Why is green chile hot? Well, green chile derives its heat from the amount of capsaicin present in a given pod. Capsaicin is a chemical compound that is insoluble in water, tasteless and odorless and produces a sensation of burning in tissue with which it comes into contact. It is found in chile peppers along the placenta.
Chile pepper heat is measured in Scoville Units. The number of Scoville Units, or Scoville Heat Units (SHU’s) indicates the amount of capsaicin present.
The test that measures heat is named after its creator, American pharmacist Wilbur Scoville. His method, devised in 1912, is known as the Scoville Organoleptic Test.
In Scoville’s method, a measured amount of the capsaicin oil is added to a solution of sugar and water 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. The hottest chilis, such as Habaneros, Bhut Jalokia, and Trinidad Scorpion, have a rating of 200,000 up to 2,000,000 or more, meaning their extract must be diluted over 200,000 times before the capsaicin presence is undetectable.
New Mexico green chiles have a scoville range from 350-30,000 depending upon the variety. Pure Capsaicin has an SHU rating of 15-16 million while currently the world’s hottest pepper, the Carolina Reaper, has an SHU rating of 2,200,000 with the second hottest, the Trinidad Moruga Scorpion, close behind at an SHU rating of 2,009,231. Now those are hot peppers!