Kefir milk grains for sale. Kefir milk grains are a mother culture of probiotics which ferment milk and turn it into kefir(drinkable yoghurt). These grains will double in size after two weeks of use. Preferred milk to use are the local fresh milk. Kefir has many nutritional and health benefits and is suitable for individuals with lactose intolerance, crohns disease and irritable bowels.