Kashk and Persian fermented dairy

Kashk (Persian: کشک) is a dried fermented dairy product central to Persian cuisine, produced by draining yogurt, fermenting the resulting whey, and drying it into solid balls or a dehydrated paste. The process begins with yogurt (mast) that is strained to remove liquid whey; the whey is then fermented, salted, and cooked until thickened, then shaped into balls or spread into sheets and sun-dried. To use, kashk is reconstituted with water and often blended into a smooth, tangy liquid. This technique preserves dairy for months without refrigeration, a traditional method in Iran’s arid climate.

Kashk belongs to a family of Persian fermented dairy products: mast (yogurt), doogh (a salted yogurt drink, often carbonated), and lavashak (fruit leather, made by drying fruit purée, not dairy). The term kashk also appears in Central Asian and Levantine cuisines, but Persian kashk is distinct for its whey base and use in savory dishes.

Key dishes defined by kashk include kashk-e bademjan (eggplant dip with sautéed eggplant, caramelized onions, and kashk), ash-e reshteh (noodle soup garnished with kashk, mint, and fried onions), and halim (wheat porridge with shredded meat, topped with kashk and cinnamon). In these dishes, kashk provides a tangy, umami-rich depth that balances rich or starchy ingredients.

Regional sourcing: The city of Khoy in West Azerbaijan province is historically renowned for high-quality kashk, produced from sheep’s or goat’s milk. Today, industrial kashk is widely sold as a paste or powder in jars, while traditional solid kashk balls remain available in Iranian markets and diaspora communities, including Tehrangeles (Westwood, Los Angeles), the largest Persian-American population center.

Dietary notes: Kashk is dairy-derived, containing milk proteins and lactose; it is not vegan. It is considered kosher-dairy (chalav Yisrael status depends on the milk source and supervision; traditional kashk from sheep or goat milk may not meet modern chalav Yisrael standards without certification). Kashk is generally gluten-free, but commercial blends may include wheat flour as a thickener, check labels. It is not halal if rennet from non-halal animals is used, though traditional Persian kashk typically uses microbial or vegetarian rennet.