Fermenting Batters

Idli and dosa begin the night before: rice and urad dal soaked separately, ground (roughly for idli, fine for dosa), mixed with a little of the previous batter or left to their own wild yeasts, and kept warm overnight. By morning the batter has risen, soured faintly, and smells alive.

Salt goes in after the ferment, not before. Steam idli from the thick batter; thin the dosa batch with water and trust the pan’s patience. The sourness is not a flaw — it is the leavening, the flavour, and in the older kitchens, the point: fermentation was preservation and predigestion both.