In 1912, Wilbur Scoville, a chemist for the Park-Davis pharmaceutical company, developed the first
systematic laboratory approach used to measure pungency in chiles, the "Scoville Organoleptic Test." Scoville
ground chiles and diluted them with sugar water. Scoville kept on adding sugar water to samples until testers
could no longer feel the burn. A number was then assigned to each chile pepper based on how much it needed
to be diluted before the testers could no longer taste/feel the heat.
This dilution is called the Scoville Heat Unit. (Chart at bottom of page.)
This procedure is more accurate than the taste test technique and less expensive than more advanced laboratory
techniques; although the measure of pungency is still subjective and depends on the taster’s palate and
sensitivity to the capsaicin (the chemical compound that gives chiles their heat) that are responsible for
pungency. There is also the fact that pepper plants that are stressed for water have hotter peppers than ones that
have more irrigation. Not to mention that there are only so many peppers a person can taste at a time.
Today, there is a sophisticated laboratory process called High Performance Liquid Chromotography or HPLC, measures
the amount of capsaicinoids (capsaicin) in parts per million. In this procedure, chile pods are dried, then ground;
the capsaicins are extracted, and the extract is analyzed for total heat present as well as the individual
capsaicinoids present. This method is more costly than the Scoville test or the taste test but much more accurate.
While the measurement is in ASTA pungency units, not Scoville units, the scores are often converted to
approximate Scoville unit values.
About Capsaicinoids
All hot peppers contain capsaicinoids, natural substances that produce a burning sensation in the mouth, causing
the eyes to water and the nose to run, and even cause intense perspiration. Capsaicinoids have no flavor or odor,
but act directly on the pain receptors in the mouth and throat. The primary capsaicinoid, capsaicin, is so hot that
a single drop diluted in 100,000 drops of water will produce a blistering of the tongue.
Capsaicinoids are found primarily in the pepper's placenta--the white "ribs" that run down the middle and along
the sides of a pepper. Since the seeds are in such close contact with the ribs, they are also often hot. In the rest
of the vegetable, capsaicinoids are unevenly distributed throughout the flesh, so it is likely that one part of the
same pepper may be hotter ot milder than another. You can reduce the amount of heat in a chili pepper by
removing the ribs and seeds, but you should wear gloves while doing so.
Capsaicinoid content is measured in parts per million. These parts per million are converted into Scoville heat
units, the industry standard for measuring a pepper's punch. One part per million is equivalent to 15 Scoville
units. Bell peppers have a value of zero Scoville units, whereas habaneros - the hottest peppers - register a
blistering 200,000 to 300,000 or more. Pure capsaicin has a Scoville heat unit score of 16 million.
How can you stop your mouth from burning?
There are several remedies for the effects of eating a pepper that is too hot for you, something that is usually
discovered when it is too late. (Eventually, you can build up tolerance to the heat of peppers, and will be able to
eat hotter and hotter chilis without having to resort to these cures.) Many people recommend drinking tomato
juice or eating a fresh lemon or lime, the theory being that the acid counteracts the alkalinity of the capsaicin.
Some people won't begin eating hot peppers without a pitcher of cold water handy, though this is not the best
idea. The capsaicin, which is an oil, does not mix with the water but is instead distributed to more parts of the
mouth. More useful solutions include drinking milk (rinsing the mouth with it as you sip and spitting it out) or eating rice or bread,
which absorb the capsaicin. Some people's favorite retaliation against attack by hot chili pepper is to simply eat another.
And if that doesn't work, eat another one.
The chart below rates chiles, with 0 being mildest and 10 highest heat.
- Mild: 0 to 5,000 SHUs
- Medium: 5,000 to 20,000 SHUs
- Hot: 20,000 to 70,000 SHUs
- Extreme: 70,000 to 300,000 SHUs
Ranges stated vary because the capsaicin levels of chiles grown even from the same seeds will vary:
- The capsaicin can vary considerably within a species—by a factor of 10 or more‚ depending on seed lineage,
climate, irrigation and even soil.
- The original Scoville test is an organoleptic test on humans, so even measurements of the same sample can
vary by 50%.
- When one looks at a score, one generally doesn’t know if it is an original Scoville test or a more accurate
High Pressure Liquid Chromatography test. That’s why numbers from different sources vary so widely.