Like yogurt it is fermented milk. Unlike yogurt, it is much stronger, greater number of good bacterias and yeasts. It is liquidy not thick. You can buy it, but it is not effective that way because it has been sitting on the shelf too long. Look up "Dom's Kefir Site" on google. You can but grains through him. Just pour milk over the grains and the kefir will grow like crazy. You have to follow the directions thougjh, after travelling through the mail it will take 3-4 days for the grains to recover. et the book "Nourishing Traditions" by Sally Fallon or "Body Ecology Diet" book. It is best to make it your self. It is strongr that way and all you must buy is milk. You can use any type of milk, or soy milk, or coconut milk...whatever you want. Many recipes in nourishing trad book.