Did you know there are actually a few types of hotness when it comes to the food we consume? The familiar heat of chile peppers comes from a compound called capsaicin, and is measured with the Scoville Heat Unit where red bell peppers rank 0 but ghost chiles are up there at 1,000,000 (jalapeños are only 2,500-8,000 SHUs). Piperine gives peppercorns that peppery hotness. And if you've ever accidentally put too much wasabi on your sushi, that's allyl isothiocyanate doing the heavy lifting.