There is a reason an objective rating scale for heat in chiles had to be invented. Consider this scenario: Two people are eating the same dish with the same amount of hot chiles. One is soon on the floor clutching her throat; the other is happily chowing down, staying infuriatingly cool.
Was that chile hot? Depends upon whom you ask.
Chile heat is measured in Scoville Heat Units, a method to determine just how hot, or pungent, any chile is. According to “The Chile Pepper Encyclopedia,” by David DeWitt, in 1912 Wilbur L. Scoville was a pharmacologist with a Detroit company, Parke Davis, which was using capsaicin in its muscle salve. Scoville, in the course of his work, developed the Scoville Organoleptic Test.
“This test used a panel of five human heat samplers tasted and analyzed a solution made from exact weights of chile peppers dissolved in alcohol, then diluted with sugar water. The hotter the sample. the greater the amount of water required to dilute it, until the pungency was no longer detectable to the palate” according to DeWitt’s encyclopedia.
“So, if the dilution required was 1,000 units of water to 1 unit of the alcohol sample, the sample was said to have a pungency of 1,000 Scoville Units.”
Later, in1980, high performance liquid chromatography was developed to determine more accurately the pungency, which also was expressed in Scoville Units. Scoville Heat Units remain the standard industry measurement, says DeWitt.
The pungency of chiles is caused by a group of alkaloids called capsaicinoids. There are 15 different capsaicinoids that make up capsaicin, according to The Chile Pepper Institute at the New Mexico State University. So, there are endless possibilities for flavor and heat combinations.
So how hot is hot? The habanero, which we all know is hot, registers between 100,000 and 500,000 Scoville Units. But then consider the bhut jolokia, also known as the ghost pepper. It comes from India and measures at 1,001,304 Scoville Heat Units. Ow!
A serrano chile is 5,000-15,000, while a long green chile, let’s say a hot Hatch chile, is between 500-1,000 Scoville Units. The pickled pepperoncini you put on your pizza is between 10-100, and the mild bell pepper ranks right down at zero.
Yet, I have heard people ask a cook or server to not put any bell peppers in their food because they “can’t take spicy food.” I usually suspect they just don’t like bell peppers.
Information for this article came from the New Mexico State University and “The Chile Pepper Encyclopedia.” For more on chiles, go to chilepepperinstitute.org.
An earlier version of this article mentioned that the Chile Pepper Institute was at the University of New Mexico. The institute is at the New Mexico State University. The error has been corrected.