Okay, so white chocolate is chocolate made without the cocoa solids. Because of the lack of cocoa powder, it’s not considered chocolate as-such by the FDA (and other such organizations). Because of this in turn, it can be made with other materials in place of (the relatively healthful) cocoa butter — like, say, hydrogenated vegetable oil — and still be labeled “white chocolate”.

This deal with cocoa butter is also a major differentiation between chocolate and fudge. Fudge is actually kind of a variant of caramel (the candy, not the burned sugar). To make caramel, you boil milk and sugar together — otherwise also important ingredients in milk chocolate — to what is known in confectionary circles as the “soft ball” stage. To make fudge, you then beat the mixture while it cools. So fudge is basically beaten caramel that tends to (though need not) be flavored with cocoa powder. In contrast, to call something “chocolate”, it needs to be based entirely on chocolate products — mainly, cocoa powder and cocoa butter.* Considering that fudge need not contain any chocolate product, this does not describe fudge. Actually they’re pretty far apart, as far as confections go.

While we’re here, the difference between toffee and taffy basically comes down to one minor detail of production; they tend to be made from the same recipe (basically a caramel one, with butter), and by the same process. The only thing is, taffy is pulled as it cools, aerating it and making it chewy. Salt water taffy was invented (or at least popularized) in Atlantic City. I guess that explains why it’s so much more common on the east coast than over here. And why it’s all over the place when you go to the Jersey boardwalks. It doesn’t really contain salt water. Or even any more salt than other candy contains.

*: Chocolate liquor is the natural result of grinding cocoa beans to a smooth state; it consists of what would otherwise be extracted separately as powder and butter.