The good thing about idlis is that they are plain, safe and adaptable to a lot of combinations.
Although the precise history of the modern idli is unknown, it is a very old food in southern Indian cuisine. The first mention of it in writings occurs ca. 920 A.D., and it seems to have started as a dish made only of fermented urad dal. One description ca. 1025 says the lentils were first soaked in buttermilk, and after grinding, seasoned with pepper, coriander, cumin and asafoetida. The king and scholar Someshwara III, reigning in the area now called Karnataka, included an idli recipe in his encyclopedia, the Manasollasa, written in Sanskrit ca. 1130 A.D. There is no known record of rice being added until some time in the 17th century. It may have been found that the rice helped speed the fermentation process. Although the idli changed in ingredients, the preparation process and the name remained the same (Wiki).
Bacterial fermentation causes the batter to swell thus enabling fluffy idlis to create quite a fan following.
Idli is a small, white acid-leavened and steamed cake prepared by bacterial fermentation of a thick batter prepared from carefully washed rice and dehulled black gram dhal. The rice is coarsely ground and the black gram is finely ground. Dosa batter is very similar to idli batter, except that the rice and black gram are finely ground (FAQ.org).
Perhaps Idli is the most sophisticated dish of its times uninfluenced by any foreign invasion. It originated in South India. The Rice and Urd Dal (Split Black beans) are soaked overnight, ground and let the mixture ferment overnight and then making dumplings in steam. According to age old myths, heavens send blessing through the Palm trees to the hands of the woman to cause fermentation. We know now that the fermentation is the result of air-born wild yeast, and has nothing to do with the Palm trees (Indiacurry).
While the belief that heavenly blessing to the hands of a woman causes fermentation may be archaic, it is still amazing how no two idli batters are the same. The maker does have magic - remember all those dialogues on several mouths about "amma oda idli" (my mother's idlis)?
There are umpteen idli places in Chennai - from steaming idlis served on the roadside to restaurants that use idlis as a marketing trump card. Soon after 'Murugan Idli' opened a couple of restaurants in Chennai, there was a 'Valli Idli' restaurant. The country of the original copy cats indeed :)
Finally, an idli addict's fantasy of starting an only-idli restaurant.
By the way, what is your favourite idli combination? I like them with coriander chutney or sambhar or tamarind chutney (other than curd of course!).