Kumis

Kumis (/ˈkuːmɪs/ KOO-mis, rarely /ˈkʌmɪs/ KUM-is), alternatively spelled coumis or kumyz, also known as airag (/ˈaɪræɡ/ EYE-rag), is a traditional fermented dairy product made from mare milk. The drink is important to the peoples of the Central and East Asian steppes, of Turkic and Mongolic origin: Kazakhs, Bashkirs, Kalmyks, Kyrgyz, Mongols, and Yakuts. Kumis was historically consumed by the Khitans, Jurchens, Magyars, and Han Chinese of North China as well.

Kumis is a dairy product similar to kefir, but is produced from a liquid starter culture, in contrast to the solid kefir "grains". Because mare's milk contains more sugars than cow's or goat's milk, when fermented, kumis has a higher, though still mild, alcohol content compared to kefir.

Even in the areas of the world where kumis is popular today, mare's milk remains a very limited commodity. Industrial-scale production, therefore, generally uses cow's milk, which is richer in fat and protein, but lower in lactose than the milk from a horse. Before fermentation, the cow's milk is fortified in one of several ways. Sucrose may be added to allow a comparable fermentation. Another technique adds modified whey to better approximate the composition of mare's milk.