Make your own organic milk kefir for a fraction of the cost that you would pay in the grocery store. These easy to use heirloom kefir grains can keep indefinitely as long as you save some starter for your next batch. Kefir is easy to digest and choked full of an array of probiotics that have many health benefits. If you are lactose intolerant you can use water kefir grains to make fermented kefir juice.