For a while, I was under the impression that all spiciness, or burning sensation in food flavoring, would come from capsaicin, the compound that causes it in chili peppers. Then I realized that Sichuan peppers are a quite different kind of heat. Wasabi (horseradish) is different yet again.
How many hot-flavored compounds are there? At least five!
Kalsec: "The Elements of Heat"
@clacke Indeed, Sichuan peppers activate nerve endings in the lips and gums, which you can test by eating Sichuan food soon after having gum surgery, though you would be very much better off just taking my word for it instead.