This is the most quintessential ingredient of almost all South Indian homes. No home's fridge is devoid of this.
Boiled rice / tiffin rice – 5 cups
Urad dal – 1 cup
Rock Salt – to taste
Water – to grind
The ratio of rice and dal is 5:1. clean and wash rice and dal separately for 2 – 3 times . Soak them in water separately for at least 4 hours.
In a wet grinder or a mixer grind the rice first. Never grind the rice to a smooth paste but the texture should be little grainy as though you are feeling castor sugar. Transfer to a big container.
Grind the urad dal along with the soaked water in the same grinder next. Try and add little water as possible. Grind it to a smooth paste. The consistency is that when you take a spoon full of the dal batter and drop it in a cup of water the batter should float on top of the water and not sink right in. transfer this also to the ground rice.
Add salt, usually a handful, mix well and let it be on the kitchen counter over night for fermentation.
The next day mix it lightly to let the air out. Refrigerate this batter and use when needed.