Milk kefir is an easy sell for anyone who loves yogurt, which I most definitely do. KefirsmoothieprobioticsAll you need is a teaspoon of active kefir grains and a cup of whole milk. Milk kefir is a fermented dairy product similar in many ways to yogurt and buttermilk. It’s how kefir is cultured that makes it really unique — instead of heating the milk, adding a culture, and keeping it warm as you do with yogurt, all you need to make milk kefir are kefir grains.