Introduction:Kvass is a traditional Eastern European fermented drink typically made with stale, toasted sourdough rye bread. While bread kvass is the most popular, other versions exist including those made with beets and fruit.Kvass is a fermented cereal-based low alcoholic beverage with a slightly cloudy appearance, light-brown colour and sweet-sour taste. It may be flavoured with berries, fruits, herbs or honey. Kvass (spelled also as kvas) is a traditional Russian beverage typically produced from rye or dried rye bread by natural fermentation. Kvass has been very popular in Russia and the former Soviet Union; consumption has increased due to massive advertising