Measuring the Heat of Hot Peppers

Chili pepper heat is measured in Scoville Units. Developed by Wilbur Scoville in 1912, Scoville Units measure chili pepper heat in multiples of 100, with the bell peppers at 0 and the habañero at over 300,000 Scoville Units.
Way back in 1912, a hothead named Wilbur Scoville came up with a way to measure the heat of chile peppers in the most straightforward way imagineable: he ground up chiles, diluted different quantities of the powder in sugar water, fed the dilutions to people and tested their reactions.

Capsaicins, which give hot peppers their hotness, are so potent in pure form that old Scoville had to break out the zeros: One part capsaicin per million rates 15 Scoville units. Once he had that starting point, Scoville wrote up a 1-10 scale of capsaicin concentrations, in multiples of one hundred, starting at 0 and topping off at a blistering 350,000. That's 35 percent capsaicin and 65 percent sugar water.

The Scoville Scale	__Pepper
16,000,000	__Pure capsaicin
350,000 - 577,000	__Red Savina™ Habanero*stop the press!
100,000 - 350,000	__Thai, Scotch Bonnet
50,000 - 100,000	__Chiletepin, Pepin
30,000 - 50,000	__Tabasco, Cayenne
15,000 - 30,000	__Chile de Arbol
5,000 - 15,000	__Serrano
2,500 - 5,000	__Jalapeno, Mirasol
2,000 - 2,500	__Cascabel, Cherry
1,500 - 2,000	__Ancho, Pasilla
1,000 - 1,500	__Espanola
500 - 1,000	__Anaheim, New Mexican
0 - 100	__Bell, Sweet, Pimento, Pepperoncini
Scientists in India say they have identified the world's hottest chilli - 50% more fiery that its Mexican rival. Experts at a defense research facility in the north-eastern state of Assam say the Naga Jolakia chilli measured at 855,000 Scoville units.

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.

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