Wilbur Scoville & Pepper Chemistry


...It was in 1912


...whilst working for the Parke Davis pharmaceutical company that one of their chemists, Wilbur Scoville, developed a method to measure the heat level of a chile pepper. This test is named after him, it's called the Scoville Organoleptic Test, and it's a dilution-taste procedure. In the original test, Scoville blended pure ground chiles with a sugar-water solution and a panel of testers then sipped the concoctions, in increasingly diluted concentrations, until they reached the point at which the liquid no longer burned the mouth. A number was then assigned to each chile based on how much it needed to be diluted before you could taste no heat.


The validity and accuracy of the Scoville Organoleptic test have been widely criticised. The American Spice Trade Association and the International Organisation for Standardisation have adopted a modified version. The American Society for Testing and Materials is considering other organoleptic tests (the Gillett method) and a number of other chemical tests to assay for capsaicinoids involved in pungency. Even so, the values obtained by these various tests are often related back to Scoville Units. Nowadays the High-Performance Liquid Chromatography (HPLC) test is used. In this procedure, chile pods are dried, then ground. Next, the chemicals responsible for the pungency are extracted, and the extract is injected into the HPLC for analysis. This method is more costly than the previous, but it allows an objective heat analysis. Not only does this method measure the total heat present, but it also allows the amounts of the individual capsaicinoids to be determined. In addition, many samples may be analyzed within a short period.


The pungency of chile peppers is measured in multiples of 100 units, from the bell pepper at zero Scoville units to the incendiary Habanero at 300,000 Scoville units! One part of chile "heat" per 1,000,000 drops of water rates as only 1.5 Scoville Units. The substance that makes a chile so hot (and therefore so enjoyable to Chile-Heads !), is Capsaicin, and pure Capsaicin rates over 15,000,000 Scoville Units !

As the B.B.C. reported: "Scientists in India say they have identified the world's hottest chilli - nearly 50% more fiery that its nearest Mexican rival. Experts at a defense research facility in the north-eastern state of Assam say the Naga Jolakia chilli measured a breathtaking 855 thousand Scoville units as compared to the Mexican Red Savina Habanero's 577thousand Scoville units...Laboratory tests have confirmed that Naga Jolokia, a speciality from the north-east, is now the worlds hottest chilli," the laboratory's deputy director SC Das told the French news agency. The Naga Jolokia grows to about five centimetres (two inches) long and to a thickness of one centimetre (0.4 inch)."


Capsaicin levels


0-100 Scoville Units includes most Bell & Sweet pepper varieties.
500-1000 Scoville Units includes New Mexican peppers.
1,000-1,500 Scoville Units includes Espanola peppers.
1,000-2,000 Scoville Units includes Ancho & Pasilla peppers.
1,000-2,500 Scoville Units includes Cascabel & Cherry peppers.
2,500-5,000 Scoville Units includes Jalapeno & Mirasol peppers.
5,000-15,000 Scoville Units includes Serrano peppers.
15,000-30,000 Scoville Units includes de Arbol peppers.
30,000-50,000 Scoville Units includes Cayenne & Tabasco peppers.
50,000-100,000 Scoville Units includes Chiltepin peppers
100,000-350,000 Scoville Units includes Scotch Bonnet & Thai peppers.
200,000 to 300,000 Scoville Units includes Habanero peppers.
16,000,000+ Scoville Units is Pure Capsaicin


Capsaicin types


Capsaicin, also known as N-Vanillyl-8-methyl-6-(E)-noneamide, is the most pungent of the group of compounds called Capsaicinoids that can be isolated from chile peppers. It is sparingly soluble in water, but very soluble in fats, oils and alcohol. The minor Capsaicinoids include Nordihydrocapsaicin [Dihydrocapsaicin with a (CH2)5 instead of (CH2)6], Homocapsaicin [Capsaicin with a (CH2)5 instead of (CH2)4, and Homodihydrocapsaicin [Dihydrocapsaicin with a (CH2)7 instead of (CH2)6]. 

Here, causing some of the "pain", is the chemical composition of the better known of the Capsaicinoids:


(courtesy of John Henninge M.Sc. and exclusive to this website!)


16,000,000 Scoville Units


16,000,000 Scoville Units


9,100,000 Scoville Units


8,600,000 Scoville Units


8,600,000 Scoville Units


Capsaicin and Dihydrocapsaicin together make up 80-90% of the Capsaicinoids found in peppers. In the Capsicum annum species, the total Capsaicinoid content ranges from 0.1 to 1.0%, and the Capsaicin to Dihydrocapsaicin ratio is about 1:1. In Capsicum frutescens the total content ranges from 0.4-1.0% with the ratio around 2:1.