छाछ

Chaas is spiced buttermilk, the thin sour liquid remaining after cream is churned to make butter, seasoned with salt, roasted cumin, ginger, and green chili. The Hindi and Gujarati word chaas derives from the Sanskrit chhas or takra, terms documented in the Sushruta Samhita around 600 BCE as therapeutic preparations for digestive ailments. Takra was the more formal medical term; chhas described the everyday kitchen product. The distinction between thin buttermilk (chaas) and thick cultured yogurt drink (lassi) is maintained consistently in Sanskrit and vernacular medical texts from the first millennium CE onward.

The Ayurvedic texts are specific about takra's properties: they classify it as laghu (light) and agni-deepana (fire-enhancing for digestion), recommended after meals in summer and for treating conditions ranging from anemia to hemorrhoids. Charaka, writing around the second century CE, calls takra the nectar for human beings and says it does not cause heaviness even when drunk in large quantities. This medical framework gave chaas a cultural legitimacy beyond just refreshment. The spice additions, particularly cumin and ginger, were not taste preferences but therapeutic intensifiers chosen to amplify the digestive benefits.

The Gujarati version of chaas is thinner and more aggressively seasoned than North Indian variants, often including a small tempering of mustard seeds and curry leaves fried in ghee before being stirred in. This technique (the tadka or vaghar) reflects the Gujarati culinary habit of adding a hot fat temper to cold dishes just before serving, a contrast that wakes up dormant flavors. The Rajasthani version leans on the sourness of the buttermilk itself, using minimal spicing. Maharashtra's taak, the local name for the same drink, sometimes includes a pinch of asafoetida, each variant recognizable as the same category but distinctly regional.

Chaas became commercially significant in India in the late twentieth century when dairy cooperatives, particularly Amul in Gujarat, began bottling it for mass distribution. The packaged Amul Chaas launched in the 1990s and became one of the cooperative's most successful non-cheese products, reaching markets in South Asia, the Middle East, and the Indian diaspora globally. The drink arrived on British supermarket shelves under the name buttermilk in some stores, though this is technically inaccurate: Western buttermilk is cultured, not churned, and lacks the spicing that defines chaas.