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


Yeast ring magic!

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As part of our Iron Age brewing experiment I had prepared a yeast ring in advance. Guided by historic instructions which mention a few hours would be needed to rejuvinate, early in the afternoon I added some of the first wort with the ring in a stainless steel starter bucket. For the next couple of hours I kept a clean kitchen towel over the bucket, but found nothing happening… and by the time we should have inoculated the wort, the yeast ring-wort was quiet as the grave.


Sir Arthur Mitchell toured some of the western islands of Scotland in 1768 and recounts how the natives of the Isle of Skye revived the yeast preserved on their wreath:

“The natives preserve their yeast in the following manner: They cut a rod of oak four or five inches in circumference, twist it round like a w[r]ythe, and steep it in fresh yeast for some hours, then hang it up and dry it. And whenever they need yeast they take down the twisted rod, and put it into a covered vessel amongst two or three pints of luke-warm wort, so in two hours thereafter they have fresh barm fit for immediate use.”

The next day, during clean up, I decanted the ring with the still-inactive wort into a brand-new gallon ziploc bag, zipped it, and brought it home to deal with later. To my surprise, guess what I found when the truck was unpacked? One ziploc balloon, with lots of foamy, bubbly activity!


Instead of taking a coupe hours, it took a couple days, but it work, and quite well too. After another day or two of vigorous fermentation the yeast was slowing down and I carefully removed the ring by its cord. I dried it outdoors, on a breezy and sunny day. It was visually dry within a few hours, which was quicker than I had expected. I gave it some more, as the weather was nice, and then stored it in another Ziploc bag in the fridge. In another month, I’ll revive it again, and see if we can get a quicker start. And if not, I’ll just start my ring the day before a traditional brew day, that’s OK too.


This yeast ring is made for me by Robert Hedstrom, from paint stirring sticks (likely pine) and is about six inches in diameter. I like the smaller size as it is easy to store and fits in my smallish stainless steel milking buckets. The yeast ring is inoculated with the standard Safale WB06 dry ale yeast, and is therefore now dedicated to this strain. This ring is a trial to test technique for using the more finicky kveik yeasts, the traditional Norwegian homegrown yeasts, and until then it will serve us well during traditional brewing demonstrations.



  • Mitchell, Arthur. James Robertson’s tour through some of the western islands, etc., of Scotland in 1768. Proceedings of the Society of Antiquaries of Scotland, Volume 32. Society of Antiquaries of Scotland, 1898.

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 some 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.

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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 start pulling stones, and added them to mash (the soaked grains) 3 or 4 at a time. Ulf really enjoyed this bit, as did my kid 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!



Last Call! Ale & Mead Tasting at the 54th International Medieval Congress

Sponsored by the Medieval Brewers Guild and AVISTA: The Association Villard de Honnecourt for the Interdisciplinary Study of Medieval Technology, Science, and Art; hosted by the Medieval Institute at Western Michigan University, Kalamazoo, MI.

All good things come to an end! At the final tasting at the Medieval Congress, soon-to-be-retired coordinator Stephen Law bid adieu and farewell to the brewers and tasters after organizing, and brewing, for 13 tastings over the past 20-odd years.


Organizer Stephen Law addressing the crowd of eager tasters.

In the words of Stephen Law:

“A variety of medieval-style meads and ales are presented today, including the return of some novel brewing experiments that we have done in the past. The term ‘metheglin’ is used to designate meads that have been flavored with herbs or spices; we have several on the tables today. Traditional meads are the purest form of meads, with nothing used to modify the flavor of the natural honey itself. Pyment is a blend of mead and wine; both a white and a red are again offered this year. Melomels have always been popular (especially here at Kalamazoo); our fruity blends are delightfully refreshing. ‘Sack’ – in current terminology – means strong or very strong mead. Be careful with the sacks, as they sneak up on you. Particularly welcome is a ‘washed comb mead’ made in the traditional manner that bypasses all filtration whatsoever.

Some of the ales in this year’s tasting are ‘vintage ales.’ Notably, the Once-Brewed and the Twice-Brewed ales, have returned for the ‘last call’ (they were made with the hypothetical Saxon method of brewing a super-strong ales). The three unique ‘Hildegard Ales’ were made for this year’s academic presentation (session 101) on Gruit Ales vs Hopped Ales; they are a derivative of her information in the Physica. We also have several experimental ales with mixtures of gruits.

Wacht heil! Drinc heil!


Patiently waiting for the clock to strike 5PM!

While Stephen Law provided the bulk of the beverages, several other brewers contributed as well, including husband and wife team Benjamin and Mary Sullivan (session 101 – Microbial Susceptibility of Hopped and non-Hopped Ales) and I (also in session 101 – Medieval Gruit Ales Revisited).


Mary Sullivan ready to share samples of the fruits of her brewing experiments.

About a dozen members of the Medieval Brewers Guild helped behind the tables, keeping all the pitchers filled, ready for pouring. The Medieval Institute provided the servers, who poured and thus took full legal responsibility. Between all of us, we still had trouble keeping up for a bit! We had an estimated 500 people partake in sampling our medieval offerings.


Medieval Style Ales (a short run-down):

Hildegard’s Mirtelbaum Ale (barley ale with organic myrtle leaves and berries); Hildegard’s Costmary and Fennel Ale (barley ale with costmary & fennel); Hildegard’s Aesh and Oat Ale (60% oats and 40% barley with EU ash tree leaves); Low Country Gruit Ale (oat/wheat/barley ale with bog myrtle, laurel berries, laserwort seeds and resin); Vintage Once-Brewed Saxon (single infusion mash, 11% ABV); Vintage Twice-Brewed Saxon (sparged with wort, 15% ABV); Viking Farmhouse Ale (barley, with yarrow, birch leaves, bilberry & angelica); Dry-hopped Wheat Wine (min. 50% malted wheat, dry hopped for 2 years, 14% ABV) Wormwood and Orange Peel Strong Ale (barley, wormwood, orange blossom sack, and curacao peel – not for pregnant women); Spiced Welsh Braggot (a blend of mead and ale, with galangal, ginger, cloves, pepper and cinnamon, 11% ABV); Hopped vs non-Hopped Experiment (a split batch barley & rye ale; one batch Northern Brewer Hops, other batch bog myrtle, mugwort, elder flower, juniper berries and licorice root).


The stash of mead, ready to be poured.

Meads and Cider:

Traditional Wildflower Sack Mead (24 lbs of honey, 15% ABV); Honey Comb Mead (honey straight from comb, including wax, propolus, pollen and all!); Rose Hips and Heather Metheglyn (24 lbs of honey, 15% ABV); Raspberry Melomel (13% ABV); Mixed Berry Melomel (organic raspberries, blackberries and blueberries; 13% ABV); White Pyment (wildflower sack mead blended 50/50 with Pinot Grigio); Red Pyment (wildflower sack mead blended 50/50 with Merlot); Lime and Ginger Mead (24 lbs of honey, 15% ABV); Hopped Metheglin Sack Mead (hops were used for both ales and meads in the late middle ages, 15% ABV); Spiced Sack Metheglin (Curacao orange peel, ginger); Strong Cyser (50/50 blend of mead and organic apple cider, 12% ABV); Cider / Perry Blend (heritage apple cier 2016, blended with pear concentrate, ca. 6.8% ABV).


Many happy conference attendees, trying one, or two, or several!

How to make a yeast ring

The Scandinavian Saga’s show the Vikings understood how to work with yeast to brew beer long before the first published Nordic books on brewing. Halv’s saga speaks explicitly of yeast, called dregg. Other words found in sagas are jǫstr, related to the Swedish ‘jäst’ and gerð, related to the the Danish-Norwegian ‘gær.’ As well as kvikur or kveykur, both linked to the adjective ‘kvick’ and meaning that which sets something in motion, related to the Norwegian ‘kveik.’

Many different methods of preserving yeast have been used over time, including the baking of yeast cakes with the addition of flour and the drying of yeast sludge on rough wood logs, straw wreaths of whittled yeast rings. For more on the history of Scandinavian yeast devices, check out my previous post at:

The most curious piece of brewing equipment, the yeast ring is mostly found in traditional Scandinavian farmhouse brewing. It would be used by drying yeast sludge on wreaths of straw or braided bark, as well as rings of small pieces of whittled wood. For this type of storage, the sludge could be dried quickly with the help of sterile hot ashes which would absorb excess water, the heat would help expedite drying, and the alkaline environment it creates would be antimicrobial. When Sir Arthur Mitchell toured some of the western islands of Scotland in 1768 he took note of how the natives of the Isle of Skye revived their yeast preserved on a wreath:

“The natives preserve their yeast in the following manner: They cut a rod of oak four or five inches in circumference, twist it round like a w[r]ythe, and steep it in fresh yeast for some hours, then hang it up and dry it. And whenever they need yeast they take down the twisted rod, and put it into a covered vessel amongst two or three pints of luke-warm wort, so in two hours thereafter they have fresh barm fit for immediate use.”

Practical instructions


Design of a Danish yeast ring, from the book Landbokvinden (Back to the land, 1964).

There are many different ways to make a yeast ring. Some are made simply from tightly twisted straw, others from strips of bark expertly braided together. Most are made from wood, often birch or beech, and most are made from narrow mortise & tenon pieces which are interlinked together. Some have a raised wedge head which keeps the pieces locked in, others have an indentation to the side. Some are square edged, some have rounded edges, and some have a decorative serration at the top, sometimes even at the bottom. Most have a square wedge head when seen from the top, and the measurements are often 2 wedge lengths makes up one body length (ratio 2:1), but sometimes shorter, at one and a half to 1, and sometimes much longer. On average, a good ball-park design to match many of the extant artifacts is about 75 pieces, or 25 sets of 3.

A modern reconstruction (left) made out of plastic with a 3D printer by George Hart (

Remekel a Bicska OCR-26-3b    Remekel a Bicska OCR-26-2b

A traditional reconstruction from the Hungarian book on whittling called Remeckel a bicksa (The knife is great, 1958).

This version seems to be the most common design and is probably indicative of the process: the many, many pieces would be carved or whittled by hand, with a knife, and the wedged end and slot (mortise) would not be problematic to create. This technique might also explain why it perhaps originated in Scandinavia – an area with a strong whittling tradition and long, long dark and boring winters.

The key to the puzzle

There are several options for the key piece which closes the loop, and could theoretically open it again. It is not quite clear what the benefit of taking it apart would be, except perhaps for a deep clean before it goes into storage (or to the museum). There are several museum artifacts which are disconnected (often also incomplete); the majority of the artifacts are connected and in one piece. None of the four key versions mentioned below are easy to re-open, and are all prone to damage when done so repetitively.

key pieces - composite

  • Key 1 (left): a piece with a minimally raised wedge, low enough so it can be pushed through the mortise. Optional: widen receiving mortise slightly as well. For cheaters: chisel the wedge off completely, insert piece, and glue back on. This key piece has to be the very first of the chain.
  • Key 2 (mid.): the tenon is split lengthwise from the middle of the back to the mortise. Then the two arms are sprung open and pushed over the body of the connecting link, similar to an old-fashioned clothes pin.
  • Key 3 (right): If the mortise is cut a bit wider than the link width, then it could be possible to remove just enough of the side wall to push through the other link. The part removed could be carefully glued back to remove all traces of construction.
  • Key 4: steam or boil the key piece ten to twenty minutes to soften the wood. Compress the wedge in a vice to flatten the wedge and insert through slot. As it cools and dries, it will re-expand somewhat and steaming can be used to expand it further. This is a known technique for making improbable wooden objects.


  • Loránt, Ferkai. Remekel a bicska, 1958.
  • Ole Højrup. Landbokvinden. Denmark, 1964.
  • Mitchell, Arthur. James Robertson’s tour through some of the western islands, etc., of Scotland in 1768. Proceedings of the Society of Antiquaries of Scotland, Volume 32. Society of Antiquaries of Scotland, 1898.
  • Thunæus, Harald. Ölets historia i Sverige I Från äldsta tidre till 1600-talets slut, 1968.



Scandinavian ‘magic sticks’ – yeast logs & yeast rings

Likely one of the first organisms domesticated by man, yeast was kept at the ready using many different storage techniques throughout history. One of the oldest such known practices are the Ancient Egyptian yeast breads: delicately baked little loaves of yeasty goodness which, when crumbled into sweet liquid, would create a new yeast starter – for beer, or to leaven bread. For most of man & yeast’s history, bread yeast and beer yeast were the same. The user often had a clear preference, either for keeping the top yeast (barm) or the bottom yeast (lees). But this preference seems more random than geographic, as one farmer would prefer the top, his neighbor the bottom and some would save both – and the yeast would be used for anything that needed fermentation.

two unusual yeast wreaths

A yeast ring made out of sheep vertebrae, Gjærkrans HF-00244 (left photo: Hadeland Folkemuseum) and a teethy straw yeast wreath, Jästkrans UM28850 (right photo: Uplandsmuseet).

There are many different, and some quite unusual, methods for keeping yeast found in Scandinavian context. Like the Ancient Egyptians, one method mixed yeast with flour and would knead it into a flat cracker, with or without a ‘donut’ hole. The crackers would be dried, and could be stored, nice and dry and out of the way, strung along the length of a hanging stick. In our more recent past, liquid yeast could be stored in bottles; often submerged in cold water such as in a well, which would act like a natural refrigerator.

Lars Garshol (2013): “Brewers usually preferred their yeast fresh, and if they didn’t have any, would borrow from their neighbours. This was common, and taking payment for yeast was unheard of. Some say well dried yeast could last for more than a year, and, if necessary, it could be revived with sugar and water, then dried again. Given how hard it is to keep yeast alive and working well, and how it seems to depend on a community of neighbours all helping one another it’s not very surprising that kveik has disappeared in most places.”

yeast logs

Yeast logs come in all different shapes and sizes: a jästkubb NM.0041501 (photo: Nordiska Museet), a gjærstokk from 1704, a gjærstokk NF.2016-0174 (photo: Norsk Folkemuseum), and a kveikal from 1621, NF.1928-0442 (photo: Norsk Folkemuseum).

Scandinavian Yeast Logs and Yeast Rings

An intriguing piece of Norse brewing equipment, and unique to Scandinavia, is the yeast log. From a simple piece of rough-barked birch log with a hole at the top to attach a rope, to elaborately drilled and carved sculptural Odes to yeast, the yeast log captures our imagination. When brewing guru Michael Jackson visited Norway he was mesmerized by the “magic sticks” he encountered there, functional yeast logs kept as family heirlooms long after commercial yeast became available. The log would be used by lowering it into the fermentation vat to catch the yeast that would form a foam on top. Then it would be pulled out, rolled in flour, dried for a few minutes, dipped again and this process repeated a few times. When properly covered in yeasty paste, it would be hung to dry.

Nordland-1969-Brewing and Beer Traditions in Norway-133-2

A yeast log carved at the bottom with the date 1621 from Telemark, Norway NF.1928-0442 Photo: Norsk Folkemuseum,

Another traditional piece of brewing equipment, most often found in Sweden and Denmark, is the yeast ring. Yeast sludge would be dried on wreaths of straw or braided bark, as well as rings of small pieces of whittled wood. For this type of storage, the sludge could be dried quickly with the help of sterile hot ashes which would absorb excess water, the heat would help expedite drying, and the alkaline environment it creates would be antimicrobial. When Sir Arthur Mitchell toured some of the western islands of Scotland in 1768 he took note of how the natives of the Isle of Skye revived their yeast preserved on a wreath:

“The natives preserve their yeast in the following manner: They cut a rod of oak four or five inches in circumference, twist it round like a w[r]ythe, and steep it in fresh yeast for some hours, then hang it up and dry it. And whenever they need yeast they take down the twisted rod, and put it into a covered vessel amongst two or three pints of luke-warm wort, so in two hours thereafter they have fresh barm fit for immediate use.”

The secret identity of the Yeast Ring

When the Scandinavian museum records were checked for yeast rings, many examples can be found but also something else: Ulrika Torell curator of the Nordiska museet (Nordic Museum) explained the “pannring” as follows:

“A so-called yeast ring, or yeast wreath, originally used for brewing beer and malt drinks. The wreath is placed in the fermenter where yeast residues adhered and were allowed to dry into the hollows of the wreath. In this way, a good yeast was preserved for the next brewing. The wreaths were made of wooden sticks or straw. When the homestead brewing needs eventually declined [yeast could now be purchased, as well as beer] the wreaths instead began to be used as trivets for pots and pans and got a new name.”


Yeast ring made by the author from swamp birch (Betula allegheniensis).

From the 19th century onwards, it is fairly easy to find examples of wood wreath trivets both in Scandinavian, and in Hungarian, culture. The digital collections of the Swedish and Danish museums especially list dozens of “pannring” objects collected in the late 19th to the middle of the 20th century. The same is found for Hungarian wood wreath trivets, there called cauldron wreaths – the oldest object is dated to 1860. But did they not get used before then, or did they not get collected and catalogued? It looks like unfortunately it is the latter. The concept of ethnography, the systematic study of people and culture, had only recently developed. Universities and private collectors would collect data and objects, most often from strange and foreign lands and peoples. But not until the industrial revolution was it realized by governments and universities alike that rural life as had been known since living memory was quickly fading away, replaced by modern conveniences like refrigeration and dry-goods stores. Ethnographers were sent into the field in their own countries to preserve what was left, and this push for the past is still visible in the influx of collection acquisitions in the late nineteenth century.


The Hungarian Kutyagerinc – used to keep round-bottom cooking pots from tipping. Photo: Arcanum online.

Hungarian Trivets

A neat example of a wood wreath trivet is the Hungarian kutyagerinc, or dog’s spine, as seen on the table in the photograph of the shepherds’ couple dining. In the words of Barna Gábor in his book A pásztorok muvészete (The art of shepherds, 1989):

“Most shepherd’s apartments have chimneys, smoky kitchens and open stoves and multiple families cook on the stove. There is also a kitchen in the Keszthely Empire where six families cook on a stove. The footed cauldrons, pots and pans are designed for this, and the fire is gathered around it. It is natural that the feet and the pot are rusty, which is not a problem; the people consider, the goal with open fire is a more delicious meal and a crunchy roast.

If the soiled dish is put on the beautiful white tablecloth, it will make a mess. For this reason, the shepherd carries a tablecloth surface-saver, which is called a kutyagerinc (dog’s spine) because it really resembles the backbone of the dog, but is assembled as a wreath. The kutyagerinc consists of two or three hundred parts intersecting each other, held together by the parts, so that one part is tightly connected to the other.

The good kutyagerinc is that which is cramped as close as possible. You don’t need to use glue, an adhesive, for the kutyagerinc, because it holds itself together. If the assemblage of the kutyagerinc is connected with two opposing parts, it can be turned so that the heads of the parts stand in a different direction [it rotates] and the wreath has a different visual. The two ends of the wreath are so cleverly hooked up that the observer can’t figure out how the hundreds of pieces are put together so wonderfully! The shepherd does something for pleasure. There is no benefit, it’s just nice!”

The wreath as a yeast ring

Whenever the whittled wreaths are displayed in musea or on the internet, Scandinavian visitors would immediately identify it as a yeast ring. The yeast ring identity seems to be deeply ingrained within the Scandinavian mindset, bringing up the question of how old this custom could be. While there exists that Norwegian yeast log carved on the bottom with the date of 1621, there is no such luck with yeast rings. Same with Hungarian kutyagerinc, the museum objects in the Scandinavian collections are mostly dated and/or acquired at the end of the 19th century to the middle of the 20th century. A chance encounter while leafing through the 1555 multi-volume Historia de Gentibus Septentrionalibus (A History of the Northern Peoples) by Olaus Magnus provided an intriguing illustration.

KIC Document 0001

Yeast ring, hanging outside the brewery. Olaus Magnus’ Historia de Gentibus Septentrionalibus (1555, p.445) and appears here with permission of the Silver Special Collections Department of the Library of the University of Vermont.

 On display: one yeast ring, hanging of a pole outside a drinking establishment, to indicate the brew was successful and ready for consumption. Interestingly, it was apparently such a normal tool that the use of the ring is not mentioned in the body of the text of the book. The earliest practical descriptions of brewing beer are from the 16th and 17th century, but interestingly, quite often the literal use of yeast is omitted. The brewers had words for yeast and knew how to treat it – it was nothing surprising or new. For instance, the Danish cook book Koge Bog (1616) instructs “When you put the yeast in, then make careful certain that you don’t put it on too hot or too cold, but when it is slightly more than lukewarm.” While the German brewer Christoph Kobrer (1581) includes a detailed chapter on “keep[ing] the stuff for brewing” (about preserving and reviving yeast), Olaus Magnus (1555) only mentions to use “a small quantity of older beer.” Englishman Andrew Boorde (1542) instructs to use nothing but malt and water and to never add anything to beer, except “yest, barme, or godesgood,” three synonyms for yeast. And if one might find it strange to hang a yeast ring out in in the open, keep in mind brewers back then did not know yeast was a creature, only that the sun and an airy breeze would help dry out the sludge more quickly, and that that was good. On the other hand, the ring could also be just used and cleaned, hung out to dry and sterilize in the sun, as medieval dairies were known to do with their wood equipment. Putting out the yeasty tool to indicate a job well done is not something unusual; there is a long tradition in Europe of using yeast related utensils as pre-period inn signs, like besoms (twiggy sweeping brooms) and ale-poles (the medieval variant of mash paddles).

The Swedish article by Nils Nilsson called Jästkransen (Yeast wreaths) from 1981 is interesting in regards to the practical use of tori. While it is not as detailed as for instance Odd Nordland in his Brewing and beer traditions in Norway: the social anthropological background of the brewing industry (1969) or Gösta Berg in Jäststock och jästkrans (Yeast log and yeast wreath – 1949) what Is interesting are the two photographs included. One is of a confirmed pannring / trivet, while the other is of a confirmed yeast ring. And it is clearly visible: the yeast ring is slathered in dried yeast, and the trivet has scorched edges from where the hot pots touched the wood. Note that while yeast sludge can be soaked and rinsed away it is impossible to clean scorched wood. And most of the wreaths collected as trivets do not show any indication of heat scorching, which seems to undermine the assumption of them actively being used as trivets.


From Nilsson: (left) Jästkrans, one of a pair acquired from Harlösa in Skåne in 1945, information about the use is missing. The dried substance between the sticks contains, apart from various “debris” residues, starch and yeast fungi. Diameter 15 cm. KM 47,356:2. (right) Wreath braided with sticks, according to Kulturens folk art catalog 1932, a trivet from Skåne, that is to say, a stand for a frying pan. Diameter 23 cm. KM 35.767.

In the words of Nils Nilsson, in his 1981 Jästkransen:

“Another method was to allow the yeast to dry, which gave significantly increased durability. The yeast must then be collected in a suitable way. From ancient towns in central Sweden and Norway it is known that they used to lay down a so-called yeast log or yeast stick in the yeast vessel, a piece of log of rough bark with recessed depths where the yeast mass was gathered into. The stick was then hung to dry and the yeast in the holes could then be preserved for a long time.

The same method has been applied with wreaths, which were usually straw bundles, but which in southern Sweden and Denmark were often composed of small sticks stuck into each other, or yeast rings. The wreaths could either be placed in the vessel like the yeast stick, so that the yeast flowed into the cavities, or “filled” by pouring the yeast over them. Otherwise, the approach was the same.

Wreaths composed of small wooden sticks are quite common in our museum collections. Very few of these have a clear function as yeast rings. In general, they are found as a trivet for saucepans, pots and the like. In this capacity, they still exist, usually manufactured and marketed as home-made supplies. The question is then whether the use of wreaths as a pot holder was developed only after ceasing to store yeast dried in wreaths, in other words a kind of functional retreat as it is called in scientific language. More likely, they have been used for both these purposes and that the connection with the beer yeast was forgotten after the use of brewing beer at home had disappeared”.


All websites listed were accessible as of March 22, 2019.

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. Unfortunately, the account illustrates industrial pollution is nothing new!

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.