Kefir is a tangy, probiotic-rich drink made by fermenting cow’s or goat’s milk or water with a culture starter called kefir grains — small clusters of bacteria and yeast that resemble tiny cauliflower ...

Kefir was first documented as a health supplement in the 1880s, but in the last decade it has gained worldwide attention. Kefir is generally included in the category of natural probiotics, with the ...