1 gallon nonfat milk 1 cup nonfat plain yogurt with live cultures 1.5 cups powdered dry milk
The whey liquid will rise to the top during the process. In the morning, you may pour the whey off to make ricotta cheese, or you can stir it back in. Nonfat milk makes less whey since the protein usually needs more fat to separate during culture growth. The recipe makes 17 1 cup servings of 117 calories each, or 33 1/2 cup servings at 60 calories each. Since yogurt is so expensive in the stores, I make my own, and once you have your own, you may use your own as the nonfat yogurt with live cultures.
Put milk in crockpot on high and bring just to a boil (you really only have to bring it to 180 degrees, but I am always running amuck and forget to check on it). Take crock out of heater pot and leave on counter, allowing milk to slowly reduce heat back to 115 degrees as measured by thermometer. Add yogurt and powdered milk. Stir until well-combined. Then place in oven (do not turn oven on) overnight (12-24 hours to grow cultures). In morning, pour into sealed containers and refrigerate.