The Scoville Heat Units was developed by Wilbur L. Scoville (1865-1942). The scale measures the the amount of capsaicin in peppers. Capsaicin is the chemical mix found in peppers that causes it to burn on your tongue and make you sweat. Most capsaicin comes from the seeds and the ribs of the pepper.

The larger Scoville Heat Units a pepper (or a hot sauce) is assigned, the hotter it is.