I don't buy sour cream all the time but it is something that we enjoy fairly often. I didn't know of any way to buy it however except in plastic containers with a plastic seal. So I tried making some instead.
I figured if I was now buying raw milk with cream that I could somehow turn some of that cream into sour cream. So I started searching that online to see what I could learn.Gemma's Bigger Bolder Baking and at OhLardy. I decided to try it two different ways. In one jar of cream I put 1/4 cup of sour cream that I had on hand and stirred it up well. In the other I put 2 teaspoons or white vinegar. I stirred them and covered them with a cloth napkin and set it on the windowsill for 24 hours. I then checked it but it didn't seem like it had done much so I left it another 24 hours.
The cream did get nice and thick. It got a little sour but not as much as I would like. I don't feel like we were completely successful yet. But it does work okay.
This time I used older cream and I think there was a little after taste from that. Next time I want to use cream that is pretty fresh. I also may try using citric acid to help sour it.