Homemade yogurt is not going to come out like commercial yogurt, because you aren't going to have all of the additives they use in the store-bought type, but you can make a delicious yogurt to be proud of using this simple recommended method.
Over the years, I have tried many different yogurt recipes, many of them advocating the use of thermometers, water baths, the addition of powdered milk, yogurt making machines and strict attention to timing and detail .
Having had varying degrees of success with them, there were also a few drastic failures. I am not saying that the various methods won't produce edible yogurt. I am saying that much of it is unnecessary.
All that is needed to produce a lovely and delicious batch of yogurt is about a tablespoonful of yogurt to use as starter for your batch, using yogurt purchased at the store or borrowed from a friend or family member, or whey left over from making soft cheese such as Paneer, (equally as easy to make as yogurt), and milk.
It is not necessary to purchase powdered yogurt starter. So how do we make successful yogurt every time?
Bring your milk to a boil – yes that's right, a boil. Let it scald, then cool down to lukewarm – about 120 degrees fahrenheit. After it is cooled to this temperature, remove the skin off the top and add your starter, stir gently, place in container, place lid on loosely, and place the yogurt where it will be undisturbed for at least 5 hours at a 100 degree temperature.
I use my oven, which has a light in it. If your oven has a pilot light, that will work too. A 40-watt bulb will produce enough heat to curdle your milk, so placing your yogurt under the glare of a lamp or bulb should also work, however, in this instance I would wrap it in a dish towel or other clean cloth to hold in the heat. Check after five hours; it should be ready, but may take a bit more time to set just right After your yogurt is set, if you find it too loose for your taste, you may strain it through a cheesecloth, which will produce a lovely Greek-type yogurt. However, straining too much fluid off the top will leave your yogurt dry and chalky. I happen to like mine like that, but try to shoot for smooth and creamy. Don't add fruit or anything to your yogurt before it is set. All additions are made at the end of the process.
Homemade Yogurt Recipe
1 T. yogurt
Bring milk to a boil, then let cool to lukewarm, approx. 120 degrees F
Add yogurt when milk cools, stir in gently and pour in container, glass preferably, that has been sterilized in boiling water for 5 mins.
Place in oven or other warm area, where it will be undisturbed for at least 5 hrs.