Cervoise (Barley Beer) – an Experimental Drink

at Malagne, Archéoparc de Rochefort (Rochefort ArcheoPark), Belgium.

By Florence Garit, Scientific Collaborator, Malagne.

The first-century CE Gallo-Roman villa located in Belgium on the site of Malagne, the Rochefort ArcheoPark, takes its visitors on a journey back in time (1). In addition to the visible remnants of two residential buildings, the domain also has reconstituted structures, as well as gardens designed to reflect the period. As well as this verdant setting, a stroll around takes you to see horses, sheep, a donkey, chickens, ducks, all of which illustrate domestic life on a Gallo-Roman farm.

The Malagne site is highly active in experimental archaeology and has recently built a brewery to show the public the scientific experiments that have been taking place over some twenty years. In this new space, visitors discover the raw materials needed to brew beer, the material produced, and the steps involved in producing this drink which has existed for millennia.

Reconstitution of a Gallo-Roman brewery © Malagne, Archéoparc de Rochefort

The earliest ‘beer’ brewing goes back very far, well before the Celts make the drink popular. Already made in the Neolithic, beer is a fermented drink produced with an apparently simple principle: hot water in which a richly starchy plant is steeped, which varies from place to place in the world. People have been making this drink for over 10,000 years with infinite varieties and the advantage that it often purifies unhealthy water.

Getting to know beer from Gallo-Roman times and attempting to rediscover its savours was a genuine challenge for the Malagne team. Although we know beer was drunk in this period, very little information is to be had about how it was made, the ingredients and utensils involved, not to mention the recipes of the time that were jealously kept by brewers and eventually lost. Archaeological research at times provides us with some clues, but structures discovered in digs are often hard to interpret, since they may have been used for other activities and do not always guarantee us they were brewing sites. Experimentation can thus be of undeniable value in rediscovering the secrets of this drink that is so emblematic of the whole region.

Research into the beers of Gallo-Roman times – one of which was called cervoise (barley-beer) in homage to Ceres, the goddess of harvest – began at Malagne in the early 2000s, when studying beer from a historical perspective was not yet the fashion in the world of scientific inquiry. In order to find a recipe and a brewing process, we turned to Philippe Voluer, beer historian and founder of the Stenay Beer Museum in France. Thanks to his work, we were able to start small-scale experimental production (3).

Before brewing, cereal grains must be soaked in water, then spread out in a cellar. After several days, they begin to sprout. Germination is fundamental to effectively release the sugars that will then be transformed into alcohol during fermentation. The touraillage (2) or malting interrupts this process and also produces, depending on the degree of roasting, both colour and taste of the future beer. Malt can be kept for several months, which distinguishes this step from making the beer itself.

Filtration © Malagne, Archéoparc de Rochefort

To condition it, we must first crush the malt, which makes absorbing the water easier. During the malaxing process, the hot water and malt are mixed. Then comes the brewing, when the temperature is gradually raised, releasing the various sugars from the grain into the water. Once this operation is carried out, we have the must, a sweet liquid that does not yet contain alcohol. Filtration eliminates the solid components called draff (or spent grains) and then the must is heated to boiling and flavourings are added. In Malagne, we have brewing plants from our reconstituted garden. After a second filtration step, the must is put into vats and the yeast is added. Now, the magic of fermentation can begin.

Although our first trials were rather laborious and had to be adjusted, today, amateurs like the beer we make, even though it is a bit far from modern versions. The experimental beer is more or less flat, often slightly acidic, and has an average alcohol content of 4.6° and 5.2°.

First trial at malting © Malagne, Archéoparc de Rochefort

After years of practice, our research moved in various directions. A new process was developed in 2019, thanks to knowledge supplied from contemporary brewers. So, instead of raising the temperature from one level to another stepwise with resting time in between, we now use a “direct heating” method. The mash is put on the hearth, and heated gradually up to 78°C. This is more rapid, more intuitive, and limits the risk of bacterial contamination.

Another line of research connected with beer brewing was begun recently: making the malt. Up to this time, experimentation focused on brewing and fermentation. Then we extended our research practices to all the steps necessary in beer-making, from the grains of barley to beer tasting sessions.

Volume N°5 in the collection Vi@Malagne

The cereals were germinated in a cellar, while the malting was carried out in the reconstituted brewery. This step was made on a small stove (called a touraille) built on the principle of a grain-drying kiln found during a dig and used to show the malting process to visitors. This structure is built with three limestone walls that hold up a schist flooring and daub bricks. We experimented drying the sprouted barley grains, the step before brewing, for the first time in November 2021. For over ten hours, two technicians kept a wood fire burning in front of the stove and mixed the barley grains we had let sprout before the experiment. This first trial proved to be conclusive and more experiments were to follow.

All our work on brewing beer of Gallo-Roman times is presented in Brochure N°5 in our Vi@Malagne collection, which came out in September of 2022 (3).

Author: Florence GARIT, Scientific Collaborator / Malagne, Archéoparc de Rochefort (archeologie@malagne.be)


1) Malagne, Rochefort ArcheoPark https://www.malagne.be/en/

2) This touraillage (drying process) is carried out by spreading the green malt on perforated metallic trays and drawing through this layer a draft of air or warm gas. While maintaining a fixed temperature in the malt, the evaporation is set in motion, hence the drying, by adjusting the draft or through a variable ventilation.

3) Musée de la Bière, Stenay, brought together researchers, volunteers, local politicians, and brewing experts to work on setting up the museum and its collections.