foam up.

We kept adding hot rocks until overall temps were at or over 160° F, and then we kept it at this level for an hour and a half – adding more stones as needed.


By now, whenever a new hot rock is added, the wort (the liquid surrounding the grains) surrounding the rock immediately went to a boil, creating lots of steam, a wonderful smell of sweet malt, lots of sizzling & sputtering, and quite the surface boil. This part, which takes about an hour and a half, is spectacular to watch!

At around the end of the protein rest (the hour and a half) we noticed the protein foam had dissipated, and the wort started to settle. So, we put the draining bucket under hole, carefully wiggled the plug stick, and slowly drained the wort into a sterile bucket. I would plug the drain back up each time the bucket was ready to dump the filtered wort into a sterilized fermenter bucket. This traditional way of having a combined mash tun (where the grains are soaked) and a lauter tun (where the infusion is drained off the grains) worked surprisingly well.

We sparged with boiling water. We intended to use juniper water but ran out of cooking vessels as we started to cook dinner while waiting for the protein rest. We drained about 4 gallons from the initial wort, and another 2 gallons were sparged, by trickling boiling water over the mash to wash out any remainder sweetness. The last sparge we handed around for anyone to taste.

We made about 8 gallons of wort from about 25 pounds of grain, including 4 pounds of oats I sprouted and roasted (called malting) over the winter, and bittering adjuncts grown and harvested from the backyard. All in all, it took about 6 hours from start to finish, but we also took all the time we wanted and ended up cooking dinner over the hot stone fire as well – rabbit with spring onions, over barley, nettle and plantain. It was a good day, and I can’t wait to taste the results!

The things we learned:

  • Making the first coal bed took a while. In case of restricted time start with a bag or two of charcoal, add rocks, and built a wood fire over that.
  • We needed more pots to boil water, and/or vessels to store juniper tea for sparging.
  • Stones crack, but slowly, crumbly, and pose no danger (apart from sharp edges when fishing them back out of the wort). It is no wonder the farmyards had layer upon layer of discarded stones, as from two trials I already have half a bucket of small gravel! Brewing stone beer means keeping an eye out for replacement granite.
  • When the wort reached about 130° F, we saw foam (protein break). When it reached about 160 °F the surface was really steaming (and too hot to touch easily). When it had sat for about the right amount of time, the foam had also started to dissipate and the wort was starting to clear.

Back home, I added some Nottingham dry ale yeast, and Ken added Munton’s “Active Brewing Yeast” which the package says “…is a high viability robust yeast carefully selected for its consistency and clean finish.” As we had brewed on an alcohol-free Boy Scout campground I had not brought any yeast to pitch on site. When we tried the wort at about the 5-day point, we found it to be more acerbic and herbal tasting than expected. It had soured, quite likely because of the delay in pitching our yeast. The little bit of wort I had added to my yeast ring did not sour, but was fairly bitter, like an overly hoppy IPA. I checked back in with the Iron age brewer and he suggested not to boil the herbs, but only to steep, and to add the infused tea as a sparge, not during heating. We will do further testing before our next demonstration and look forward to sharing our results with you then! Skål!

For anyone who would like to try Cy Phorg’s Iron Age interpretation:

  • 4 lbs of 2 row barley malt OR a mix of light and dark Munich malt
  • 1 lb of rye malt
  • ½ lb of peat smoked malt
  • ¼ lb acid barley malt

Mash for 160° F or more for 1.5 hours

Steep in ½ a gallon of water a combination of:

  • Juniper branch tips (handful)
  • Meadowsweet (several handfuls)
  • Sweet gale
  • Heather (handful)
  • Henbit / deadnettle (handful)
  • Yarrow

All preferably harvested in spring, use with flowers and buds when possible. Sparge with the herbal tea first.

Cy uses kveik yeasts, farmhouse/saisson style yeasts, and Belgian/Trappist style yeasts to good effect, often in a mixture and often with a health addition of bread yeast. It will be ready to drink in as little as 48 hours, though in his experience he finds 72 hours is a good spot to start pouring. It is not intended to be carbonated, and should be consumed in a day or two.

More on brewing with stones:

Blaand – Seeing Whey in a New Old Way

Historic Scandinavian cuisine has a few unusual techniques and flavors otherwise seldom found in European cooking, such as the infamous lye preserved lutefisk, the caramelized whey cheese gjetost and whey preserved vegetables and meats. After tasting some fabulous whey preserved salmon chunks, I wanted to learn more about the process – how was it done, and especially, why did it work? And I found that in the age before refrigeration, foodstuffs were preserved in many different ways, mostly using dehumidifying (drying, salting, smoking), altering the pH (acidic or alkaline pickling / fermentation) and introducing antimicrobial alcohol (alcoholic fermentation) – or any combination of the above – all creating an environment unpleasant for spoilage bacteria.

Learning more about whey preserved vegetables and meats (acidic pickling) lead to an intriguing website claiming alcoholic fermented whey had come to Scotland by way of the Vikings, which piqued my interest. According to this website, blaand (var. bland, blaund) was made by fermenting whey with a sugar source, and it was touted as a traditional Viking / Scandinavian drink. Looking deeper into caramelized whey-cheese gjetost I had found that it was a fairly recent invention, from around the introduction of refrigeration, and that before whey was such a commodity to help preserve the harvest it generally was not used for much else. Which made me wonder, if caramelized whey gjetost is a more recent invention, then what about fermented whey blaand?


In the Orkhon valley, mare’s milk is fermented to make airag, a potent alcoholic drink, and turned into a variety of snacks. (Photo: Scott Presly / Flickr, 2012: CC BY 2.0)

With the domestication of animals to provide a regular supply of milk, meat and other by-products like leather, bone and horn, certain cultures also developed a type of fermented beverage different from the traditional fermentation of grains, fruits and honey. The consumption of animal milk is thought to date to the mid-6th millennium BCE, or maybe even earlier.  Because of the in-between step of domestication, fermented-milk beverages were generally developed at a later date than traditional grain, fruit and honey ferments, the latter not even needing human intervention to occur. Archaeological evidence suggests fermented milk beverages have been known for millennia, and likely originated in the Middle East and the Balkans. Kefir and kumis are the best-known examples of fermented alcoholic milk drinks, and are made with certain strains of lactic acid bacteria and yeast. Numerous species of lactic acid bacteria, yeasts and molds can be involved, making the microflora of milk fermentation fairly complex and not always predictable. Alcoholic drinks produced with yeast & lactic fermentation are often of white or yellowish color, have a slightly yeast-like aroma, a somewhat tart and refreshing taste, and are often of a thick consistency. (Rasmussen 2014, 71-76)


Vendor of Koumis, Fermented Mare’s Milk poured from a leather bag, in front of the shrine Aulie-Ata in Syr Darya Oblast. Taken between 1865 and 1872 (Public domain).

Kumis is an ancient beverage traditionally made from mare’s milk. On average, mare’s milk contains 6.4% lactose by weight, which is about 30% higher than that of cow’s milk. Because of the higher sugar content, kumis generally ferments out with a higher alcohol content than kefir, varying from 0.6 to 2.5%, or similar to the small beer tradition of Western Europe. Both kefir and kumis carbonate, but where kefir is started from kefir grains (granular cultures), kumis is started from liquid starter culture including various thermophilic lactobacilli. A number of fermented beverages modified from kumis have been produced by various cultures and are often made with other animal milks. (Rasmussen 2014, 71-76). Sometimes kumis is distilled to make the much-stronger Mongolian arkhi, which has a 12% alcohol content.


Cheese curds & whey. (Photo: Cecilia / Flickr, 2010; CC-BY-2.0)

While kumis is produced from whole milk, blaand is made from whey, a by-product from the curdling process of milk which makes for instance cheese and yoghurt. Described as the national beverage of Iceland and the Faroe Islands, this whey-like liquor is a modification from traditional kumis, also indicated with whey-kumis as opposed to proper kumis (from milk). As proper kumis contains all the casein of the milk, it is much more nutritious than the whey based blaand. (Jagielski 1872, 124-125)

Occasionally, whey drinks are mentioned in literary sources, but the sources are sparse, and the mentions short. For instance, blaand is found in two Scottish newspapers, once as part of a larger article written as a travelogue (1928), and once as an interesting fact (1884), as well as in a travel account from 1774.  Penelope’s Notebook, a column of interesting facts printed as part of the Aberdeen Press and Journal in Aberdeenshire, Scotland published Wednesday June 27, 1928 had the following to say on blaand:

 “A common drink with the people of Shetland is called blaand. Sour buttermilk is stood over a gentle heat until the whey separates from the curds. This whey is the blaand. It is either drunk in a fresh state or stored away till it has fermented. Fermented blaand sparkles, but after a time it becomes flat and is not so good. This, however, can be remedied by adding new blaand as required. It is a refreshing drink in warm weather.”

The Dundee People’s Journal from Angus, Scotland published on Saturday January 19, 1884 an installment of a longer story following the exploits of Arthur and Osla, incidentally giving us a good description on how Scottish blaand was made in the late 19th century:

”I thought blaan was a sort of drink,” said Arthur. “I’m sure I’ve heard old William Raemusson talking about it.” “That’s blaand,” said Osla, “which is quite a different thing. Blaand is – father, please tell Mr Carew how blaand is made.” “Blaand is hot water poured upon the remains of the butter milk left in the churn. This precipitates the cheesy part of the milk, which is then lifted out; and then the whey and the water that remain are allowed to rest till they ferment, when the liquor becomes as clear as spring water and acquires an agreeable acid taste. This is blaand. They say the Icelanders have a drink like it. But I never was there, and I cannot tell.”

Joseph Anderson recounted in his “A Tour through the Islands of Orkney and Shetland” from 1774 the following:

“Bland, or the serum of Buttermilk separated by heat, is much used as a drink, kept till it is old and sharp, but I should think it dangerous, causing colics, and all kinds of gripes.”

Interestingly, while all accounts agree on the source of blaand being whey, it seems not to matter how the whey is produced. It can be alcohol-fermented (which would make it sparkle), or not, and while a connection with Iceland is established it seems that whey-kumis blaand is traditional to parts of the British Isles, not Scandinavia, nor the Vikings. If that is the case, then where does the Viking connection come from?

According to the Oxford English Dictionary the earliest occurrence of the word ‘bland’ in this context is in 1703 regarding the drinking of bland in Shetland.  And the entry for 1821 quotes: “She filled a small wooden quaigh from an earthen pitcher which contained bland, a subacid liquor made out of the serous part of the milk.” Another dictionary which could be helpful because of the connection with Scotland is the Dictionary of the Scots Language (Dictionar o the Scots Leid).

  • BLAND, Blaand, Blaund, n. and v. [bl?(:)nd]
  • (1) Whey mixed with water, a drink used in the Shetland Islands. Given for Sh. by Edm. Gl. (1866), Jak. (1908), Angus Gl. (1914) s.v. blaand. Sh. 1774 G. Low Tour thro’ Ork. and Sh. (1879) 104:
  • Bland, or the serum of Buttermilk separated by heat, is much used as a drink. Sh. 1914 J. M. E. Saxby in Old-Lore Misc., Ork., Sh., etc. VII. ii. 70:
  • Blaund, whey of buttermilk. The whey is allowed to reach the fermenting, sparkling stage. Beyond that it becomes flat and vinegary. “Soor blaund” is a delicious and quenching drink, and used to be in every cottage for common use. It is what fashionable doctors recommend for consumptives under the name of the “sour whey cure.” Ork. 1929 Marw.:

The Dictionary of the Scots Language also lists the earliest occurrence of the word ‘blanda’ in its second definition of meaning a mixture of two fluids, especially sour whey mixed with water, dated to 1604 from a quote of the Sh. Sheriff court. And it notes the etymology, the heritage, of the word blaand as derived from the Old Norse blanda (feminine), a mixture of fluids, spec. ‘a beverage of hot whey mixed with water.’ This word matches the description of the Nordic Cleasy-Vigbusson entry of the Germanic Lexicon Project: blanda, any mixture of two fluids; but esp. a beverage of hot whey mixed up with water. It looks like a whey drink, called blanda, was known in the Nordic lands, but the etymological information does not confirm whether it was alcohol-fermented, like whey-kumis, or only acid-fermented. Norwegian farmhouse brewer Lars Marius Garshol knows only of blanda (var. blande) as sour whey mixed with water, without any alcoholic fermentation – the whey was left to sour in huge wooden vats and as it became too sour to drink it was then mixed with water before consumption. According to Garshol, it was the everyday drink in Norway, but much less so in Sweden. The acidic fermentation of the lactobacilli in the whey would, when mixed back in with surface water, sterilize possibly contaminated water and create a safe, inexpensive drink for everyday use.

Take note of the entry under ‘blanda’ in the Cleasy-Vigbusson: it also lists ‘mjöð bland’ which one could interpret as whey mead, but unfortunately means generic mead-mixing (derived from mjaðar bland). The earliest dated Scandinavian mention of blande as a beverage seems to be in the Natural History of Norway, written by Bishop Erik Pontoppidan in 1752-53. He writes that Norwegian peasants used to drink blande, made by mixing milk and water, or in winter, water and sour whey. The peasants’ wives boiled sour whey to preserve it through the summer as a beverage. (Fosså 2000, 147)


James, from Happy Homestead, Orkney, UK brewing Blaand wine with whey and sugar, and living the allure of anything Viking.

Then where does the prevalent idea that blaand is a Viking whey wine, made from sour whey, a sugar source and yeast come from, as perpetuated by sites like the Orkney Happy Homestead and Wikipedia? It does look like the Vikings might have had an acidic fermented water & whey drink called blanda, but it was unlikely to be alcohol fermented. The Scottish did have an acidic & alcoholic fermented whey beverage called blaand, but while likely related, the two do not seem to have mixed (no pun intended). Another ingredient connected to blaand which does not come up in any of the historic and etymological material is the addition of another source of sugar to the whey, to boost alcoholic fermentation. That might be a more recent addition, as our modern tastes enjoy the sweet & sour taste, as well as a higher alcohol level. In history, sugars were a valuable commodity and used sparingly. It was not until cane sugar became farmed large scale in the West Indies that sugar moved from being stored, together with the valuable spices, under lock and key to become, with the spices, a staple of everyday life. In regards to the Viking connection one should also note that there was basically no honey production in Norway and most of Sweden before the 1750’s, and even after that access to honey was extremely limited.

Apart from boosting the fermentable sugars to raise the alcohol by volume (ABV) levels, another reason to ferment modern blaand with an additional sugar source could be that whey contains the complex sugar lactose. Ordinary brewer’s yeast Saccharomyces cerevisiae does not easily convert complex sugar into alcohol and needs a hand to help break down the lactose into galactose and sucrose, which then it can convert. (IFIC) This is why dried lactose can be used as a sweetener in beer and wine, as the yeast will ignore it. Successful open-air fermentation could capture microorganisms such as Kluveromyces lactis or Kluveromyces fragilis that can convert lactose to alcohol. (Yang) There is a strain of S. cerevisiae that can ferment lactose, the infamous Saccharomyces cerevisiae var. diastaticus but this strain should be used with extreme caution as it is very virulent and once it takes hold in a brewery, it is very hard to eradicate. (Chai) Historically, this might not be as problematic for breweries dedicated to the fermentation of whey – traditional breweries often brewed at the most a handful of similar brews utilizing the house-yeast strain that colonized their structure, inadvertently creating place-specific yeast strains with unique flavor and character (and the basis of our modern day yeast libraries). But contamination is most definitely a problem for modern-day brewers, and luckily, we can circumvent the problematic yeast and add digestive enzyme lactase directly (conveniently available at the drug store) to convert the lactose after which it can be fermented with a traditional brewer’s yeast.


The Longboat’s Landing Party Whey Wine by Sean Bailey at the Fat Friars meadery, from cow’s milk whey and fermented with honey and lactase (

Another more recent invention to ferment with whey is the production of whey beer. Whey is a bulk by-product of strained yogurt production – 10 pounds of milk makes one pound of cheese and 9 pounds of whey (Yang) – and thus creates quite a disposal challenge for the dairy industry. As sour beers are gaining popularity, sour whey beer, which already is sour to start with, could be the next big thing. The idea behind sour whey beer is that barley contains enzymes capable of breaking down lactose into galactose and glucose, which can then be fermented by brewer’s yeast S. cerevisiae. Acid whey typically has a pH <4.5, a lactose content of 3.0 to 3.5%, and calcium content greater than 1.2 mg/g. Experiments by Professor Samuel Alcaine of the Food Science Department at Cornell University showed that lactose hydrolysis using a raw barley mash did indeed raise the levels of fermentable glucose of the mash. In the production of sour beers, acid whey can thus potentially act as a natural acid as well as a fermentable sugar source. (Lawton 2019)

What is often thought of as a problematic waste product requiring a high energy intake to commercially process into whey protein powder, turns out to also have wonderfully useful incarnations, especially in history as well as in our modern times. Perhaps, next time you make cheese and yogurt, put some of the left-over whey back into the container and stick it in the fridge until it clears and make a Viking blanda. Add some lactase, and let it wild-ferment for a bit and see if you can make a Scottish blaand. My favorite is fresh whey generously topped off with concentrated syrup, or honey, which will spontaneously ferment if left alone. Throughout history, whey has always been seen as a nutritious resource worth exploring. Even now, with our myriad choices of beverages – fermented, and not – it is exciting to experiment with something different: why not brew some refreshing whey wine, or sour whey beer!



Conference Review: REARC 2018

The 8th annual Reconstructive and Experimental Archaeology Conference hosted by EXARC drew speakers and participants from many parts of the world. The REARC conference was once again hosted by Colonial Williamsburg in Virginia, from October 18th to the 20th. Friday was reserved for the presentation of papers, by students and researchers alike, demonstrating the wealth of information and practical skills available within the EXARC community. Saturday was filled with numerous demonstrations in which the conference attendees could participate and museum visitors could watch and learn.


My presentation Of Boyling and Seething (Photo S. Stull).

The presented papers ranged from practical recreations like bird bone flute making and weaving reed beads to duplicate pottery impressions, to the use of recreated objects, such as determining if Ötzi’s tools were for hunting or for warfare, and the function of experimental archaeology within different types of classrooms. Some researchers presented a follow up on previous papers, like Neil Peterson with his ongoing Viking bead furnace project. Some might look for resources not yet found – the joy of Caitlin Gaffney after finding a possible source for a reproduction medieval knife to carve her bone flutes was absolutely contagious. And some were looking to network: David Spence asked for additional projects for his Experimental Archaeology in High School and left with numerous contacts and suggestions. Each and every paper had some unique view, some unusual bit of information – as the practical aspects of experimental archaeology requires a more interdisciplinary approach than traditional academics, conferences like REARC are essential. You just never know from what discipline, from which subject, the answer to the question you did not even realize you had could come from. I personally was amazed to find that the gist of my paper, to not take words at their literal modern definition, was independently repeated in another paper – to have my initial interpretation validated via an independent source right then and there.


Bill Schindler, experimental archaeologist and co-host of the National Geographic show The Great Human Race. I enjoyed our conversation over a craft beer at the hotel, and even taught him a thing or two about historic mead brewing.

The keynote speaker for this year was Bill Schindler, an experimental archaeologist with Washington College and part of the Eastern Shore Food Labs. His quite engaging presentation on Fusion: ancestral diets, modern culinary techniques, and experimental archaeology was well received, and left the audience with a number of questions to think on. This paper was perfect for our younger generation, our students, as they are now growing up in an environment which might be more hostile to them than they would surmise, and where their chosen area of research, experimental archaeology, could help shed light on where to go from here. The connection between human biology and our diet, and the impact industrialization has had on our health to the point where humans, and our pets, can be both obese and malnourished, is not only fascinating from an academic point of view, but pertinent to the survival of our species.


This years’ demonstrations were two part: the practice of throwing atlatl and observing and shooting early bows, combined with the technique of smelting tin and casting bronze and making Viking era glass beads. Unfortunately, while the weather was absolutely gorgeous on Friday, by the time Saturday came around it had changed to intermittent drizzle and rain. But that did not stop us from having a go at each of the stations, and appreciate the added value of tent coverings at the metallurgy and flamework areas. While I would have loved to try Ötzi’s replica bow as initially intended, Manuel Lizarralde did not feel comfortable to have it out in soaking rain as it was not yet waterproof. I did get to shoot a fire hardened black locust Native American self bow, weatherproofed with bear grease, and even hit the target center. Conference host Tim Messner enjoyed the primitive tattoo kit and extant stone tools the Native American interpreter brought to share – and almost talked him into a tattoo demo on the spot.


Fergus Milton, with help from David Spence, melting bronze to do a lost-wax mold casting later in the afternoon

At the station near the Blacksmith area we enjoyed Fergus Milton’s bronze casting demonstrations – with help on the bellows by David Spence – using a small furnace constructed on site from local clay, and aerated with a primitive leather-bag bellows. He began the day by smelting the bronze and preparing two molds, and poured the molds mid-afternoon. Several museum guests returned specifically to witness the casting, after stopping by periodically to keep an eye on the proceedings.


Making a glass Viking bead while Neil works the bellows (Photo by S. Stull).

At the same time Neil Peterson had his coal-fed bead furnace up and running for conference attendees to try their hand at making a Viking glass bead. His station was in continuous use throughout the day and many of the attendees left with a precious homemade bead in their pocket. Surprisingly, participants often had more trouble with the coordination required to operate the bellows effectively, than they had creating a simple bead.


To cap off this wonderful experience, the resident founders at Williamsburg had invited Fergus Milton for a special bronze casting demonstration Sunday morning at their shop. To experience the prehistoric process, so closely followed by the much more refined methods of the 18th century Geddy Foundry, was an appropriate ending to an otherwise perfect immersive weekend of reconstructive and experimental archaeology. We are ready to come back for more next year!


All photos credited to Susan Verberg, unless otherwise stated.

For details on the presented papers:

Reprinted at:


How gruit is a koyt beer, really?

The Dutch language has a saying I have not found an English equivalent for: hearing the bell toll, but not quite knowing where the clapper hangs. It kinda-sorta means “close, but no cigar” and I was reminded of just this during our trip to the Netherlands this summer when we visited the craft brewery Jopen and I ordered one of their historic brews: Koyt Gruitbier.


A nice glass of gruited koyt at the Jopen Brewery in Haarlem, the Netherlands..

I had found out about this beer as part of my research into the early medieval Dutch beer called gruit and was quite curious to see, and taste, this commercial interpretation up close. And my first question upon seeing the label was: why is it called a koyt gruitbier? I asked a resident brewer and the answer was that they used the grainbill for koyt and added bog myrtle seeds (and other undisclosed herbs…) for gruit, to make a historic gruit beer.

To understand why this is historically problematic, and rather ironic to boot, let’s take a look at the beer style koyt, modernly known as kuit. The Jopen Brewery is located in the city of Haarlem in the province of North Holland – a city with a long brewing tradition going right back to the middle ages. To distinguish themselves from other craft brewers Jopen Brewery delved into the archives of their city for inspiration and the lucky bastards located several beer recipes to help start their brewing business. They chose to redact two recipes for commercial production, a 1407 recipe for koyt and a 1501 recipe for (generic) hopped beer. Of course the brewery was not amenable to sharing its sources, but lucky for us, the city archive is open to anyone and following are scans of the original 1407 koyt recipe and the 1501 hopped beer recipe.

Brouwerskeur 1407 (05)-37coyt

Also those who want to brew coyt, they shall brew in the brew barrel no hopped beer within four days, that is to understand, that three or four days would be in between, having brewed with hopped beer. And as well one shall to each brew coyt brew with 12 eightparts wheat malt, eighteen eightparts barley malt and four and twenty eightparts oats malt and of each not less, on the fine of 3 pounds.

This information, combined with the following ordinance about water usage, gives a good idea of a recipe for medieval koyt.

Brouwerskeur 1407 (05)-38coyt

About coyt, which one transports over sea, one shall not brew longer than 26 barrels, on the fine of 3 pounds, and about coyt which is sold domestically, and one shall not brew longer than 25 barrels coyt, and of each not more, or less, of one wants, also fined as regulated.

But wait, there is something missing… what about the hops? And that’s where part of the confusion originated: these ordinances are not recipes, they are grainbills. Hops, and in earlier times the additive gruit, was under its own taxation and was not mentioned in the ordinances, not even in the 1501 Haarlem ordinance for hopped beer (displayed below).

Full page photo

Also it is ordained as well, that a decent brewer or brewster who wants to brew hop beer, in each brew hop beer dumps ten eightparts wheat malt, and thirty-six eightparts oats malt, and thus so may each brewer or brewster exchange, if they want, for each sack wheat malt two sacks spelt malt or sacks of barley malt, and that until three sacks wheat malt and not more, and thus so shall one brew each hop beer brew fourteen stucken and a half long and not longer, that is to say fourteen stucks to deliver and to keep a half stuck for their drinkebeer (small beer), and that one shall not squeeze or push [press] nor brew on a loose bottom, and so who does different, there is the fine of 12 crowns and no work, until one shall have paid as above.

The burghemasters and the court consented, that a decent brewer or brewster may brew hops as well on a loose bottom as differently, and that without a fine.

Was it because of mistaking grainbills for recipes that for decades there was a persistent misunderstanding between kuit (koyt) and gruit (gruyt) beer? Or maybe because the two names sound so alike it was assumed the beers must be alike, or even the same. So how do we know if koyt really was made with hops, and not gruit, as Jopen Brewery assumes? The answer to that question is actually two-fold. Historic mentions of koyt beer outside of brewing ordinances indicate a clear connection between koyt beer and hops. For instance, the Duke of Burgundy licensed in the year 1455, in favor of the Goudsche (from Gouda) brewers, the hops-taxation on their brew: Goudsche Kuyt.[i] Another brewer’s regulation of 1460 mentions hops-taxation clerks can fine delinquent brewers of large beer and coyten.[ii] And the History of the city of Gouda from 1817 explains in the 1520 description of brewing “no herb except for hops” was allowed in their brew.[iii] But even more important in the gruit-versus-hops debate in connection with koyt are their respective time-lines.

In the early middle Ages in large parts of the Low Countries, which consisted of modern Flanders, the Netherlands and parts of Germany, the production of commercial beer was taxed through the sale of a product thought necessary to ferment a proper beer, called gruit. The sale of this grain-and-specific-herb-product made a number of families very rich, and then a new method of brewing appeared on the horizon. Not only was this beer, made with hops, able to travel and thus be traded – it did not fall under the gruit taxation! This new hopped beer from the Hansen city-states in not-quite-yet Germany, like the rotbier made in the city of Hamburg, scared the pants of the gruit masters and import of this beer, and of hops, was quickly banned. Of course, the Holland citizens – as the Netherlands did not quite yet exist either – recognizing a good thing, were not that easily persuaded. By 1321 the sale and production of hopped beer was officially permitted – and taxed (initially often under the umbrella of gruit). By 1327 Haarlem started the production of hopped beer, as well as Dordrecht in 1322 and Delft in 1326, quickly out-competing the traditional gruit ale in the provinces of North and South Holland. [iv] For some reason the southern parts of the Low Countries persisted in making gruit ale over hopped beer for another 100 years or so – which could probably spawn a quick joke or two about those people from below the rivers, but let’s keep on track.


The brewing kettles, flanked by bar and stained glass windows…

Back to Jopen Koyt Gruitbier – a beautiful beer brewed in a beautiful church and touted as a real historic beer. Which it is, although more correctly: it is two historic beer styles rolled into one. This commercially successful beer illustrates the importance of knowing your history. As we’ve seen, Koyt and gruit beer did both exist in medieval the Netherlands, and both at the same time, but not in the same regions. By the early 15th century, in the region of northern Holland, gruit ale had already disappeared – outcompeted by the very successful imports of Hamburg beer that were quickly locally produced, and exported, under the name of, wait for it… koyt.

Basically, Jopen Brewery attempted to make a historic gruit, and based it on the beer that had killed it.[v] That’s irony.

On the other hand, a brewery named for a well-known historic beer type but states on its website the name is inspired by a beer barrel size historians are not familiar with, might need a sprinkle or two of extra salt when reading their folklore – I meant history. Although, I nearly reached my breaking point with the following description: “Jopen Koyt is brewed with gruit, a medieval blend of herbs in which sweet gale picked according to ritual was essential. Legend has it that, to avoid its hallucinogenic properties, sweet gale could only be picked at full moon by nude witches.” I would love to see that reference – with illustrations.

The moral of this story? Do not believe everything you read on the internet. Just because someone is proficient in something does not mean they are proficient in everything. Remember, legend sells as Jopen’s gruitbier slogan shows: deliciously risky. The biggest irony? Jopen Brewery could have had three fantastic historic recipes. The Jopen brewer might not be a historian, but he does know how to brew: that gruit ale sure tasted like more!




[i] Brunel, etc. Groot algemeen historisch, geographisch, genealogisch, en oordeelkundig woordenboek, behelzende zo het voornaamste, dat vervat is in de woorden-boeken van Morery, Bayle, Buddeus, enz… Netherlands: De Companie Bookverkopers, 1725 (exerpt)

[ii] J. Jacobs. Korte chronycke van vele gedenckweerdige geschiedenissen: soo in de principaele steden van het hertoghdom van Brabant als in de stadt en provincie van Mechelen, Volume 1. Loven, the Netherlands: Joannes Jacobs, 1747. (exerpt)

[iii] Cornelis J. de Lange van Wijngaerden. Geschiedenis en Beschrijving der stad van der Goude: meest uit oorspronkelijke stukken bij een verzameld, Volume 2. Van Cleef, 1817. (exerpt)

[iv] Most of this paragraph is paraphrased from Verberg, Susan. The Rise and Fall of Gruit, 2018. As nearly all the citations are from foreign language sources, I chose to refer to the paper, not the individual sources.

[v] Of course, it’s a bit more nuanced than that, but not by much. In 1374 the grainbill of commercial hopped beer made in Hamburg was updated and part of the oats was exchanged with barley. This Hamburg beer became a very successful export product. Both German products were emulated by Dutch cities: rotbier under the name of hoppenbier and Hamburg beer under the name of koyt, making koyt the daughter of the beer that out-competed gruit ale. Private communication with Freek Ruis, 9/11/2018, thank you.

In the middle Ages you drank beer – if you could afford it.

Contrary to popular believe, it was not beer that was the most common drink of the middle ages: it was plain and simple water. Dependable sources of clean, fresh water – whether it be a running creek, a spring, or a well – would be incorporated into villages and towns as easy access to fresh water makes life better in so many ways. By the 13th century, as urbanization was invented and towns started to expand into cities, early industrialization did endanger the local fresh water supply. Medieval cities dealt with this in several ways: ordinances dictated where for instance tanners and dyers could operate, i.e. down stream, reserving the fresh upstream water for the city’s domestic use. And fines would be issued for contaminating water meant for household, and brewing, consumption.


Een Brouwers Water-Schuÿt (A brewers water-barge) by Reinier Nooms, 1652-54.

Water for brewing would be gathered from surface water like spring or creek water, rainwater, well water and by the Renaissance even from conduit water, as mentioned in A Profitable Instruction (1579): “wash [the honey comb] diligently with Conduit or fair Spring water, that you may so have the Mulse or hony water.” Monasteries and towns often had their own well water, and sometimes city neighbors chipped in to finance a private well in their district. Of course, such a well would be forbidden for use by outsiders upon penalty of a fine. Larger cities would build water-supply infrastructure to ensure the populace access to clean water. For instance, the city council of London began construction on the ‘Great Conduit’ in 1236 which brought water from a large fresh spring at Tyburn to the cisterns in Cheapside, and from there fed local cisterns all over London. Small barrels of water would be offered for sale, and while the medieval populace was aware that boiling water before use was a good idea – food poisoning has a quick learning curve – they were less aware of the connection between spoiled water and waterborne diseases.


Brouwerij De Drie Klaveren in Spaarne, Haarlem by Anthonie Beerstraten, 1660.

In 15th century the Netherlands many brewing procedures were also subjected to ordinances, including the ingredients used for brewing beer, the proportions of said ingredients, transport within and without the city, payments of taxation – and keeping the water in the city canals clean. A brewers’ ordinance from 1407, for instance, contains a warning for Zeeland skippers not to dump salt water (either from leakage, or used as ballast) in the canals within city limits. Dutch city brewers often found surface water not suitable for brewing, either from pollution from surrounding craftsmen, especially the textile industry – and from the creeping in of salt from North Sea ocean water into the fresh ground-water supply. Brewers would use water barges to gather clean fresh water, either from local lakes or from the coastal dunes (the sand acts as a filter). The water barges (image) would deliver straight to the brewery via the city canals, and the clean fresh water would be scooped out of the hold onto a wood gutter (image brewery) designed to transport the water from the quay straight into the brewery building.

An interesting story, uncovered in the city archives of Dordrecht, the Netherlands, follows an allegation of selling undrinkable beer by Brewery De Sleutel (The Key) – a medieval brewery which actively produced beer up until the corporation Heineken bought it out and stopped production in 1968.

On August 14th 1577, the head brewer Baernt Lambertsz. and his apprentice Aernt Aerntsz. were called up to the Dordrecht city court to make a statement under oath they used the grain, hops, and malt for the brew of August 1st from the same storage successful brews had been made before. Another apprentice Jan Adriaensz. van der Dussen witnessed that he gathered all the water for the brew from the well himself, as was his custom. The brewers did note that the brew on the coolships had a peculiar scent that they had never smelled before either in the brewery or anywhere they had brewed before. The city officials took the case serious and four days later, on August 18th, other witnesses were heard. The tapper Jan Jansz. remembered his conversation with carpenter Adriaen Lauwen about the quality of the surface water in the Nieuwe Haven, for which Lauwen blamed the dyer. Four beer carriers (beer transport has its own guild) witnessed they had had to return Sleutel beer from several taverns due to being undrinkable. At the request of the innkeeper they tasted the beer and remarked they’d never tasted something so peculiar. Then other beer carriers also tasted the peculiar beer and agreed that they understood why the tappers of the taverns had returned the beer, as no customer would drink of it. Unfortunately no more information exists on this case; no witness accounts of the accused dyer nor of penalties. Doubly unfortunate, the account illustrates industrial pollution is nothing new either.

In the middle Ages, alcoholic drinks were not consumed because water was thought to be unsafe, as is often thought; beer was consumed because it was seen as more nutritious. Not only were the brews often much weaker than their modern equivalents, but they also provided much needed calories to manual laborers, as well as being thirst-quenching and rehydrating in hot and sweaty weather. Ale and beer were a major part in keeping the laborers going, much like our modern Gatorade! Drinking water was seen as part of the four humors, blood, yellow bile, black bile and phlegm, and keeping those in balance achieved good health. (image four humors) Drinking too much water was seen as just as unhealthy as drinking to much of its counter part, a brewed beverage, and a brew often was diluted with water to keep the humors in balance, and to avoid unseemly intoxication. As beer and wine was more expensive, its consumption therefore gave status. If you could afford it, you drank beer.