Idli

A precursor of the modern idli is mentioned in several ancient Indian works. Vaddaradhane, a 920 CE Kannada language work by Shivakotiacharya mentions "iddalige", prepared only from a black gram batter. Chavundaraya II, the author of the earliest available Kannada encyclopedia, Lokopakara (c.1025 CE), describes the preparation of this food by soaking black gram in buttermilk, ground to a fine paste, and mixed with the clear water of curd and spices.[1] The Western Chalukya king and scholar Someshwara III, reigning in the area now called Karnataka, included an idli recipe in his encyclopedia, Manasollasa (1130 CE). This Sanskrit-language work describes the food as iḍḍarikā. In Karnataka, the Idli in 1235 CE is described as being "light, like coins of high value", which is not suggestive of a rice base.[2] The food prepared using this recipe is now called uddina idli in Karnataka.

The recipe mentioned in these ancient Indian works leaves out three key aspects of the modern idli recipe: the use of rice (not just black gram), the long fermentation of the mix, and the steaming for fluffiness. The references to the modern recipe appear in the Indian works only after 1250 CE. Food historian K. T. Achaya speculates that the modern idli recipe might have originated in present-day Indonesia, which has a long tradition of fermented food. According to him, the cooks employed by the Hindu kings of the Indianised kingdoms might have invented the steamed idli there, and brought the recipe back to India during 800–1200 CE.[3][4] Achaya mentioned an Indonesian dish called "kedli", which according to him, was like an idli.[5][3] However, Janaki Lenin was unable to find any recipe for an Indonesian dish by this name.[6] According to food historian Colleen Taylor Sen the fermentation process of idli batter is natural process that was discovered independently in India, since nearly all cultures use fermentation in some form.[7]

Gujarati historians believe that it was Saurashtrian textile merchants who introduced idli to South India during the 10th and 12th centuries. There are even claims that a mix of rice and black gram ground together and later steamed to form cakes had its origins in Gujarat.[8] The Gujarati work Varṇaka Samuccaya (1520 CE) mentions idli as idari, and also mentions its local adaptation idada (a non-fermented version of dhokla).[9]

The earliest extant Tamil work to mention idli (as itali) is Maccapuranam, dated to the 17th century.[10][11] In 2015, Chennai-based Idli caterer Eniyavan started celebrating 30 March as the "World Idli Day".[12]

To make Idli, four parts uncooked rice (idli rice or parboiled rice) to one part whole white lentil (black gram, Vigna mungo) are soaked separately for at least four hours to six hours or overnight. Optionally spices such as fenugreek seeds can be added at the time of soaking for additional flavour. Once done soaking, the lentils are ground to a fine paste and the rice is separately coarsely ground, then they are combined. Next, the mixture is left to ferment overnight during which its volume will more than double. After fermentation some of the batter may be kept as a starter culture for the next batch. The finished idli batter is put into greased moulds of an idli tray or "tree" for steaming. The perforated molds allow the idlis to be cooked evenly. The tree holds the trays above the level of boiling water in a pot, and the pot is covered until the idlis are done (about 10–25 minutes, depending on size). A more traditional method is to use leaves instead of moulds.[14]

• Making idlis
• 
  Key ingredients used are rice and black gram.
• 
  Idli batter
• 
  Idli mold
• 
  Batter poured into the mold
• 
  Several molds stacked over another
• 
  Idli steaming in cooker
• 
  Cooked idli
• 
  Molds removed from cooker
• 
  Idlis ready to eat

Serving

Since plain idlis are mild in taste, a condiment is considered essential. Idlis are often served with chutneys (coconut based), sambar and Medu vada. However, this varies greatly by region and personal taste, it is also often served with kaara chutney (onion based) or spicy fish curries. The dry spice mixture podi is convenient while travelling.

Idli served with coconut chutney, sambar and medu vada on banana leaf.

Fermentation of idli batter results in both leavening caused by the generation of carbon dioxide as well as an increase in acidity. This fermentation is performed by lactic acid bacteria especially the heterofermentative strain Leuconostoc mesenteroides and the homofermantative strain Enterococcus faecalis (formerly classified as Streptococcus faecalis). Heterofermantative lactic acid bacteria such as L. mesenteroides generate both lactic acid as well as carbon dioxide whereas homofermantative lactic acid bacteria only generate lactic acid.

Both L. mesenteroides and E. faecalis are predominantly delivered to the batter by the black gram. Both strains start multiplying while the grains are soaking and continue to do so after grinding.

L. mesenteroides tolerates high concentrations of salt unlike most other bacteria. Hence the salt in the batter and the ongoing generation of lactic acid both suppress the growth of other undesirable micro-organisms.[21][22]

March 30 is celebrated as World Idli Day.[23] It was first celebrated in 2015 at Chennai.[24]

• K. T. Achaya (12 May 1994). Indian Food: A Historical Companion. Oxford University Press, USA. ISBN 978-0-19-563448-8.
• Devi, Yamuna (1987). Lord Krishna's Cuisine: The Art of Indian Vegetarian Cooking, Dutton. ISBN 0-525-24564-2.
• Edward R. Farnworth (2003). Handbook of Fermented Functional Foods. CRC Press. ISBN 978-0-8493-1372-1.
• Jaffrey, Madhur (1988). A Taste of India, Atheneum. ISBN 0-689-70726-6
• Rau, Santha Rama (1969). The Cooking of India, Time-Life Books.