Education
What is Scoville?
The Scoville scale is a measurement of the pungency (spiciness or "heat") of chili peppers and other spicy foods, recorded in Scoville Heat Units (SHU).
The History
In 1912, American pharmacist Wilbur Scoville developed a method for measuring the "heat" of various chili peppers. Originally called the Scoville Organoleptic Test, it involved diluting an extract of the pepper in sugar water until the "heat" was no longer detectable by a panel of human tasters.
The degree of dilution gave the pepper its SHU rating. For example, a pepper with 2,500 SHU required 2,500 parts sugar water to one part pepper extract to neutralize the heat.
How it's measured today
While the original test relied on human taste buds (which can be subjective and prone to "palate fatigue"), modern testing uses High-Performance Liquid Chromatography (HPLC).
HPLC measures the actual concentration of capsaicinoids in a pepper. These results are then converted back into Scoville Heat Units to maintain the familiar scale we use today.
What is Capsaicin?
Capsaicin is the active component of chili peppers that produces the burning sensation. It's an irritant for mammals, including humans, and produces a sensation of burning in any tissue with which it comes into contact.
Interestingly, birds are immune to capsaicin, allowing them to eat peppers and spread the seeds without the burning sensation!
Reference Benchmarks
To give you an idea of where common items sit on the scale: