What is a Scoville, or Scoville unit?

A lot of folks have asked me about the word scoville.  How did I come up with it?  What does it mean?

Basically it is the measurement of heat in a chili pepper.  

The following is from Wikipedia and describes it very well.

Also a Scoville chart at the end of the page

The Scoville scale is the measurement of the pungency (spicy heat) of chili peppers.

The number of Scoville heat units (SHU)^[1] indicates the amount of capsaicin present per unit of dry mass. Capsaicin is a chemical compoundthat stimulates chemoreceptor nerve endings in the skin, especially the mucous membranes.

The scale is named after its creator, American pharmacist Wilbur Scoville. His method, devised in 1912, is known as the Scoville Organoleptic Test.^[2] A modern method to directly measure capsaicinoid content in peppers is high-performance liquid chromatography.

In Scoville's method, a measured amount of alcohol extract of the capsaicin oil of the dried pepper is produced, after which a solution of sugar and water is added incrementally until the "heat" is just barely detectable by a panel of (usually five) tasters; the degree of dilution gives its measure on the Scoville scale. Thus, a sweet pepper or a bell pepper, containing no capsaicin at all, has a Scoville rating of zero, meaning no heat detectable.^[3] The hottest chilis, such as habaneros and nagas, have a rating of 200,000 or more, indicating their extract must be diluted over 200,000 times before the capsaicin presence is undetectable.^{[citation needed]} The greatest weakness of the Scoville Organoleptic Test is its imprecision, because it relies on human subjectivity. Tasters are given only one sample per session. Results vary widely, up to 50%, between laboratories.^[4]

Spice heat is usually measured by a method that uses high performance liquid chromatography (HPLC). This identifies and measures the concentration of heat-producing chemicals. The measurements are used in a mathematical formula that weighs them according to their relative capacity to produce a sensation of heat. This method yields results, not in Scoville units, but in American Spice Trade Association (ASTA) pungency units. A measurement of one part capsaicin per million corresponds to about 15 Scoville units, and the published method says that ASTA pungency units can be multiplied by 15 and reported as Scoville units. Scoville units are a measure for capsaicin content per unit of dry mass.^[6][7][8] This conversion is approximate, and spice experts Donna R. Tainter and Anthony T. Grenis say that there is consensus that it gives results about 20–40% lower than the actual Scoville method would have given.

Scoville heat units	Examples
1,500,000–2,000,000	Trinidad Moruga Scorpion[9]
855,000–1,463,700	Naga Viper pepper,[10] Infinity Chilli,[11] Bhut Jolokia chili pepper,[12][13] Trinidad Scorpion Butch T pepper,[14] Bedfordshire Super Naga,[15] 7-Pot Chili
350,000–580,000	Red Savina habanero[16]
100,000–350,000	Habanero chili,[17] Scotch bonnet pepper,[17] Datil pepper, Rocoto, Piri Piri Ndungu, Madame Jeanette, Peruvian White Habanero,[18] Jamaican hot pepper,[19] Guyana Wiri Wiri, Fatalii [20]
50,000–100,000	Byadgi chilli, Bird's eye chili (aka. Thai Chili Pepper),[21] Malagueta pepper,[21] Chiltepin pepper, Piri piri (African bird's eye), Pequin pepper,[21]Siling Labuyo (native chili cultivar from the Philippines)
30,000–50,000	Guntur chilli, Cayenne pepper, Ají pepper,[17] Tabasco pepper, Cumari pepper (Capsicum Chinese)
10,000–23,000	Serrano pepper, Peter pepper, Aleppo pepper
3,500–8,000	Espelette pepper, Jalapeño pepper, Chipotle,[17][22] Guajillo pepper, New Mexican peppers,[23] Hungarian wax pepper, Tabasco sauce
1,000–2,500	Anaheim pepper (cultivar of New Mexican peppers),[23] Poblano pepper, Rocotillo pepper, Peppadew, Sriracha sauce
100–900	Pimento, Peperoncini, Banana pepper, Cubanelle
No significant heat	Bell pepper, Aji dulce