About a week ago the New York Times ran a story on making your own yogurt. It’s easy. I won’t say that it ‘boils down to this’ because boiling and living foods don’t go together very well. Here’s how it develops:
Heat the fresh milk at 180 to 190 degrees, or to the point that it’s steaming and beginning to form bubbles. The heat alters the milk’s whey proteins and helps create a finer, denser consistency.
Let the milk cool to around 115 to 120 degrees, somewhere between very warm and hot. For each quart of milk, stir in two tablespoons of yogurt, either store-bought or from your last batch, thinning it first with a little of the milk.
Then put the milk in a warm jar or container or an insulated bottle, cover it, and keep the milk still and warm until it sets, usually in about four hours. I simply swaddle my quart jar in several kitchen towels. You can also put the container in an oven with the light bulb on.
There are some more specific serving suggestions and recipes in there, plus some great info about what causes milk to harden up as it turns into yogurt. Check it out!