Kvass is a Russian beverage that, like most alcoholic drinks, is made from grains. However, the main ingredient is not raw grain but already baked, dried bread. In Russia, rye bread is usually used, though wheat and barley breads will work, too. Actually, people from Russia and Eastern Europe would argue that kvass is not an alcoholic beverage at all. The alcohol content is usually about 1 percent, and it is classified as a soft drink in the countries where people drink it. Kvass is sold on the street at open-air kiosks in many cities.
Kvass can be made at home. The process involves baking or frying the bread until it is dry and adding sugars, yeast and some sort of fermentation starter. The drink is often served unfiltered, which actually gives the drinker a high dose of B vitamins (from the yeast).