Kefir dates back many centuries to the shepherds of the Caucasus mountains. They discovered that fresh milk carried in leather pouches would occasionally ferment into an effervescent beverage.In the Caucasian Mountains, legend has it that the resulting kefir "grains" (not a true grain-but a combined culture of yeast and bacteria) were a gift to the people from Mohammed, who instructed them on how to use the grains. Mohammed strictly forbade them from giving away the secret of kefir preparation to other people, or pass anyone kefir grains, because they would lose their "magic strength." This legend explains why kefir grains and the method for kefir preparation have been surrounded by mystery for so long. In fact, there is an incredible tale of intrigue starring a beautiful woman, Irina Sakharova, who stole the kefir grains from a prince for Russia, which is perhaps the only reason the world knows of kefir today.