The Scoville scale is a measurement of the pungency (spiciness or "heat") of chili peppers, as recorded in Scoville Heat Units (SHU), based on the concentration of capsaicinoids, among which capsaicin is the predominant component. The scale is named after its creator, American pharmacist Wilbur Scoville, whose 1912 method is known as the Scoville organoleptic test. The Scoville organoleptic test is the most practical method for estimating SHU and is a subjective assessment derived from the capsaicinoid sensitivity by people experienced with eating hot chilis.
An alternative method, using high-performance liquid chromatography (HPLC), can be used to analytically quantify the capsaicinoid content as an indicator of pungency. As of 2011, the subjective organoleptic test has been largely superseded by analytical methods such as HPLC.
In the Scoville organoleptic test, an exact weight of dried pepper is dissolved in alcohol to extract the heat components (capsaicinoids), then diluted in a solution of sugar water. Decreasing concentrations of the extracted capsaicinoids are given to a panel of five trained tasters, until a majority (at least three) can no longer detect the heat in a dilution. The heat level is based on this dilution, rated in multiples of 100 SHU.