Idlis made with thick batter are very tough.
I use idli rice these days from Indian stores and idlies come out great!.
On my very first try, the idlis came out fantastic — totally soft, much much better than store bought batter and I could guarantee the quality of ingredients as well as much cheaper to make.
I sprinkle water every five minutes and totally grind the dal for about 30 mins.
I have to thank you!! You can see so many bubbles in the light, fluffy batter.