Kefir

Kefir (pronounced /kəˈfɪər/ kə-FEER) (or alternatively kefīrs, keefir, kephir, kewra, talai, mudu kekiya, milk kefir, búlgaros) is a fermented milk drink made with kefir grains and is believed to have its origins in the Caucasian mountains of the former USSR. It is prepared by inoculating cow, goat, or sheep's milk with kefir grains. Traditional kefir was made in skin bags that were hung near a doorway; the bag would be knocked by anyone passing through the doorway to help keep the milk and kefir grains well mixed.