Yogurt (dahi) and buttermilk (chaas/more)

Writings from as early as 2100 B.C. describe the magic of these tart ingredients. They lend not only sourness to our karis and kadhies but also digestive comfort. It is customary, even now, to end a meal with either plain yogurt mixed with rice or a glass of thin buttermilk.

Yogurt has multiple personalities, and all its incarnations affect curries in different ways. Take the example of Slow-Cooked Baby Potatoes in a Yogurt-Fennel Sauce, where yogurt is “stir-fried” long enough to evaporate all its moisture, turning the curd pellets very sharp-tasting. When used as a base for marinating meats, yogurt not only imparts a pleasant tartness to the curry but balances out the heat of the chiles. It also tenderizes the meat with its acidity and enzymes. When dolloped atop finished dishes, yogurt blankets the mélange with a creamy, cooling presence.