What is a Scoville Heat Unit?

Scoville Heat Units are used to specify of the hotness of food, specifically chili peppers. In 1912, Wilbur Scoville devised a system to determine how hot foods are, using a panel of tasters to provide heat scores for different peppers. Although Wilbur’s name is still used for the scale, the current method is much more scientific.

The sensation of heat that is experienced from eating certain peppers is attributable to a chemical called capsaicin. The more capsaicin present in a pepper, the hotter it will seem. Although the Scoville scale spans from 0 to 16 million, the American Spice Traders Association (ASTA) set the standard for conversion from ppm (parts per million) of capsaicin to Scoville Heat Units as 1:15. This means that a sweet bell pepper has a score of 0 because there is no capsaicin present, and pure capsaicin crystals have 15 to 16 million units.

 As is evident from the table below, Scoville scores vary widely from one species to the next. The hottest pepper ever grown is the Naga Jolokia from Assam, India, which has a Scoville score of 855,000. There are also variations of heat from one pepper to the next within the same species; growing conditions, soil, and other factors have an affect on the amount of capsaicin within a given pepper. The numbers listed below represent the average minimum amount detectable within the item in question, but people should keep in mind that the amount of capsaicin in any single type of pepper can vary greatly.