What is the difference between sour cream and crème fraîche?

Both sour cream and crème fraîche are fermented milk products, made from cream. The cream is fermented with bacterial cultures which produce lactic acid, causing the cream to sour and thicken, giving a smooth viscous product.

Crème fraîche usually has a higher fat content and is not quite as soured as sour cream and tends to have a richer, less tangy flavour. Thickening agents such as gelatine or guar gum are sometimes added to sour cream, particularly to reduced-fat or ‘light’ varieties but are less often added to crème fraîche. Both are often used in dips or as an ingredient in soups or sauces.