What is the Scoville Heat Unit

Working as a chemist for Parke Davis, the pharmaceutical company, Wilbur Scoville set out to develop a unit of measure for the heat in chile peppers.

The test he came up with is a dilution taste test where ground chile peppers are diluted with a sugar-water solution and tasted. The level at which there is no longer a burning sensation is then determined. So, the amount of water needed to dilute the pepper determines where that pepper will fall on the scale.

The Scoville Unit

The Scoville scale is a measurement of the spicy heat from a chili pepper. The number of “SHU” Scoville Heat Units indicates how much capsicum is present. Capsicum is the chemical in the chili pepper that stimulates nerve endings in the skin, but especially the mucous membranes.

The scale was named after the original creator Wilbur Scoville in 1912 and American pharmacist. His method is known as the Scoville Organoleptic Test which uses a high performance liquid chromatography method that makes it possible to measure how much capsicum is present in a chili pepper.

The Scoville method involved using an alcohol extract of the capsicum oil from a pepper and added incrementally to a sugar water solution. A panel of judges would then drink the solution and base the Scoville heat units by how long the symptoms of capsicum was present in the mucous membranes. One could imagine how the rates could fluctuate from one person to another depending on their tolerant of capsicum.

The very least pungent of all chile peppers, and not coincidentally the most popular, is the bell pepper. With a rating of zero Scoville Units , the bell pepper provides a base level of heat, or lack thereof.

On the other end of the scale is the Habanero. Weighing in at over 300,000 Scoville units, this pepper is barely consumable by most humans. The hottest strain of the Habanero, the “Red Savina”, has been tested at some 577,000 Scoville units. Wow!

The following scale gives you an idea where all the other peppers fall in line.


The Heat Scale!

Scoville Units

0-100 Bell and Sweet Peppers
500-1000 New Mexican Peppers
1000-2500 Ancho, Pasilla and Cascabel Peppers
2500-5000 Jalapeno and Mirasol Peppers
5,000-15,000 Serrano
15,000-30,000 de Arbol Peppers
30,000-50,000 Cayenne and Tabasco Peppers
50,000-100,000 Chiltepin Peppers
100,000-350,000 Scotch Bonnet and Thai Peppers
200,000-577,000 Habanero Peppers
16 million Pure Capsaicin


Capsaicin – Where the
Heat Comes From!

The seeds themselves do not produce any capsicum, and the seeds do not  make a pepper hot. While the capsicum is present in all parts of the pepper, it is concentrated mainly in the membrane. Removing as much of the white  membrane as possible can alleviate some of the heat of the pepper.

“The active principle that causes the heat in chile peppers is a crystalline alkaloid generically called capsaicin. It is produced by glands at the junction of the placenta and the pod wall. The capsaicin spreads unevenly throughout the inside of the pod and is concentrated mostly in the placental tissue.

Capsaicin is a super strong and stable alkaloid interestingly unaffected by cold or heat, which holds its original strength despite time, cooking, or freezing. Because it has no color, flavor, or odor, the exact amount of capsaicin present in chiles can only be measured by a specialized laboratory procedure known as high performance liquid chromatography (HPLC).  Even though it has no odor or flavor, it is one of the most pungent compounds known, detectable to the palate in dilutions of one part in seventeen million. It is slightly soluble in water, but very soluble in alcohols, fats, and oils.”

Whatever the case, it is capsaicin where you will find the heat. This information and lots more was found in the article, “The Nature of Capsaicin“, by Dave DeWitt, and excerpted from his book, The Chile Pepper Encyclopedia . His book provides a wealth of information on all things chile pepper and has brought Mr. DeWitt acclaim as the Pope of Peppers