Idlis are very famous breakfast dish from South India. Every state has a different set of ingredients to get fluffy idlis. This is the way we get idlis in Tamil Nadu. Nowadays idli batter is readily available in the market. So it has become very rare to prepare batter at home. Though the batter sold in the stores is highly priced, the taste of idlis can never beat the home made ones. The ingredients used for the batter are parboiled rice and urad dhal. The quantity of urad dhal in the batter decides the fluffiness of idlis. If the urad dhal is less you get hard idlis and if it is more then you get softer but flatter idlis. Grinding the batter has a lot of techniques involved.
There are two types of urad dhal available in the market. Fresh dhal gives a large amount of batter and the older ones give a little less. So while purchasing it is better to ask the salesman about the dhal. But nowadays, in supermarkets we get packed dhal and it is very hard to trace the condition of the dhal. My mom usually prefers older dhal because it tastes nice. So it is important that you do a little experimenting. Start with smaller quantity of rice and dhal. Prepare the batter and prepare idlis out of it. If the idlis are perfect then you can use the same proportion until you finish the dhal. If the idlis are soft but flat, then you need to reduce the amount of urad dhal. If the idlis are harder, then you need to increase the amount of dhal. This surely needs some experience to get it right.
Usually 1cup of rice is used along with 1/4cup of urad dhal. If you are preparing large quantity and will be using the batter for a week, then you can go for 1 kg rice and 250gm of dhal.
Soak rice for 4-5hours. Soak urad dhal for 15minutes(this will give a fluffy batter)
Wash the grinder thoroughly, add the soaked dhal and grind for 15-20minutes until fluffy.
When taken in your hand, you can see a lot of air bubbles in the batter. This makes the batter light and the idlis will come out very soft and porous. Transfer the batter to a large vessel.
Now add the soaked and drained rice to the grinder and add water and grind it to a smooth batter.
Transfer the batter to the vessel containing dhal batter.
Add salt. This is the amount of salt added to 1 kg of rice and 250gm of dhal.
Mix well and cover the vessel. Let it ferment for 8-10hours. The batter will be double the volume.
With a spoon whisk the batter to release air bubbles. When lifted with spoon, the batter should feel light. Use this batter to prepare idlis.