Bread kvas is a traditional Russian fermented beverage made from stale bread. It has a tangy and slightly sweet flavor, similar to a light beer. The bread is soaked in water and mixed with sugar and yeast to start the fermentation process. After a few days, the liquid is strained and chilled. It is a refreshing and thirst-quenching drink, perfect for hot summer days. Bread kvas can be enjoyed on its own or used as a base for cocktails.