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.