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.
Marco Polo mentioned kefir when recounting his travels.
Read more about Kefir: Overview, Production, Preliminary Research, Consumption, Milk Types, Culinary Uses, Possible Origin of Kefir Grains, Other Fermented Dairy Products, Other Fermented Beverages