Sour Cream

Sour cream is the North American counterpart to crème fraîche, however, it is lower in fat and it has a more distinctive tartness. Because it is made by adding lactic acid to a mixture of cream and milk, it is not as stable as crème fraîche when heated. In a pinch, it can be used to replace crème fraîche, but it should be added at the end of cooking and served immediately, otherwise the sauce has a tendency to develop a grainy appearance.