Kwas Chlebowy (Kvass) is a traditional non-alcoholic Slavic and Baltic fermented drink usually made from rye bread. It has a sweet-sour smell and a taste of freshly baked bread. As well as being drunk in Poland it is also popular in Russia, Latvia, Lithuania, Estonia, Belarus and Ukraine. Some claim that Kwas can improve digestion, as with other fermented foods such as yogurt and sauerkraut. And being derived from Rye is is a good source of vitamin B-1 and B-6, magnesium, phosphorus, and amino acids.