First, buy a small container of plain, unflavored, "live" yogurt culture in a grocery store. It's often called "acidophilus" yogurt. Or get a package of the dry culture at a healthfood store.

Heat a pint of milk to 180 degrees and then cool it to 110 degrees. Don't try to just heat it to 110 degrees. It has to be heated to 180 and then cooled to 110.
>Slowly stir in 1/2 teaspoon of the acidophilus yogurt. Don't let the
>temperature of the milk fall below 106 degrees. Don't use more yogurt,
>because if the bacillus gets crowded, it gives a sour, watery product. If you use the dry packaged culture, use the entire package.

Pour the mixture into the yogurt jars. This will make 4 one-half cup

Cover the jars and put them in a warm place where the temperature will be maintained. Yogurt doesn't like to be jostled while it's growing, so be sure to put the jars somewhere where they won't be disturbed for the next 8 hours.

About 8 hours later, check the jars to be sure the yogurt has set. It should be of a custard consistency if you use cow's milk, a little more liquid than that if you use goat's milk.

If it isn't ready, let it sit for awhile longer, checking it every hour. Be SURE the temperature has not fallen below 106 degrees. It will NOT set if the temperature falls below that.When it is ready, refrigerate it immediately.
You can stir in amendments as soon as the yogurt is cold. My family's
favorites are 1/8 tsp lemon or orange extract and 1 pkg Equal and several slices of mandarin orange or 1/8 tsp strawberry extract and 1 pkg Equal and several slices of strawberries. Be sure to save some of the plain yogurt for the next batch.

For the next batch, to be made within 5 days of the first batch, start by putting your yogurt maker somewhere where it won't be disturbed for 8 hours.

Measure the contents of your jars and then heat that amount of milk to 180 degrees, pour it directly into the clean yogurt jars, and then cool it to 110 degrees.

Now, QUICKLY remove one tablespoon of milk from each pint of milk. Add to the combined amount, for each tablespoon, 1/2 teaspoon of your starter yogurt.

Distribute the mixture evenly into the jars, stirring it in gently. Cover the jars and place in the yogurt maker where they won't be disturbed for the next 8 hours. Be SURE the temperature doesn't fall below 106 degrees.

Check it after 8 hours. If it isn't done, check it again every hour until it is.

Refrigerate immediately - add amendments when it's cold - reserve some of the batch for the next batch of yogurt.

If you do not succeed, it may be because your equipment wasn't thoroughly clean, or because you didn't heat the milk to 180 degrees - or heated it too much, or because you let the temperature fall below 106 degrees, or because the culture is too old, or because there were antibiotics in the milk.

Mostly, remember to NOT eat every last drop of your most recent batch. Keep a few teaspoons to form the starter for the next batch. Yogurt lives for 6-7 days, but it's too old to serve as a starter after 5 days.

This can be made with skim milk, whole milk, half-and-half.