Wash and Soak rice, all the dals with red chillies and ginger for 3-5 hours.
After throughly washing the rice and lentils, add water to almost half way above the rice and lentils.
The water is full of nutrition and you don't want to drain the nutritious water after it is soaked.
Put the mix in 2 batches in to a blender and Grind to a coarse consistency ( not too soft not too grainy).
Add the water the mix soaked in as needed.
Add salt and asafoetida and mix well.
Traditionally Adai batter is not fermented and can be used right away. So Adai batter is ready for use right away.
I do ferment mine because that is how I like it.
Add chopped onions, coriander leaves and curry leaves right before making the Adai.