Fermentation questionsઆથાના સવાલ
Fermentation is the least predictable thing in a home kitchen — same measures, same flour, a different result every time. These answers explain what the batter, the atho, the steam and the Eno are actually doing, so the next round is judgement rather than guesswork.
How long does batter take to ferment in winter and summer, and where should I keep it?
In summer heat, when the kitchen is around 30 to 35 degrees, a besan or rice-dal batter is ready in six to eight hours. In winter at 15 to 20 degrees the same batter needs twelve to eighteen hours, and in a hard cold spell it can take a full day. Fermentation is bacteria and wild yeast eating the starch and giving off carbon dioxide; they work fast when warm and almost stop below 15 degrees. So in winter give the batter a warm pocket: the oven with only the bulb on, a closed casserole, a cupboard above the fridge, or wrapped in a thick blanket with a bottle of warm water beside it. Keep the vessel no more than two-thirds full, because a good atho lifts the batter. One mistake comes up again and again — setting the vessel on a warm tava or in direct sun. Above 45 degrees the culture dies and the batter just turns sour without rising.
How do I know the atho is done?
Look for three signs together, not one: the batter has risen by about half again, the surface is covered in small bubbles, and it smells pleasantly sour like curd rather than sharp or alcoholic. Stir once with a spoon and the inside should look airy and honeycombed, and the batter should feel lighter and looser than when you ground it. For idli batter there is an easy test — drop half a spoon into a bowl of water; a fermented batter floats, an unfermented one sinks. Of all the signs, the rise is the most reliable, so mark the level on the outside of the vessel with a rubber band or a marker before you leave it. The biggest mistake is deciding by the clock. Twelve hours in a cold kitchen can leave the batter untouched, while eight hours in May can take it past its peak, so look at the batter and not at the time.
What do Eno and baking soda actually do, and why do they go in at the last moment?
Both release carbon dioxide inside the batter, and those bubbles are what make khaman and dhokla light. Eno is a fruit salt: baking soda plus a dry acid, usually citric or tartaric. The moment it touches wet batter the acid and the soda react, so it needs no help from you and gives everything it has within a minute. Plain baking soda is soda on its own, so it needs acid in the batter — lemon juice, curd or citric acid — otherwise it only part-reacts and leaves a soapy taste. That is why both go in last: stir for four or five seconds, pour into a greased thali, and set it over boiling steam straight away. If the steamer is not ready, the gas escapes while you wait and the dhokla sinks. Per two cups of batter, use about one teaspoon of Eno, or three-quarters of a teaspoon of soda with a teaspoon of lemon juice.
Why does my dhokla come out dense or rubbery?
Almost always one of four things. First, the batter was stirred or the vessel carried about after the Eno went in — every stir beats the gas out and the piece sinks. Second, the steamer water was not boiling, so the gas was spent before the heat could set the batter. Third, the batter was too thick; it should be pourable but thick, roughly like idli batter, because a stiff batter cannot hold a bubble open. Fourth, the Eno or soda was old; both lose strength once the packet has been open for months. Rubbery rather than dense is a different fault and usually means too much soda, or steaming on well after the dhokla had set. Fifteen minutes is enough for a one-inch layer, and longer only tightens it. Put a knife into the centre, and the moment it comes out clean, take it off the heat.
Why is khaman yellow and dhokla white?
Because they are two different things. Khaman is made from besan, that is chana dal flour, with turmeric in the batter, and it is raised with Eno or soda rather than left to ferment. Dhokla, the sour white one, is made from rice and chana dal ground together and fermented, with rice in the larger share and little or no turmeric, so it sets off-white. The yellow also looks brighter in khaman than the same turmeric would look elsewhere, because turmeric shifts towards orange in alkaline surroundings and soda makes the batter alkaline. Plenty of households and shops use the two names loosely, and in everyday speech that is not wrong. But the test is easy — if it ferments overnight and comes out white and faintly sour, it is dhokla; if the batter is ready in ten minutes and comes out yellow, it is khaman.
How much water goes in the dhokliya, and how long do I steam?
Put two to three inches of water in the steamer — enough that it will not boil dry in twenty minutes, but low enough that the thali never touches it. Bring it to a full rolling boil before the batter goes in, not a simmer, because the strong steam of the first two minutes is what sets the surface with the bubbles still in it. A one-inch layer of khaman takes twelve to fifteen minutes on a medium-high flame; a thicker layer or a deep thali can take twenty. Test the centre with a knife or a toothpick — clean means done, wet batter means another three minutes. Tie a cloth under the lid or set the lid slightly tilted so condensation does not drip on top and leave patches. There is one real mistake: lifting the lid in the first five minutes. The steam pressure drops and the half-set batter falls.
What ratio for idli and dosa batter, and how should I grind it?
For idli, four parts idli rice or parboiled rice to one part urad dal, with half a teaspoon of methi seeds in with the dal. For dosa, go to three parts rice to one part dal, which gives a batter that spreads thin and crisps. Soak rice and dal separately for four to six hours, then grind the dal first with cold water until it is white, fluffy and doubled in volume. This is the step where the air goes in, so do not rush it and do not let the grinder heat up. Grind the rice afterwards, slightly grainy like fine rava for idli and smoother for dosa. Combine the two by hand rather than in the grinder, and add salt before fermenting. The usual mistake is grinding everything together into one smooth paste: the urad never traps air that way, and the idlis stay flat however long you ferment them.
The batter has gone too sour. Can it be saved?
Sourness cannot be taken out, only balanced or diluted, so stop trying to reverse it and decide what to do with it instead. What you are tasting is lactic acid the bacteria have already made, and nothing pulls it back out. For dosa, a slightly over-fermented batter is genuinely good — it browns better and tastes fuller. For idli or dhokla, stir a quarter to half a cup of rice flour or fine rava with a little water into two cups of batter and leave it half an hour; adding unfermented bulk brings the sourness down. A pinch of soda just before steaming will also lift it and blunt the edge, but a full spoon gives a soapy taste and yellow idlis. Once the batter is where you want it, move it to the fridge; cold does not stop fermentation but slows it enough to hold a batter three or four days.
The batter has not fermented at all. What do I do now?
Before anything else, give it more time in a warmer place, because an unfermented batter is usually only cold, not dead. Stand the vessel in water at around 40 degrees — warm to the hand but not hot enough to hurt — or keep it in the oven with the bulb on, and check every two hours. Two spoonfuls of a well-fermented batter, or two spoonfuls of thick sour curd, stirred in will often get it moving within four or five hours. A teaspoon of sugar gives the culture something quick to eat. If you have to cook now, treat it as an unfermented batter and raise it chemically: stir in a teaspoon of Eno, or three-quarters of a teaspoon of soda with lemon juice, just before steaming. The dhokla will be decent, though the fermented sour note will be missing. Do not add extra salt hoping to help — heavy salt slows the culture down.
Why does the same batter behave differently every time?
Because the culture is wild rather than bought, and almost everything about the day changes it. The main variable is temperature — five degrees either way can double or halve the time. Next is the dal: urad or chana dal that has sat in a shop for a year ferments slowly and weakly, while dal from a new crop is lively. Then the water, since heavily chlorinated tap water slows the bacteria, which is why many households grind with filtered water. Then how much air the grinding trapped, how much salt went in, how humid the day is, and even the vessel, since steel, clay and plastic hold heat differently. None of this is a flaw in your method. The practical conclusion is simple: stop trusting the clock, mark the starting level on the vessel, and judge every batch by its rise, its bubbles and its smell.