When you are soaking ingredients for idle or dosai etc., first wash the ingredients thoroughly and then soak them in enough water – do not soak them in either too much or too little water
When you are about to grind, strain all the water by using a Colander. Set this water aside. For grinding use this water (set aside) sprinkling some of it when required – do no add excess water – the idlis will not be very light
After grinding is over, add salt, beat the batter thoroughly – if thick, add some more water, to have a fairly loose batter, unless mentioned otherwise – leave overnight to ferment.
Try to use as much of the water set aside as possible as this water contains nutrients.
If you are making the preparation for breakfast, soak in the evening for about 3-4 hours, then grind the batter and leave overnight to ferment. If you are making the batter for evening tiffing soak ingredients early morning and grind after 2-3 hours, leave aside about 5-6 hours before making.
If the batter has not risen enough and the end product is not very satisfactory, then add a pinch or two of cooking soda to 1/4 cup curds and mix into the batter. Beat thoroughly before making.
Black gram dal for idli should be ground very, very fine – absolutely fluffy – only then will be idli be light. Rice should be ground like rava and both mixed thoroughly. Idle rava sold in grocery stores yield good results.
Do not make idlis with very sour batter – use it instead to make uttappam or paniyaram. Or you could add a little rice flour and make dosai.
Rava idli should be made as soon as you have the batter ready – allowing it to remain for a while will make these idlis hard. If you are making in large quantities, mix with curds just before pouring it into the idli moulds.
Idli moulds should be greased thoroughly with some oil, before pouring the batter – otherwise idlis will not come out in perfect rounds.