Homemade kefir is a probiotic drink. It’s made using a culture of yeast and bacteria (like a kombucha SCOBY) called, “grains”, a word used to describe the appearance not the ingredients.
Place one tablespoon of milk kefir grains in a quart-size mason jar.
Pour one quart of milk over the kefir grains.
Cover the jar with a cheesecloth or breathable towel, secure with a rubberband. Label the jar with the date and time. Place the jar on the counter. Allow to sit at room temperature for 24 hours.
After 24 hours stir the kefir. It will be thick. There may also be separation, this is normal. Using a strainer, strain the kefir to separate the grains from the milk kefir. Use either a bowl or clean mason jar for the kefir.