Vermicelli is a type of pasta, round in section and somewhat thinner than spaghetti. Rice vermicelli is thin noodles made from rice, sometimes also known as rice noodles or rice sticks. Rice vermicelli are a part of several Asian cuisines, where they are often eaten as part of a soup dish, stir fry, or salad. Rice vermicelli is particularly prominent in the cuisines of People’s Republic of China, Taiwan and Southeast Asia. It is also feature in the cuisines of South India and Sri Lanka, where they are called sevai or idiappam (the latter also called “string hoppers. Sevai is made out of other food grains like wheat, ragi, etc. also are increasingly becoming popular.Sevai is popular as a breakfast/dinner food and is considered easily digestible as it can be made with less or no oil, and it is steamed. Home made Sevai is often made from 100% rice (with water and salt, of course) where as dry rice sticks may often have some additives like tapioca, corn starch, etc.
Instant rice noodles have other additives like Wheat gluten, Guar gum, edible starch, etc.
Sevai/Santhakai is mostly made fresh starting from rice grains. It is also prepared from a dried Sevai packs (or rice sticks) like the instant ones in the Asian grocery stores.
Sevai is often flavoured with Lemon, Tamarind, Tomato, Coconut, etc. and tastes best when served warm. Popular accompaniments for plain sevai are sweetened coconut milk, more-kuzhambu, several vegetable kormas and mutton/chicken/fish korma.