Wash and soak the millet and the lentils together for 4 hours minimum. I usually soak them around lunch 2 pm for 8pm dinnner. I grind it around 7 pm and rest it for 30 minutes before making it for dinner.
After the minimum 4 hours of soaking time, drain the excess water, take the contents into a mixer jar along with red chilies, curry and coriander leaves, coconut, ginger and grind it to a batter. It usually needs around ½ - ¾ cup of water to grind well.
Addition of coconut though is optional, it adds a great flavor to the adai,
Remove the batter to another vessel, add salt and mix well. Check the consistency, it should be little thick like idly batter.
Some might prefer the adai batter to dosa batter consistency. If yes, then add aother ¼ cup of water to it and mix well.
Let the batter rest for 30 minutes for the spices to mingle well.