Rinse and soak the above ingredients in water for about 2-3 hours.Then grind in a blender (with adding water in steps).Add salt and keep it aside (to get sour)for 12 hours. Take idli plates and place a drop of oil in each idli mould and spread it over the entire mould. Heat 2 cups of water in a large vessel or pressure cooker and place the filled idli plates and cover with lid. Heat in high for about 20 minutes. Remove the plates from the vessel and remove the idlis.Pour 2 tsp of sesame oil while serving. Side dish - Sambar, dosai milagai powder, and coconut chutney While using pressure cooker for making idlis, the steam hole should not be covered by adding the cooker weight. Steam should escape freely.