What is Kefir

Kefir is a fermented milk drink made with kefir grains. It is prepared by inoculating cow, goat, or sheep's milk with kefir grains.

Kefir grains will successfully ferment the milk from most mammals, and will continue to grow in such milk. Typical milks used include cow, goat, and sheep, each with varying organoleptic and nutritional qualities. Raw milk has been traditionally used.

In addition, kefir grains will ferment milk substitutes such as soy milk, rice milk, and coconut milk, as well as other sugary liquids including fruit juice, coconut water, beer wort and ginger beer. However, the kefir grains may cease growing if the medium used does not contain all the growth factors required by the bacteria.

Milk sugar is, however, not essential for the synthesis of the polysaccharide that makes up the grains (kefiran), and studies have demonstrated that rice hydrolysate is a suitable alternative medium. Additionally, it has been shown that kefir grains will reproduce when fermenting soy milk, although they will change in appearance and size due to the differing proteins available to them.