What You Need to Know
During fermentation, lactic acid bacteria metabolize the carbohydrates in the rice and dal, producing lactic acid, acetic acid, ethanol and CO₂, which lower the pH to ~4.5–5.0 and create a protein–starch matrix that expands upon heating. The acidic environment also enhances flavor development and improves batter aeration, while the ethanol and CO₂ contribute to the characteristic lightness of the cooked dosa.
The Science
Primary Reaction
Lactic acid fermentation of carbohydrates by lactic acid bacteria