Step 1 – Soaking
Rinse and soak rice and dal in separate bowls as both require different grinding times and consistency. The batter won’t be smooth if both of these soaked together. So it’s important to soak rice and lentils in different bowls.
Add fenugreek seeds to the bowl of dal for soaking. Let it soak for 6 – 8 hours or overnight.
Step 2 – Blending
Remove from water and transfer rice to a high speed blender. Add little cold water (~ ½ cup). Cold water is necessary to prevent the heating of dal batter which may hinder the fermentation process. Blend it to smooth consistency.
Repeat the same with urad dal. Add little water to the blender and blend to smooth batter.
Now pour the batter into a large bowl and mix the batter well. Give it a nice stir. Add non-iodized salt (rock salt) for better fermentation. If the mixture is too thick add ¼ - ½ cup water more for a thick flowing consistency.
For a better fermentation process, mix the batter well in a spatula which incorporates more air into the batter for a natural fermentation process.
Step 3 – Fermenting in the instant pot
Transfer the batter to a large bowl and place it near warm place for fermentation. Cover it with a lid.
In normal or warm climate/ places, you can ferment the batter on the countertop. It can take anywhere from 8 – 12 hours to ferment the batter. It also depends on the outside temperature.
Fermenting batter in cold places or cold weather is difficult than warmer ones. But with help of instant pot or oven this is much easier than the traditional way.
To ferment the batter in instant pot, transfer the prepared batter to the instant pot steel insert. Place it inside and start with yogurt mode. Set timer for 12 hours. Cover instant pot with a glass lid and let the batter ferment.
After 12 hours, when the batter is fermented well, remove and store the batter in another air-tight container. The idly batter is now ready to make idli. Also, you may refrigerate this for up to a week.