Period: The Bronze Age (1700 - 500 BC)
Project titel: Gådefulde Kogegruber
Researcher: Ulla Odgaard, Archaeologist & Peter Steen Henriksen, Cand. Agro, The National Museum of Denmark, Copenhagen
E-mail: ulla.odgaard(at)natmus.dk
Year: 2008
Research Problem:
Approximately 6000 years ago farming came to Denmark. Gradually grain became part of the diet and people became more and more settled, in order to tend to fields and household animals.
All the same, analysis of skeletons form the Mesolithic period, show that the hunter/gatherers lived quite a good life. In fact, it was in many ways a less demanding life than the life of a farmer, where the harvest could fail and the work in the fields was hard. Therefore many scientists believe, there must have been a very special reason for this radical change in lifestyle, from hunter/gatherer to farmer. One of the reasons could well be, that grain does not only give us bread or porridge, but also a very special golden drink, which is still very popular all over the world today – Beer!
To make beer you need malt, which is sprouted and toasted grain, of for instance barley, which is one of the oldest cereals in the world. Some of the oldest finds of carbonized grain are from Denmark, is from the Bronze Age and consists of just such malted barley. Malted grain contains vitamins and other nutrients, which is otherwise not present in a grainbased diet. In this respect beer brewing can be quite a sensible way of exploiting the nutritional value of grain.
Also from the Bronze Age, a group of very characteristic pits are known. These stone lined holes in the ground are usually interpreted as “cooking-pits”, where red hot stones were used to cook food. The characteristic pits only some times contain bones and ceramics, indicating cooking activities, but strangely clean pits are also found, were only the heated stones and discarded grinding stones remain. This indicates heating and grinding of grain, which makes it feasible that these pits were used for brewing beer.
It is an archaeological fact that fermented drinks were produced as far back as the Bronze Age - and perhaps even in the later part of the Stone Age. The purpose of this experiment is to investigate, which traces experimental beer-brewing process creates, using the "cooking pits" technology. The experiment is to determine whether it is even possible to brew beer in ground pits.
Researcher's Conclusion:
Two experimental pits were dug out and lined with organically tanned cowhides and proved to function well as beer-brewing vessels. Water with added malt was heated to a temperature of 65-70 Degrees Celsius, using stones heated in an open fire to a temperature of 800 Degrees Celsius. Through the heating process the starch in the malted grain was transformed to sugar, making the water sweet and rich in sugar.
When the fluid was once again cool, wild cranberries were added to one of the pits, which started the fermentation, due to the wild yeasts on the surface of the berries. The fermentation in the other pit started spontaneously without any added yeast due to natural yeast in the air. After four days of fermentation the fluids in both pits had transformed to 120 litres of sweet and very tasty beer. Two days later, however, the beer had turned into vinegar, which leads to the conclusion that beer brewed in open pits should be drunk as soon as it is ready!
The experiment showed that pits of this kind are well suited for brewing beer, among other reasons because it is the easiest way to make a very large vessel. It took only 10 minutes to dig a pit with a volume of 100 litres.
Status:
After the brewing the pits will be filled in with the dug up earth and cooking stones, enabling us to dig out the pits in 2009, and compare them with the original prehistoric pits.
Reference number HAF 15/08