Crème fraîche is a fermented cream that is thick and slightly tart tasting. In France, where it originated, it is made from unpasteurized heavy cream that is allowed to ferment naturally. In countries where unpasteurized cream is unavailable, bacteria cultures are added to the cream to make crème fraîche. It is preferred by many for cooking in place of regular heavy cream because it will not break or become unstable. It can be used just like heavy cream in both hot and cold preparations.