I have been making yogurt this way for many, many years…
All equipment should be very clean.
I recommend starting this in the early morning
For one quart of yogurt (I have multiplied this up to 4 times to make more, as needed), Use one and a third cups of dry nonfat milk powder (or a one quart pouch) and one quart of very warm but not too hot water. If you are unsure and want to use a candy thermometer, this is about 160 to 180 degrees. Blend well in a bowl with a wire whisk. Allow milk to cool a bit to a little above body temperature (110 degrees is ideal). Remove 2 cups cooled warm milk into a small bowl. Slowly add and whisk in about 1/2 cup plain cultured yogurt (for one or two quarts of milk) or about one cup for up for three quarts or a gallon of milk. Blend slowly and well. Return the contents of the small bowl, to the larger bowl of cooled warm milk and mix gently together.
Pour all the milk mixture into a clean glass jar, size depends on quantity of milk. Place the jar in the center of a large metal pot or kettle with high sides. Wrap the outside of the jar well with enough towels to insulate it and hold it snug in the kettle. In the cold weather, I place the kettle behind or beside the wood stove and keep it there all day. In warm weather I place the kettle and jar outside in a sunny place and let the heat of the sun do the job. I’ve even heard of people using a Crock pot on a low setting to do this. Anywhere that will hold the consistent warmth for several hours will work. Carefully turn the kettle 1/3 or 1/2 turn every few hours, to keep the heat consistent.
The glass should feel very warm to the touch but not too hot to touch. You want to insulate the yogurt-to-be mixture while it incubates. Don’t bump the jar, just let it be. After six to ten hours, the contents of the jar should appear thicker when you lift it and tilt it slightly. Remove it from the kettle and place it in the refrigerator over night. It should be thicker and creamy by morning.
Not necessary but an option: If you want to create Greek-style yogurt, just line a sieve or colander with a double layer of cheese cloth and suspend it above a large bowl. Add the yogurt to the sieve and let it drain for 3 or 4 hours. The resulting thickened (Greek-style) yogurt in the sieve needs to be refrigerated. This process reduces the yogurt by about half, concentrating the protein solids.
I replace some or all of the milk and/or cheese in the following recipes with yogurt, for instance; cheddar Quiche, zucchini Parmesan, scalloped potatoes, tangy cheddar cheese sauce for steamed veggies, creamy tomato soup and lasagna. I also use it in place of sour cream on baked potatoes, tacos and herb dips for crackers and vegetables. It can also be used in any baking recipes calling for buttermilk.
Homemade yogurt make awesome smoothies too.
To make a really simple, tasty and fat-free smoothie, combine the following in a blender:
3/4 cup skim milk yogurt
1/2 cup frozen fruit like berries, peaches, melon, bananas
1/4 cup fruit juice concentrate (not fruit juice cocktail)
1/2 cup cold water
Optional: 1-2 tablespoons of honey or maple syrup
Combine all Ingredients in the Blender
Blend for 20 to 40 seconds until well blended but still very thick and frothy
Makes 2 plus cups of very yummy and satisfying smoothie. This is my liquid lunch of choice in the summer when I am spending the day working in the yard and garden. It is amazingly refreshing and restorative.
Lasagna in the Making with Yogurt
Finished Baked Lasagna
Taco with Yogurt on Top Before it’s Rolled Up