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 I knew wasabi was different--from the time I thought a bowl of it was guacamole and ate a bunch at once. It's a different experience of spiciness; you feel it in your sinuses, and it passes quickly.
Come to think of it, I've had an accidental experience with Szechuan petters, too, eating Chinese food on a date in the dark at a drive-in movie. They were just in there to contribute flavor, not really to be directly eaten. That stuff just keeps burning, waaaay longer than chili peppers.