Appears in
Oxford Companion to Food

By Alan Davidson

Published 2014

  • About

kefir originated in the Caucasian mountains and is one of the oldest known cultured milk products. It differs from other such products in that its fermentation is sustained by what are known as kefir grains. When immersed in milk, these yellowish, gelatinous granules swell and turn white, and initiate the fermenting process.

The kefir grains vary in size from something like a wheat grain to something large enough to be described (quite incorrectly, it need hardly be said) as a ‘mushroom’. In fact, they are not single organisms but conglomerations formed from the sediment which is created in kefir by the active micro-organisms. This sediment contains bits of coagulated milk protein, with live cultures of various Streptococci and Lactobacilli and a yeast described as Saccharomyces kefir, and other miscellaneous detritus. It is apt to clump; thus, when kefir is made in a skin bottle or round-bottomed container which is agitated (as by being attached to a nomad’s saddle) the sediment rolls into balls.