Kvass is a mildly alcoholic, lightly sour beer of Slavic origin, commonly made from rye bread or flour and flavored with mint or fruits. It is today available on street corners in Russia, Latvia, Uzbekistan, and many other countries of the former Eastern bloc, where it is often dispensed from mobile tanks, as well as in 2-l bottles, like soda (to which it relates as much as it does to beer). Its production origins are as temporally distant and as vague as many other house-brewed refreshments, but it is said to have been a staple beverage in these parts of the world for thousands of years. Kvass is mentioned in such works of classic Russian literature as Chekhov’s The Cherry Orchard, Dostoyevsky’s The Brothers Karamazov, and Tolstoy’s The Death of Ivan Ilyich.

Like the origins of brewing itself, early versions of kvass were no doubt the result of happy accident, with spontaneously fermented mixtures of water and either stale rye bread or flour yielding a beverage of slight sourness and mild alcoholic content. Commercial versions were more likely to be fermented with added brewing yeast, although home versions would use more commonly available baking yeast. Various fruits have been used to flavor kvass, including lemons, raisins, and strawberries, as well as to mitigate the sourness of the ferment. Today non-alcoholic versions are sold alongside soft drinks such as Coca-Cola. Aggressive efforts by large producers have sought to engender an indigenous pride in kvass, a traditional beverage of the region, against more globalized products.

See also russia.