Making your own yogurt is a simple process. You're basically just heating and cooling milk. But you have to closely control the temperature. Maintaining specific temperatures is the most important part of making yogurt at home. The other big deal is protecting everything from contamination. You need to be careful to keep out bacteria that you don't want in there.
You'll want to gather up the following equipment to get started:
- Double boiler: A large pot with a smaller pot that fits inside it; for our recipe, the small pot should hold at least 4 quarts
- Large spoon: Metal or plastic (because you have to be able to sterilize it)
- Food thermometer: Preferably one that can be attached to a clip so you can secure it to the double boiler
- Incubator: A closed container that can maintain a fairly tight temperature range; this is what a store-bought yogurt maker does, but you can also use either a gas oven or a picnic cooler. We're going to use the oven method -- which means we also need an oven thermometer. (See Fias Co Farm's yogurt page for a description of other incubation methods.)
- Measuring cup/spoons
And you should collect the following ingredients:
- One quart of milk: Whole, skim or low fat, depending on your preference
- Yogurt starter: Either a small container of plain yogurt (Dannon plain, with the latest expiration date you can find, is recommended) or a package of yogurt starter cultures
- Nonfat dry milk powder: 1/3 cup if you're using whole or low-fat milk; 2/3 cup if you're using skim milk
- Optional: Sugar, honey or fruit for sweetness, vanilla or coffee for flavor, gelatin for thicker yogurt
Once you've got all of this in your kitchen, it's time to start making yogurt. In this recipe, adapted from Making Yogurt at Home by Barbara Willenberg of the Department of Food Science and Human Nutrition at the University of Missouri, you're going to create a basic, tart, "plain" yogurt.
First up: sterilization.