I've made yogurt before, and top of the fridge covered with a towel is usually warm enough. Made it from nonfat dry milk, which on it's own makes more of a slimy product- but it's yogurt!
My dad used top make it from fresh water-buffalo milk.
Crème fraiche is real easy to make and should be in any kitchen. Very versatile. I make it with whole cream and buttermilk.
I found creme fresh to be very hard. Not so much to do but the "real thing" has to be made with cream that has not been pasteurized. Real hard to find for me. I have gotten it a couple of times from people I know.
The idea is to get whole un-pasturized milk then let the real thick cream settle to the top. Then skim it off and let it sit out at about 100 degrees for twenty four hours. It will get thick.
euge if you used cream and then cultured it with butter milk. That is just sour cream.
Now, butter milk is another story, most butter milk in this country is actually kefir. Real butter milk is the whey left over from churning butter.
Im a real nit picker aint I?
Funny you mention the fridge, I used to make it on the back of an old frige where the heat exchanger grill was. Made a shelf for the to yogurt to sit on the condenser. Worked great.
Maybe we need a new thread?