Scoville Scale

The Scoville scale is a measure of the hotness of a chilli pepper. These fruits of the Capsicum genus contain capsaicin, a chemical compound which stimulates thermoreceptor nerve endings in the tongue, and the number of Scoville heat units (SHU) indicates the amount of capsaicin present. Many hot sauces use their Scoville rating in advertising as a selling point.

It is named after Wilbur Scoville, who developed the Scoville Organoleptic Test in 19121. As originally devised, a solution of the pepper extract is diluted in sugar water until the 'heat' is no longer detectable to a panel of (usually five) tasters; the degree of dilution gives its measure on the Scoville scale. Thus a sweet pepper, containing no capsaicin at all, has a Scoville rating of zero, meaning no heat detectable even undiluted. Conversely, the hottest chiles, such as habaneros, have a rating of 300,000 or more, indicating that their extract has to be diluted 300,000-fold before the capsaicin present is undetectable. 15 Scoville units is equivalent to one part capsaicin per million. Thus the highest concentration of pure 100% capsaicin corresponds to 15,000,000 Scoville units. The greatest weakness of the Scoville Organoleptic Test is its imprecision, because it relies on human subjectivity.

Later analytical developments such as high performance liquid chromatography (HPLC) (also known as the "Gillett Method") have now enabled the Scoville rating to be determined by direct measurement of capsaicin rather than sensory methods.

Scoville ratings may vary considerably within a species—easily by a factor of 10 or more—depending on seed lineage, climate and even soil. This is especially true of habaneros. In addition the measurement process itself is imprecise: a food industry source says that "the coefficient of error is 50% for the Scoville method and less than 12% for the HPLC method"2

15,000,000-16,000,000
(Sources vary) Pure capsaicin3456
dihydrocapsaicin6
Blair Lazar's "16 Million Reserve" product, said to be pure capsaicin78
9,100,000 Nordihydrocapsaicin6
8,600,000 Homodihydrocapsaicin and homocapsaicin6
7,100,000 "The Source" hot sauce
5,300,000 Police grade Pepper spray
2,000,000 Common pepper spray or Pepper Bomb
350,000 - 580,000 Red Savina habanero
100,000 - 350,000 Habanero chile
100,000 - 325,000 Scotch bonnet
100,000 - 225,000 African birdseye (aka "African Devil", "Piri-Piri")
100,000 - 200,000 Jamaican hot pepper
100,000 - 125,000 Carolina cayenne pepper
95,000 - 110,000 Bahamian pepper
85,000 - 115,000 Tabiche pepper
50,000 - 100,000 Chiltepin pepper
50,000 - 100,000 Rocoto
40,000 - 58,000 Pequin pepper
40,000 - 50,000 Super chile pepper
40,000 - 50,000 Santaka pepper
30,000 - 50,000 Cayenne pepper
30,000 - 50,000 Tabasco pepper
15,000 - 30,000 de Arbol pepper
12,000 - 30,000 Manzano pepper, Ají
5,000 - 23,000 Serrano pepper
5,000 - 10,000 Hot wax pepper
5,000 - 10,000 Chipotle
2,500 - 8,000 Jalapeño
2,500 - 8,000 Santaka pepper
2,500 - 5,000 Guajilla pepper
2,500 Tabasco Sauce
1,500 - 2,500 Rocotilla pepper
1,000 - 2,000 Pasilla pepper
1,000 - 2,000 Ancho pepper
1,000 - 2,000 Poblano pepper
700 - 1,000 Coronado pepper
500 - 2,500 Anaheim pepper
500 - 1,000 New Mexico pepper
500 - 700 Santa Fe Grande pepper
100 - 500 Pepperoncini pepper
100 - 500 Pimento
0 Bell pepper

Disputed, unverified or erroneous claims of SHU values:

855,000 Naga Jolokia pepper