Kumis

Kumis is a fermented dairy product traditionally made from mare milk or donkey milk. The drink remains important to the peoples of the Central Asian steppes, of Turkic and Mongol origin: Kazakhs, Bashkirs, Kalmyks, Kyrgyz, Mongols, and Yakuts. Kumis was historically consumed by the Khitans, Jurchens, Hungarians, 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.

Source: Wikipedia