Kvass is known to Slavic tribes for over a thousand years. I t is known that eastern Slavic tribes had the recipe long before the formation of Kiev Russia. The first time it is mentioned in scriptures is dated in year 989: After baptizing grand duke Vladimir I Svyatoslavovich ordered to distribute among the people "food, honey and Kvass". The drink was known in neighboring Poland and Lithuania as well.
In Russia Kvass was widely spread as an everyday drink: it was made by peasants, and landlords as well as clergy and military. The presence of Kvass in the house was thought of as a necessary element of wellbeing. Russian peasants, going to the field or any other heavy kind of work, were sure to bring Kvass along, as they were belived that it was capable of reliving tiredness and restore strength. This effect is confirmed by modern day studies. In certain situations, Kvass was attributed healing powers. During the time of Lents, especially in the summer, the main ration of common people was Kvass with scallions and rye bread.
Kvass is a drink of a very long tradition. First prototypes of the drink, which were something of a cross between Kvass and beer, were known in ancient Egypt in 6th millennium B.C. Descriptions of very Kvass like drinks can be found in works by Herodotus, Hippocrates and Plinius Sr.. A fruit flavored Kvass variety was known in Babylon, although it did not spread throughout Mesopotamia.