What are the two main ingredients in idli batter?

What are the two main ingredients in idli batter? Rice and urad dal are the answer.

Idli batter traditionally combines rice with hulled black gram, known in Hindi as urad dal. The rice provides structure, while the lentils contribute proteins and help create the soft, airy texture associated with steamed idlis.

The ingredients are usually soaked separately for several hours, ground, mixed, and left to ferment overnight. Naturally occurring microorganisms produce carbon dioxide and acidity during fermentation, which helps the batter rise and gives idlis their characteristic mild tang.

Idlis are steamed in perforated molds and commonly served with sambar, coconut chutney, or other accompaniments. The classic recipe should not be confused with rava idli, a Karnataka variation made with semolina. Historical references to idli-like foods date back to a 920 CE Kannada text, although early versions may not have used rice or modern fermentation methods.