The Scoville scale is a measurement in heat units created by American pharmacist Wilbur Scoville in 1912. Basically, it’s a numerical rating to determine how hot each pepper is. The actual number of Scoville heat units indicates the amount of Capsaicin in each pepper. Capsaicin is the natural chemical found in hot peppers that hits the mucous membranes and fills your mouth with love. HA! The habanero is the hottest natural pepper.