Dosa is a thin, crisp, slightly sour South Indian crepe made from a fermented batter of rice and urad dal (skinned black gram). It’s eaten with coconut chutney and sambar, or rolled around spiced potato for masala dosa. The batter is a close relative of idli batter, with more rice – often including some raw rice – and a little fenugreek, and it’s thinned so it spreads on a hot griddle (tawa).
Why the Batter Ferments on Its Own
Rice-and-urad batters need no added yeast. Studies of idli batter, which has the same ingredients, found that Leuconostoc mesenteroides both sours the batter and produces the gas that makes it rise, followed by Enterococcus and Pediococcus (Mukherjee et al., 1965), and that lactic acid bacteria – led by Weissella – make up the great majority of the microbes. They come in on the grains themselves: surface-sterilized grains didn’t ferment (Mandhania et al., 2019). Fermentation gives dosa its tang and helps it brown and crisp.
Batter Tips
- Ratio: about 4 parts rice to 1 part urad dal by volume for crisp dosas; more dal makes them softer.
- Fermenting: 8–12 hours at about 25–32°C; longer in a cool kitchen. It’s ready when risen, bubbly and pleasantly sour.
- Consistency: before cooking, thin it with water until it pours like thick cream.
- Too sour? It fermented too long or too warm – refrigerate it as soon as it’s ready next time.
- Sticking? The pan isn’t hot or seasoned enough: heat it well, wipe with a little oil (or a cut onion dipped in oil) and sprinkle water – it should sizzle away – before each dosa.
Is Dosa Healthy?
Dosa is a gluten-free, mostly rice-based flatbread; how healthy it is depends on the oil or ghee used and the fillings. Cooking kills the batter’s bacteria, so dosa isn’t a probiotic food. For a steamed, oil-free option from the same batter family, make idli. Other fermented batters around the world include Ethiopian injera and Sudanese kisra. The same dal makes sun-dried wadi, and a fermented flour batter becomes the syrup-soaked sweet jalebi.