Kvass is a fermented beverage commonly made from black or regular rye bread. The colour of the bread used contributes to the colour of the resulting drink. 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 flavoured 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. Kvass is also popular in Harbin and Xinjiang, China, where Russian culture is a strong influence.