You need the milk to be 115˚ when you add the culture so you can either, carefully, heat it on the stove or in the crockpot: Put the milk in a 2-3 quart crock pot (I only have a 1.5q and a 6q so I used my 6q). Turn it to low for 2½ hours.
Turn the crock pot off and let it sit, with the lid on for 3 hours.
Yes, that’s it just let it sit. But set yourself a timer so you don’t forget about it.
Next, add in the yogurt or the live powdered culture whisk it in so it is well combined. (If you are sweetening it - now is the time for that as well)
Put the lid on and:
***********This is very important!!!***************
you are trying to provide a warm environment for the bacteria to cultivate so you do NOT want the milk mixture to get cold. So you are going to wrap the crock pot in a couple towels. I used two beach towels and wrapped it up snug as a bug and then I place it inside my extra oven to keep it extra insulated.
Then let it sit just like that for at least 8 hours. I typically (especially when using goat milk since it just seems to need to culture longer) leave it for about 12-16 hours.
NOW.
You CAN leave it alone at this point to chill and you will have a perfectly wonderful thick, creamy yogurt.
But I am me. I am rather picky about my beloved dairy products. So I took it one step further.
I wanted the extra thick texture of greek yogurt. So I got out my trusty cheesecloth and made a little hammock with 3 layers (don’t want to loose the yogurt - just the whey!) and put the yogurt (I had to do it in 3 batches) in it and closed it with a heavy rubber band. Then I hung it over a bowl in the fridge for about 3 hours.
Recipe by Foods of Our Lives at https://www.foodsofourlives.com/2011/03/homemade-greek-yogurt/