Gruit ale; version 1

Gruit ale is an herbed beer of the medieval Low Countries. Back then, the word gruit seems to have had many meanings. Firstly the medieval beer itself, the ingredient necessary to make this beer; the monopoly to produce and sell this ingredient, and currently the modern herbal craft beer made without hops. Medieval gruit was brewed in the medieval Low Countries of Flanders, the Netherlands and western Germany between the 10th to the 15th century. With the import of the new hopped beer from northern Germany at the beginning of the 14th century, the Holland brewers rapidly changed over to brewing with hops as well; the southern Netherlands held on to the traditional way of brewing to a greater or lesser degree up until the end of the 15th century.

What was in gruit

At first gruit was a combination of a grain product and preserving herbs. In order to keep gruit ale longer it was brewed with a relative high level of alcohol, and the current theory is the wort was strengthened by adding a syrup-like grain extract. In addition to this grain product generally also a combination of herbs was used, plus refined resin which also has a preserving effect. The herbs most often mentioned were either bog myrtle (Myrica gale) or marsh rosemary (Ledum palustre), laserwort (Laserpitium siler) and laurel berries (Laurus nobilis). Possibly hops was also used, especially in the transitional period from gruit beer to hopped beer. Only the accounts of Cologne mentioned the use of anise (Pimpinella anisum), juniper (Juniperus communis) and caraway (Carvum carvi); possibly because of a problem in sourcing the standard ingredients. As far as the historic sources show other herbs such as sage (Salvia officinalis) and yarrow (Achillea millefolium) often associated with gruit ale are most likely based on speculations from outdated research.

The transition to hops made the grain aspect of gruit superfluous and this technique in connection with gruit disappeared from living memory. Gruit beer as a medicinal herbal ale was remembered for longer. Included in Eenen Nyeuwen Coock Boeck from 1511 as one of the many healthy recipes for “den wech der ghesondheyt” (the road to good health) is a recipe Om Gruyt, ende Gruytbier te maken, the only known recipe for gruit ale.

The difference with present-day gruit

Born from the necessity for a better quality beer, and the genesis of sales tax which made many organizations and families rich; after the introduction of hopped beer this previously ubiquitous medieval beer quickly disappeared from the table. Barely mentioned in the 16th century, by the 17th century the practical knowledge of gruit had disappeared. Renewed interest in patriotic history in the 19th and 20th century, including in gruit, resulted in many theories; the most wild being duckweed, for which brewers had to pay gruitgeld to have it and other pond scum removed from their brewing water!

Most attention is paid to making an herbal beer, with the idea of gruit / herb ale in contrast to our modern hopped beer. New research indicates gruit did not consist of herbs alone and likely had some sort of a grain component. As it is not clear what kind of grain component – a malt extract to strengthen the wort? grain hulls to introduce yeast? – and this is our first historic gruit trial, we decided to focus on the historically appropriate herbs.

The grain bill

Most of the research seems to indicate early ale brewed in the Low Countries consisted mostly of oats, with added wheat and no barley. The area is well suited to growing oats and often the more expensive grains would be reserved for baking bread. For instance the 1340 recipe from Delft (which had transitioned to hopped beer about a century earlier) used 72 eightparts oats to 24 eightparts wheat for a moderate strength hopped beer called peat beer. As this is our first foray into brewing early period beer, we opted for a compromise grain bill and chose to base our grain bill on grain bills similar to the 1407 Haarlem recipe below (likely meant to make hopped kuit beer). It is rare to find images of original grain bill accounts, most are hidden deep within non-digitalized city archives.

The original document listing the 1407 grain bill for kuit beer sold in Haarlem.

More on the herbal contents

The herbs most often mentioned in connection with gruit seem to have something in common: not only do they have bittering agents which makes them more or less reliably antiseptic, they also contain substances that are mildly narcotic, psychotropic, or inebriating; resulting in enhanced intoxication, and hangovers. It is conceivable that initially the herbs were specifically chosen for this reason, as part of religious ceremonies and important feasts.

See the table below which herbal compounds were found in which gruit cities:

Bog Marsh Laurel Laserpitium
City Dates Myrtle Rosemary Berries siler Resin Hops Anise Caraway Juniper
Deventer 1339-1348 X X X X X
Wesel 1342-1381 X X X X
Dortmund 1390-1399 X X X X
Cologne 1391-1393 X X (X) X X X X X
Zwolle 1398-1411 X X X X
Duisburg 1417 X X X
Munster 1481? X X X
Osnabruck ? X X X X
Tecklenburg 17th c X X X

By the time of the bookkeeping inventories the beer brewing trade was already transitioning towards hopped beer brewing and it is not clear if the hops purchased under the umbrella of gruit was used to brew gruit ale, or sold as part of gruit taxation. For the recreation of our gruit ale we decided not to add hops.

The main herbal ingredient of gruit was bog myrtle (Myrica gale). In those areas where bog myrtle did not grow, marsh rosemary (Ledum palustre) would be used instead. In Western Germany the name gagel had also been used for marsh rosemary, and in Germany and Scandinavia the name pors had been used for bog myrtle. This made identification rather confusing, until their habitats are checked: the two plants grow mutually exclusive, with marsh rosemary’s habitat being circumpolar. This meant that western Germany and the Netherlands would use bog myrtle in the gruit, and further northeast marsh rosemary would be used.

As we intend to brew gruit (the term used for gruit ale in the Dutch speaking Low Countries) as opposed to gruiszing (the term used in the German speaking Low Countries) – and we have access to wild-harvested bog myrtle – we decided not to use marsh rosemary in our recreation.

Sourcing the herbal ingredients

Bog Myrtle
Bog myrtle is bitter and astringent which presumably gave gruit ale a distinctive taste: sharp, potent, and slightly sweet. Bog myrtle and the beer brewed with it had a reputation for headaches though recent brewing experiments recounted no such effects. Dutch herbalist Dodonaeus (1644) explained this effect: “The fruit taken with some drink goes to the head, and hurts the brain. Therefore if it is cooked with beer or brewed with it (which happens in several places) then the beer damages the head, it makes the head hurt, and makes people quite easily drunk.

Laurel berries
The laurel is a small tree originating from the eastern Mediterranean, including Turkey, Georgia and Greece. In the Mediterranean it can reach as much as 60 feet (18 meters), but transplanted to colder climates does not grow over a height of about 25 feet (7,5 meters). It is grown as a container plant in colder climates, and unless a greenhouse is available, likely will not fruit. The shrub has been cultivated in England since the 16th century.

We sourced our laurel berries from Penn Herb Co. Ltd.
https://www.pennherb.com/bay-laurel-berries-whole-16-037W16

Laserwort seed
Laserwort (Laserpitium siler) is a perennial plant belonging to the family Apiacea. It can reach a height of about 12–39 inches (30–100 cm) and resemblances Queen Anne’s Lace (Daucus carota). Laserwort occurs in central and southern Europe and grows in gorges and rocky slopes at an elevation of 2,600–7,300 ft (800–2,250 m) above sea level. Its seeds are spicy though somewhat buggy smelling; it is at the same time a slightly spicy and bitter tasting fruit. Laserwort is of the same family as the spices caraway and cumin.

We sourced our laserwort seeds from http://www.alplains.com/Catalog7.html

Resin
The resin we used was also wild harvested from a pine in the backyard. It took quite some experimentation, and creative out-of-the-box thinking, to figure out a method to clarify the resin without either burning it, or getting headache inducing fumes into the house. I ended up using tin cans as a filter and capturing container, and the wood stove for radiant heat and as a ‘fume hood.’ Resin intended for brewing needs to be heated, or clarified, not only to remove organics like bark and dead insects, but also to remove headache inducing volatile turpentine.

Deciding the measurements of the herbal ingredients

Bog Myrtle: Bog myrtle is a fairly well known herbal beer ingredient. It therefore was not too difficult finding brewing specifications. From previous experiments Brewer One also had personal experience brewing with bog myrtle leaves.
According to the Dutch brewing website Brouw-bier.nl a good rule of thumb is about 0.04-0.14 oz (1-4 g.) per 2.64 gallons (10 l.), added about 5 minutes before the end of the boil. This is lower that the Facebook group The Gruit Guild brewing herbs chart. Their recommendation for bog myrtle is ca. 1/10 to 1/2 oz per gallon, later in the boil (2g/L at 20 minutes inhibited lactobacillus souring). We chose the middle road, and used 2 g per 1 gallon.

Laurel berries: Information on brewing with laurel berries is near impossible to find. We choose to follow the 16th century Gruyt recipe and added 1 laurel berry per half gallon of ale.

Laserwort: There is absolutely no modern information available on brewing with laserwort. As laserwort is not included in the 16th century Gruyt recipe it was no help there either. Information from the purchase inventories indicate a connection between laserwort and laurel berries. First collected under one term, duræ species (Latin) and zwaercruyt (Middle Dutch), in later accounts the term was separated into serpentijn and bakelaar. Serpentijn (laserwort) and bakelaar (laurel berries) were often sold in pairs. This could indicate the two were used in even proportions, and purchasing in pairs would result in an even amount in inventory. Therefore we chose to use the same amount of laserwort seeds as laurel berries, or 1 seed per half gallon.

Resin: Even though resin is mentioned in the 16th century Gruyt recipe, it is not listed with a measurement, merely mentioned as ‘also much resin.’ As resin can be overpowering, and is not part of our modern taste pallet, we chose to go light on the resin.

Brewing day

An online recipe creation tool to construct the grain bill was used for this experiment.

We chose rolled oats because they appear to be the most historical: it’s the entire grain of the oat, and flat, as opposed to steel-cut, which results in thicker chopped pieces that don’t seem to have the same characteristics.

For wheat we used an America white, because it was readily available at the local brewing supply store. We have not yet investigated how closely that particular choice may reflect historical varieties of wheat available to northwestern European brewers.

A German Pilsner barley was chosen as being the mostly appropriate variety currently accessible, but again, we have not yet investigated the history of barley varieties.

A Belgian yeast was selected, based on taste: earlier experiments of similar brews used that and an ale yeast, with Belgian yeast tasting better to us. Of course today’s modern highly refined and controlled yeast-producing and packaging techniques leave us with a very controlled aspect of our brew, which would simply not have been the case historically. While brewers may have had some control over their yeast, even without understanding its nature, it’s most likely that at least some wild yeast would have been involved in fermentation, given open-air vats and less sanitation capabilities. The variety of yeast used makes a significant difference in taste and possibly alcohol content; it will be interesting to try this recipe with a helping of Brettanomyces at some point as well.

The adjuncts (bog myrtle, laurel berries, laserwort seeds, and resin) were placed into a bit of cheesecloth tied with linen thread to make a sachet, which was placed into primary for the duration.

Brewing took place on March 22, 2018, with primary in two single-gallon carboys for 10 days. During the first couple of days, each gallon was swished around to help the adjunct’s sachet stay wet. Bottling occurred on April 1, with 1 tsp. white sugar added for conditioning, which we usually see drinkable after another 10 days.

We left our two experimental results – one with resin, and one without – unlabelled as a way for the judges to enjoy the result without knowing which is which. Contrary to expectations, we, the brewers & the judges, preferred the version with the resin!

 

Observations

– The differences in brewing between modern and historic grains would be quite interesting to know more about. Grain has be selectively bred for production since early man became a farmer and many historic grain species just do not exist anymore (they evolved).

– Both brewers like to continue their collaboration and keep experimenting with different ratios, ingredients, and so in order to explore early brewing in more depth and to greater extent.

– For now, we’re experimenting with the herbal aspects of gruit ale. When we know what works best in which configuration it is time to add the unknown grain additive to the mix. Does adding herbed malt extract indeed make for stronger, sweeter ale? Does adding chaff indeed introduce yeast? Intriguing questions, making for great new experiments…

 

Sources

For the research behind the ale you can read and download The Rise and Fall of Gruit at Academia.edu: https://www.academia.edu/35704222/The_Rise_and_Fall_of_Gruit

For the Gruit Ale: version 1 pdf (and its copious citations) written for the Arts & Sciences Brewing Competition, please check: https://www.academia.edu/36526760/Gruit_Ale_version_1