Kvass is a traditional fermented beverage popular in Eastern Europe, particularly in Russia and Ukraine. It is typically made from rye bread, which gives it a slightly sour taste and a dark color. The fermentation process involves adding water, sugar, and sometimes fruits or herbs, resulting in a low-alcohol drink, usually around 0.5% to 2% alcohol by volume. This refreshing drink is often enjoyed in summer and can be served chilled or at room temperature. Kvass is not only a popular thirst-quencher but also a staple in many households, often used in soups or as a base for other dishes.