What Are Scoville Units?

by: Nick Lindauer
To understand what a Scoville Unit is, one must understand what they measure. All hot peppers contain capsaicinoids, natural substances that produce a burning sensation in the mouth, causing the eyes to water and the nose to run, and even induce perspiration. The primary capsaicinoid, capsaicin, is so hot that a single drop diluted in 100,000 drops of water will produce a blistering of the tongue.
Capsaicinoids are found primarily in the pepper’s placenta – the white “ribs” that run down the middle and along the sides of a pepper. Since the seeds are in such close contact with the ribs, they are also often hot.
Capsaicinoid content is measured in parts per million. These parts per million are converted into Scoville Heat Units (SHU), one part per million is equivalent to 15 Scoville Units. The Scoville Unit is derived from a series of tests using a solution of water and sugar. The dilutions are increased until the chile no longer burns the mouth. Take for example, Blair’s After Death Sauce which has been measured at 50,000 Scoville Units. To dilute the heat in one bottle of Blair’s After Death, you would need over 3,000 units of water to dilute the heat to the point where the average human tongue could no longer feel it.
The hotter the chile of the sauce, the greater the amount of water required to dilute it becomes. The Scoville Organoleptic Test is still used, however it has mostly been replaced by a process called high performance liquid chromatography. This process converts measurements of capsaicin from the standard parts per million to the more popular Scoville Units.
Surprisingly, the bell pepper is used as a baseline for the Scoville Unit rating. The bell pepper essentially has a rating of zero Scoville Units, thus it acts as the lowest level of heat on the Scoville scale.
On the other end of the scale is the Habanero pepper. At over 300,000 Scoville Units, the Habanero certainly sets the limit as the hottest pepper. The “Red Savina,” the hottest strain of the Habanero, has been measured as around 577,000 Scoville Units. Pure capsaicin stacks up at 16 million Scoville Units!!!
Who is Wilbur Scoville?
A brief timeline of the man behind the heat scale
To chileheads and hot sauce lovers, he is the man behind the heat scale. Wilbur Scoville was born in 1865. In 1912 while working for the Parke Davis pharmaceutical company he developed the Scoville Organoleptic Test. In 1922, Scoville won the Ebert prize from the American Pharmaceutical Association and in 1929 he received the Remington Honor Medal. Scoville also received an honorary Doctor of Science from Columbia University.
Scoville wrote The Art of Compounding which was first published in 1895 and has gone through at least 8 editions. The book was used as a pharmacological reference until the 1960’s. Scoville also wrote Extract & Perfumes which contained hundreds of formulations -- after all Scoville had a knack for compounding. Scoville died in 1942 but his name will forever go on with the Scoville Heat Unit and in the lives of chili lovers everywhere.