The Scoville heat index scale is a scale used to measure the spiciness and heat of chili peppers. It measures the spicy hotness with Scoville heat units, abbreviated to SHU. It ranges from O SHU, which is where bell peppers fall, all the way up to 16,000,000 SHU which is basically pure capsaicin. Capsaicin is the active constituent in chilies which makes them hot. The Scoville heat index scale is named for Wilbur Scoville who devised the method in 1912. It is a method that uses alcohol extracts of the capsaicin oils. The capsaicin extract is added in small increments to a sugar-water solution until it is just barely detectable at all to the panel of tasters. This dilution is what is ultimately measured and what determines the chili’s place on the scale. There has been controversy over this method since the argument can be made that everyone’s tastes are different. Due to this there are also more refined and less objective methods as well such as high performance liquid chromatography.