Yogurt making is something I got into during the dirt poor graduate school days. A friend had mentioned a few years before that she made her own, but I did not try it until my beloved commercial yogurt seemed too expensive to buy on our limited budget. (We eat A LOT of yogurt.) Yogurt is one of those things that is fairly simple to make, but people are really impressed when you whip out your homemade yogurt! It's also very good in place of sour cream, and good in casseroles.
Here's the recipe I use. There are several variation on the web and in other cookbooks, so if this one does not work for you, there are others you can try. Homemade yogurt is not as thick as commercial yogurt, but it's even more delicious!
Yogurt (makes 2 qts)Combine in a large bowl:3 c. milk powder
3 c. warm water
Stir well. Add:1 can of evaporated milk OR 1 2/3 c scaled whole milk. (I just use skim, and it works. Your yogurt will be thicker the higher fat content of your milk, so mine is thinner than some homemade yogurts.)
Combine separately:1/4-1/2 cup plain yogurt (use yogurt with active cultures- it will say on the carton. After the first one you buy, you can use the homemade as starter if you eat it fairly regularly.)
1 c. milk from the bowl.
Blend until smooth and return to remaining milk. Mix well. Pour into clean
glass jars and incubate at 110-120 degrees F until set. Refrigerate.
To incubate: Some people have yogurt makers, but they cost 30-50 dollars apiece, so this may or may not be a cost savings to you. I've been unsuccessfully watching for a yogurt maker at yard sales. Many people use their oven with just the oven light on. I have never had an oven with a light, so I use a cooler filled with hot water. I use a candy thermometer to check the temperature every hour or so, and add a little more hot water as I go along. To get the thickness I want, I usually leave it in 5-8 hours. It works out fine! We mix in jelly, jams, fruit, granola, or sugar to eat as yogurt, and use it to replace sour cream in other recipes.
My latest batch, incubating in the cooler. I close the lid and put a blanket over it, and have not lost a batch yet!