Is it possible to make Sour Cream at home?
Sour cream is just cultured cream. You want to take fresh cream and then add the correct culture, then let it sit.

One way is to add a small amount of cultured buttermilk (with live cultures) to the cream. Put the mixture in a clean container and leave it in a warm place. In a day or two the cultures will have turned the cream "sour." and it's ready to use. At this point, you can use your fresh sour cream to start other sour creams as well.