Kvass is a fermented beverage made from black or regular rye bread. It is classified as a non-alcoholic drink by Russian and Ukrainian standards, as the alcohol content from fermentation is typically less than 1.2%. Generally, the alcohol content is low (0.05% – 1.0%).
It is often flavored with fruits such as strawberries and raisins, or with herbs such as mint. Kvass is also used for preparing a cold summertime soup called okroshka.
It is especially popular in Russia and Ukraine, but also well-known throughout Belarus, Estonia, Serbia, Poland, Latvia and Lithuania, as well as in other former Soviet states such as Georgia, Kazakhstan and Armenia where many kvass vendors sell the drink in the streets.