Sour Cream

Sour cream is nothing but cream that bacteria have worked on. They eat the milk sugar and turn it into acid, and that acid tightens the milk proteins into a soft, thick body. That's the whole trick. No acid, no thickness — just sweet, thin cream.

Choose it with your eyes and nose before you ever taste it. Good sour cream looks velvety and holds its shape on a spoon, and smells clean and pleasantly sour, almost like yogurt with a note of butter. A little pale liquid pooling on top is nothing to fear — that's just whey. Stir it back in and the cream is as good as before. If it smells sharp, bitter or like chemicals, put it back.

Some people say the fattier it looks, the better it is. No! Fat only makes it richer, not more honest. A thin, low-fat sour cream can still be perfectly fresh and well-fermented, while a thick, fatty one can be old and starting to turn. This misconception leads cooks to judge quality by thickness alone, and they end up buying products propped up with starch instead of properly cultured — thick on the shelf, but gluey on the tongue instead of melting, and missing that clean sour bite that real fermentation gives.