Idli Dosa Batter Ratio: Urad, Rice and Winter Fermenting
For idli, use 3 parts idli rice to 1 part whole or split urad dal by volume; for dosa, 3 or 4 parts rice to 1 part urad. Winter is the real test: batter needs a spot around 25 to 30 degrees C to rise, and a cold North Indian or Pakistani kitchen rarely gives it.
The short version
- Idli: 3 cups idli rice (or parboiled rice) to 1 cup urad, a pinch of methi seeds optional.
- Crisp dosa: 4 cups rice to 1 cup urad, plus a small handful of poha.
- Soak: urad 4 to 6 hours, rice 5 to 6 hours, both in clean water.
- Ferment: 8 to 12 hours in summer, 14 to 24 hours in winter, in a warm spot.
- Keep: 3 to 4 days chilled, as a common kitchen habit; throw out pink, slimy or fuzzy batter.
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What is the right idli dosa batter ratio?
There is no single holy ratio. Households in the south run anywhere from 2:1 to 4:1 rice to urad, and each one swears by theirs. The ratios below are widely used starting points, measured by volume with the same cup for both grains.
| Use | Rice : urad | Result |
|---|---|---|
| Soft idli | 3 : 1 | Fluffy, holds shape |
| Extra soft idli | 2.5 : 1 | Very soft, can turn sticky |
| Crisp dosa | 4 : 1 | Thin, lacy, golden |
| Soft set dosa | 3 : 1 | Thicker, spongy |
More urad gives a softer, airier batter because the dal is what traps gas and swells. More rice gives crispness. If your idli come out hard, the first thing to change is the urad, not the steaming time.
How long do I soak and grind?
Soak urad and rice in separate bowls. Urad needs 4 to 6 hours; rice does fine with 5 to 6. Rinse each 3 or 4 times first. Drain, then grind the urad first with cold or lukewarm water added in small splashes until it is pale, airy and doubles in volume, which takes roughly 15 to 20 minutes in a wet grinder and a bit less in a strong mixer in short bursts.
Rice goes next, ground to a fine rava feel for idli (slightly gritty between your fingers) and smoother for dosa. Mix the two by hand for a full minute. The warmth and natural microbes on your hand are part of the old method, and it also folds more air in.
- Rinse and soak the urad and rice separately, as above.
- Grind the urad until fluffy and pale. Stop the mixer when the motor gets hot, so the batter does not cook.
- Grind the rice, then combine both in a large steel or glass container with room to double. Use a vessel at least twice the batter volume.
- Add salt now in warm weather. In cold weather some cooks add it after the batter has risen; both work, so follow whichever has served your kitchen.
- Cover loosely and leave in a warm spot.
Cook’s trick: a handful of poha
Soak a small handful of poha for 15 minutes with the rice and grind it in. Many cooks add it for softer idli and crisper dosa. Cooked rice, about two tablespoons, does the same job. It is a kitchen habit rather than a rule, so test it once on a small batch.
Why will my batter not rise in winter?
The microbes that make bubbles in batter slow down sharply when the room is cold. A kitchen at 15 degrees C can leave batter flat for a full day. Chilled water at grinding and a cold steel vessel make it worse.
Fixes that work in a North Indian or Pakistani winter:
- Oven with only the light on. The bulb gives gentle warmth. Place a thermometer inside if you can; around 25 to 30 degrees C is the goal. Stick a note on the oven door so nobody preheats it with the batter inside.
- Rice cooker on keep warm. Set the batter container on the lid or beside it, never inside a hot pot.
- Hotpot or insulated box. Fill the casserole with hot water, put the batter bowl in with the lid shut.
- Above the fridge, or next to a gas geyser. Surprisingly warm spots in many flats.
- Lukewarm water at grinding. Hand warm, not hot. Use water that has stood a while rather than freshly chlorinated tap water if your supply is heavily treated.
If it still sits flat after 24 hours, a spoon of sour, active batter from a previous batch (or one teaspoon of plain dahi) can help seed it. Do not hold out beyond a day and a half in a warm spot; it will turn sour long before it rises properly.
Winter batter used to be wrapped in a quilt or put near the chulha’s warm wall overnight. The principle is the same as your oven light: steady, gentle warmth, never direct heat.
How do I know the batter is ready, or gone wrong?
Ready batter has risen to roughly double, looks bubbly on top, and smells pleasantly sour, like mild dahi. Stir gently and it should fall back and feel airy.
Discard it when you see any of these:
- pink, orange or grey patches or streaks;
- fuzzy or dotted growth on top (mould roots go deeper than the visible spot, so do not scoop it off);
- a slimy, stringy texture;
- a sharp, rotten, or eggy smell instead of mild sourness.
A strong but clean sour smell usually means over-fermentation. That batter is still safe, but idli will be dense and a bit tangy. Add a spoon of fresh rice flour and cook it as dosa or uttapam. Our guide to fermentation in dahi, idli and kanji explains the chemistry.
How long does idli batter last in the fridge?
Most home cooks keep it 3 to 4 days chilled, which is a kitchen habit and not a scientific limit. Chilling slows everything but does not stop it, and the NHS lists food stored badly or left out too long as a main cause of food poisoning. So: refrigerate once the batter has risen, keep it covered, use a clean spoon each time, and stop using it when any warning sign above shows up.
Take out only what you need and let it come to room temperature for 30 minutes before steaming. Cold batter gives dense idli. See also how long cooked dal and batter keep in the fridge.
Why are my idli hard?
- Too little urad, or urad not ground long enough to turn fluffy.
- Batter did not ferment, or fermented so long it collapsed.
- Batter was stirred too hard after rising, pushing out the air.
- Steaming started with cold water in the pot, or the lid was lifted early. Steam 10 to 12 minutes on a good boil.
Hard water from the tap can also toughen pulses in the grinder stage; see why daal will not soften in hard water. And if you only use urad as a daal, the mash daal guide covers it.
Can I make idli batter without a wet grinder?
Yes. A strong mixer grinder works if you work in small batches, add cold water by the spoon, and give the motor rest breaks. Use soaked, drained dal and rice and grind each in two or three rounds. Without any grinder, ready-made idli rava (rice semolina) with soaked, mixer-ground urad gives a respectable idli.
Fermented batter is not a way to rescue food that has spoiled. If you are pregnant, elderly, or have a weak immune system, be stricter and throw out anything that looks or smells off. Stomach pain, repeated vomiting or diarrhoea after eating any leftover food needs a doctor, and a child with these signs should be seen the same day.
Questions people ask about idli and dosa batter
What is the best idli batter ratio?
Three parts idli rice to one part urad dal by volume is the most commonly used starting point. If your idli turn out dense, move toward 2.5 to 1, which means a little more urad.
What is the dosa batter ratio of urad dal to rice?
Four parts rice to one part urad gives crisp dosa, and 3 to 1 gives a softer, thicker one. A small handful of poha added during grinding helps with crispness.
Why is my idli batter not fermenting in winter?
The room is probably too cold. Move the batter to a warm place around 25 to 30 degrees C, such as an oven with the light on, and give it 14 to 24 hours instead of 8.
How long should idli batter ferment?
About 8 to 12 hours in warm weather and 14 to 24 hours in winter. Look for rise and bubbles rather than the clock.
Why does my idli batter smell too sour?
It has probably fermented too long or in too much heat. If there is no mould, pink colour or sliminess, it is usually safe, and best used for dosa or uttapam rather than idli.
How long does idli batter last in the fridge?
Many households use it within 3 to 4 days. Keep it covered, use a clean spoon, and discard it earlier if it changes colour, turns slimy or smells off.
How long should I soak urad dal for idli?
Four to six hours is enough. Longer soaking in warm weather can start souring the dal before you grind it.
Can I make idli batter without a grinder?
You can use a mixer grinder in small batches, or soaked urad with ready idli rava. The result is slightly less fluffy than a wet grinder batter but still very good.
Why are my idli hard?
Most often there is too little urad, the batter did not rise, or it was stirred hard after rising. Steam on a rolling boil for 10 to 12 minutes without opening the lid.
Should I add salt before or after fermenting?
Both ways work. Many cooks add salt before fermenting in warm weather and after in cold weather, but this is preference, not a fixed rule.
Sources
- NHS: Food poisoning (causes: food not stored correctly or left out too long)
- USDA FoodData Central (open data feed): rice, white, raw
More grain and pulse guides live in Grains, Daals & Pulses.