Kvass has been a common drink in Eastern Europe since ancient times, comparable with other ancient fermented grain beverages including beer brewed from barley by the ancient Egyptians, the millet beer of Africa, the so-called rice wines of Asia, the chicha made with corn or cassava by the native Americans.
There are a lot of ways to make Kvass. The simplest involves stuffing old stale bread to half fill an old bottle, filled up with water and a few raisins and left for a few days. The creamy bubbly white drink is full of lactobacillus, a tonic for for intestines. Most recipes call for more elaborate processes, toasting old (traditionally dark rye) breads and pouring on boiling water and leaving for some hours before filtering and adding yeast culture and flavoring such as mint, honey, cinnamon or fruit juices.
If you have a look online you can find all kinds of recipes and methodologies for making Kvass, including an apparent trend of making salted beetroot Kvass. House Kvass is typically made with black or rye bread baked into sukhari (croutons), yeast and zakvaska (kvass fermentation starter). The taste depends on the proportions of these essential ingredients. There are numerous variations of the following basic recipe;
Ingredients: rye bread, sugar, active dry yeast, water, raisins.
- Slice rye bread (250g) and bake in a pre-heated oven (150°C) for about 20 minutes until crispy.
- After that put the bread in a bowl, cover with boiling water and set aside in a warm spot for about four hours.
- Dissolve yeast in about 200ml of lukewarm water and add sugar. When the four hours are up strain the bread mixture through a colander lined with muslin or cheesecloth, keep the liquid.
- Stirr in the yeast mixture into this liquid, cover the bowl and set aside in a warm place for about ten hours.
- Strain the liquid once more through cheesecloth before and than pour it into clean bottles. Add two raisins into each bottle, then cork them and set aside in a cool place for three days to mature.
There is a famous saying "Bad kvas is better than good water." In Russia Kvass is used in some cold soup recipes such as okroshka, an ancient Russian dish made with vegetables and cold boiled meat and/or fish (in proportions one to one). Interestingly in 1913 Russian bacteriologists proved that Kvass is a germicide by showing that typhus bacteria die in the drink. Cheers, I'll drink to reestablishing our relationship to microbiology!