Kvass is Russian for “leaven” and is a 16th century beer-like beverage made with grains – wheat, rye, barley, etc – or dark rye bread, and often has additions of sugars, birch sap, berries, fruits; the process is akin to ancient beer brewing. It’s basically a fermentation of what’s around with a simple bakers yeast. It’s low in alcohol and often flavored with herbs or fruits to knock the bitter edge out.
A national drink for Russia, but also found throughout Eastern Europe.
Average alcohol by volume (abv) range: 0.5-2.5%