What You Need to Know
During fermentation, lactic acid bacteria metabolize residual sugars in the chickpea‑rice mixture, generating lactic acid and CO₂. The acid lowers pH, activating baking soda to release additional CO₂, which creates a porous matrix. Upon steaming at ~100 °C, starches gelatinize and proteins set, trapping the gas and giving the batter its characteristic spongy texture.
The Science
Primary Reaction
Lactic acid bacteria fermentation of sugars → lactic acid + CO₂; baking soda + acid → CO₂ + Na⁺ + H₂O