We find that we have leftover milk now that both boys have moved out and are on their own. Years ago as a worker at a Summer Camp I learned to make yoghurt by the gallon with an electric blanket! All I had was fresh cows milk, an electric blanket, glass gallon jars, and culture from the previous days yoghurt. I do not need a gallon...just need to use up the milk before it goes bad. There are lots of instructions on the net on how to make yoghurt. So I won't bore you with details on how to make it. But I thought you might like to see what we do with it after we add the culture. For small batches we use a thermos! Its the right size for our family. Wrapped in a towel and stored in a warm place ( in the cup board above the heat vent). Its the perfect incubator for yoghurt. I do not drain the whey so our yoghurt is a medium consistancy. ( not greek or thick) Whey is very good for you.
For slightly bigger batches I use a small crockpot. Warm up the pot first. Unplug it, add the warm milk and the culture. Wrap the crock up and put in a warm place for about 10 hours. I noticed that most articles on how to make yoghurt talk about how tart it taste ( and what to add to it ect). Ours always turns out sweet ( not like super sweet as if sugar were added , just a nice flavor, not tangy)