What You Need to Know
During steeping and boiling, starch granules gelatinize and proteins denature, releasing maltose from starch breakdown. Lactic acid bacteria then ferment the maltose at 30–35 °C, producing lactic acid and lowering the pH to about 4.5 over 24–48 h. The process yields a mildly sour, nutrient‑rich drink with a characteristic grainy aroma.
The Science
Primary Reaction
Starch gelatinization and lactic acid fermentation