What You Need to Know
The beverage is produced by spontaneous fermentation of steamed rice, where endogenous amylases hydrolyze starch into fermentable sugars, which are then converted to ethanol and CO₂ by yeast such as Saccharomyces cerevisiae. Lactic acid bacteria lower the pH, contributing to the characteristic tartness, while volatile esters like ethyl acetate impart a fruity aroma.
The Science
Primary Reaction
Glucose → ethanol + CO₂ (by yeast)