2 cups idli rice + 2 cups water to soak
1/2 cup urad dal + 1 cup water to soak
1/4 cup thick poha (flattened rice) + 1 cup water to soak
1/2 teaspoon methi (fenugreek) seeds
2 teaspoons sea salt (for every 1 cup of dry, add 1 tsp. salt)
Water to steam idli
Soaking rice, dal and poha
Rinse rice, dal and poha SEPERATELY. Rinse until water runs clear.
Add rice to a bowl and cover with water. Use filtered or bottled water to soak. If using tap water, allow water to sit out on the counter for 2 hours so the chlorine evaporates from the water. Note: I've used tap water and my batter does not ferment properly.
Add urad dal and methi seeds (the methi seeds help to promote fermentation) to a separate bowl and cover with water. Use filtered or bottled water to soak.
Soak poha and water.
Soak rice, dal and poha separately for 4-5 hours. The reason for soaking separately is because they grind differently and you want the urad dal to be as smooth as possible whereas, the rice will still be a little gritty. Mixing these two textures together after grinding each is what makes a perfect batter.
I use a Vitamix to grind because I get consistent results. Note: You can use any type of blender that you have. The trick is grinding to the proper consistency.
Drain the urad dal and reserve the water. You will need to use this water to add when grinding to make a smooth, fluffy batter.
Grind the urad dal and methi seeds starting with 1/4 cup of the reserved water. Add more water to get a smooth consistency but you want a thick batter. Do not add too much water.
Remove the urad dal batter to a large bowl and set aside.
Drain the idli rice and reserve the water.
Grind the idle rice in batches to make a smooth batter. Start with 1/4 cup water and continue to add as necessary to make a smooth batter. Add poha and grind to combine. You do not want this mixture to be too runny, you want a thick consistency with a little grit. Once you have a smooth rice/poha batter, add this mixture to the ground urad dal batter.
Use your hands to mix the batter together. Something about using your hands that makes the batter ferment.
Cover and let the batter ferment (In cooler months, I use my oven with the light on for about 2 hours and then I turn off the oven light and check the batter in the morning), for 8-10 hours or longer, if required. The batter should double in size and rise with some bubbles in it. You can tell if the fermentation is ready if you take a small spoonful of batter and drop it into a cup of water. If the batter floats, it is ready.
If your batter does not float and you've followed the steps above, cover and place back in the oven with the light on for a bit longer - it could take another 2 hours.
Add salt after fermentation. Stir well to combine.
Using an idli mould - grease the moulds (I spray mine with olive oil) and pour batter into each mould. Steam for 7-8 minutes. I use a regular large pot with a lid to steam. I do not use my pressure cooker but you can do it like that too.
Serve idli with Sambar and Chutney.
Batter can be stored in the refrigerator for up to 4 days. I have also added water to this batter to thin it out and I make Dosas the next day.
You can add 1/2 tsp. Baking soda after fermentation if your batter seems flat.