This "sticky" answered a half-dozen questions I didn't know I had!
Here's a chart I searched, after Alton Brown's show "The Big Chili"
Scoville Heat Unit Scale
Pepper Type -- Heat rating (in Scoville heat units)
Red Amazon 75,000
Chiltecepin 70,000 - 75,000
Tabasco 30,000 - 50,000
Smoked Jalapeno (Chipotle) 10,000
Serrano 7,000 - 25,000
Jalapeno 3,500 - 4,500
Poblano 2,500 - 3,000
TAM Mild Jalapeno 1,000 - 1,500
Anaheim 1,000 - 1,400
New Mexican 1,000
Bell & Pimento 0
Here's a link:
-- and the following is cut/pasted from this link . . . (Fair use, and copyright stuff you know.)
is what puts the heat or pungency in chiles. It is a compound that is insoluble in water, tasteless and odorless. It is made of seven closely related alkaloid or capsaicinoids. Three of these components cause the “rapid bite” at the back of the palate and throat and two others cause the long, slow burn on the tongue. Capsaicin is produced and found in the placental partition (“white” cross wall and veins) of the pod. The seeds become pungent through contact with the placenta.
In 1912, Wilbur Scoville, a chemist under the employ of Parke Davis Pharmaceutical Company, developed a method to measure the heat level of chiles. The test is call the Scoville Organoleptic Test. In his original testing, Mr. Scoville blended various pure ground chiles with a sugar-water solution. A panel of testers then sipped the concoctions in increasingly diluted concentration, until they reached the point at which the solutions no longer burned the mouth. A number was then assigned to each variety of chile based on how much it needed to be diluted before heat was no longer tasted. This measurement of millions of drops of water-sugar solution is then translated into Scoville Heat Units (SHU)
in multiples of 100. This technique is subjective and depends on the taster’s palate and it’s response to the pungent chemicals. The accuracy of this test is often criticized and modified versions have been developed.
The most accurate method for measuring pungency in chiles is a High performance liquid chromatography. 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 device for analysis. This method is more costly than the Scoville test or the Taste test but much more accurate. This method measures the total heat present as well as the individual capsaicinoids present.