Description
Kvass is a low‑alcohol fermented beverage made from rye or barley bread, where starches are converted to sugars and then fermented by yeast and lactic acid bacteria.
Technical
During fermentation, endogenous amylases in the bread hydrolyze starches into glucose, which is then metabolized by Saccharomyces cerevisiae to produce ethanol and CO₂. Lactic acid bacteria such as Lactobacillus spp. convert residual sugars into lactic acid, lowering the pH to 3.5–4.5 and imparting a characteristic sourness. The combined activity yields 0.5–2 % ABV and a mildly acidic, yeasty flavor profile.
Science
Primary Reaction
Starch → glucose → ethanol + lactic acid
Sensory Profile
Aroma ()
earthyyeastymaltysourbreadyfermented grainsubtle fruitinesshoney-likecaramelized bread crustherbal undertones