Homemade yogurt with instant non-fat powdered milk

Mix 1 quart warm water (like for yeast) with 1 1/3 dry milk powder
Add 1/4 cup yogurt with active cultures (use plain) and mix well.
Pour into quart or 2 quart jars and cover with plastic lids. Place the yogurt in a picnic cooler with two quart juice or 1/2 galloon milk jugs filled with very hot water. Alternate yogurt jars with hot water jugs in cooler. Cover cooler with towel and let stand for 3 hours. Yogurt is ready when it pulls away from jar. If not ready in 3 hours, check every half hour. If you leave it too long yogurt will curdle and smell yeasty. You can still use this for cheese by straining through cheesecloth.
Honestly,  it has always taken longer for me and I have had less luck with this recipe. Maybe my tap water just doesn't get hot enough. But I have know others that prefer this recipe and have had great success and it is a great way to rotate your powdered milk. Good luck!