How rude the awakening, spoon poised over white W chocolate mousse, when the diner realizes that white chocolate is a figment of the imagination. There isn't such a thing.

At least not according to the Food and Drug Administration. Emil Corwin, of the FDA's Bureau of Foods, said that as defined under the Federal Food, Drug and Cosmetic Act, the term "white chocolate" is considered misbranding. According to the act, the product is "not chocolate."

And the white chocolate made in the United States often doesn't have anything at all to do with chocolate. It is usually a combination of "milk and sugar and fat," says Barry Zoumas, vice president of science and technology at Hershey Foods Corp.

Unlike European white chocolate, which at least contains cocoa butter, much of the American variety is made with cheaper fat. Manufacturers might use hardened soybean oil or some other substitute that leaves a "waxy taste in your mouth," says Zoumas. And any chocolate addict knows that much of chocolate's appeal is its texture.

"Cocoa butter is a unique fat," says Zoumas. It "melts slightly below body temperature, at 95 degrees, and it melts very quickly, so you don't get any waxy feeling." Other fats, says Zoumas, melt over a much wider range of temperatures. "They may begin melting at 91 degrees" and not finish until well over 100 degrees. "If you use a fat that melts at body temperature and above," says Zoumas, it lingers in your mouth. This makes the chocolate "taste very artificial."