Kefir
Kefir is a cultured dairy product similar to yogurt, but has a greater probiotic content than yogurt. It is simply made, but requires either the purchase of kefir starter packs or kefir grains. The kefir grains can be stored and reused.
The greatest resource for information on kefir, how it is made, sources of kefir grains, and troubleshooting that we have found is at Dom’s Kefir. Even though Dom is located outside the US, he provides information on his site for locations in the US to obtain kefir grains.
Our family enjoys using kefir to make smoothies for breakfast or as a snack. We have also recently discovered that it is wonderful in pancakes when our supply of buttermilk is running low.