Homemade sour cream requires just two ingredients: heavy cream and an acid, like freshly squeezed lemon juice or distilled white vinegar. I like to use a ratio of 1 cup cream to 1 tablespoon lemon juice or vinegar . More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.