What is The Scoville Scale?

What is The Scoville Scale?

Peppers contain various capsaicin amounts, which rank them all over the Scoville ScaleThe Scoville Scale is used to measure the pungency or hotness of a chile pepper. The chemical compound found in chile peppers (from the genus capsicum) that gives this piquant heat is called capsaicin (the molecular formula is (CH3)2CHCH=CH(CH2)4 CONHCH2C6H3-4-(OH)-3-(OCH3) or simply C18H27NO3), and stimulates chemoreceptor nerve endings, especially in the mucous membranes. The number of Scoville Heat Units (SHU) in a pepper or hot sauce indicates the amount of capsaicin present.

Wilbur Scoville and the Scoville Organoleptic Test

While working for the Parke Davis Pharmaceutical Company in 1912, American chemist Wilbur Scoville devised a test for rating the pungency of chile peppers. His method is known as the Scoville Organoleptic Test.

In the Scoville Organoleptic Test, a pepper extract solution is diluted in sugar syrup until the extract's "heat" is no longer detectable to a panel of (usually five) tasters. The degree of dilution determines where the pepper rates on the Scoville Scale. A sweet or bell pepper would have a Scoville rating of zero, since it contains no more than trace amounts of capsaicin and there is no heat detectable, even when it is undiluted. At the other end of the Scoville Scale, bhut jolokias (the current hottest chile peppers in the world) have a rating of approximately 1,000,000, indicating that their extract has to be diluted one million-fold before the capsaicin present is undetectable. Since it relies on human subjectivity, the Scoville Organoleptic Test can and has been shown to be inaccurate.

Wilbur Scoville tried many different methods and variations other than the one above to measure the pungency of chiles, but he found that the readings were not consistent and precise. He attempted to mix the chile pepper extract with different chemicals but was not successful at finding a more accurate solution. For decades the Scoville Organoleptic Test was the accepted way of measuring the amount of capsaicin in peppers.

High-Performance Liquid Chromatography (The Gillett Method)

Since the 1970s, chile pepper heat is now measured by what is called the Gillett Method (named after the chemist who applied it) which uses High Performance Liquid Chromatography (HPLC). This is a newer and more accurate method of quantitative analysis, and directly measures capsaicinoids and attempts to relate the measured concentration in parts per million (ppm) to the Scoville scale using a mathematical conversion factor of 15, 20 or 30 depending on the capsaicinoid.

This method yields results in ASTA pungency units. A measurement of one part capsaicin per million corresponds to about 15 Scoville Heat Units, and the published method says that ASTA pungency units can be multiplied by 15 and reported as Scoville Heat Units. 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 original Scoville Organoleptic Test would have given.

Chart of the Scoville Scale

I've complied the largest Scoville Scale Chart on the internet of the hottest chile peppers and selected hot sauces. This has been assembled from sources and charts all over the web, and from many sauce manufacturers themselves. This chart would not be possible without the hard work, input and testing of others.

Please keep in mind that Scoville ratings are not perfect. Pungency values for any pepper or hot sauce, stated in Scoville Heat Units, can be imprecise, due to expected variation within a species. This can be due to seed lineage, climate, sunlight, humidity, and soil. For instance, a Red Savina Habanero, which can reach an upwards of 577,000 Scovile units in an almost perfect pepper-growing climate such as New Mexico, may only reach 200,000 to 300,000 SHU in the cooler, damper New Hampshire. The inaccuracies described in the measurement methods above also contribute to the imprecision of these values. When interpreting Scoville ratings, this should be kept in mind.

How hot is hot? The spiciness of chile peppers, sauces, salsas, hot rubs, peppered cheese, snack chips, and other "hot" foods is all subjective. What is absolutely mouth-scalding to one person may be mildly hot to someone more used to hot foods. If you're a relative novice to the chile world, try to find something you have already tasted on the Scoville Scale Chart, such as Tabasco sauce or jalapeno peppers. If you find them mild, then you're probably ready for the more intense pungency of hotter sauces and peppers. If they set your tongue on fire, then stick to the weaker foods that contain only a small hint of heat.

Flavor trumps pure heat. Also remember that more than anything the whole culinary experience with hot peppers and hot sauces is what kind of flavor they add and how they compliment your dishes, not how much pure heat they can possess. This is not a horse race or a contest; just because something rates high on the Scoville Scale doesn't mean it's better than lower heat counterparts.

Photo courtesy of http://mallorcaphotoblog.wordpress.com/2007/08/22/garden-delights/





     Comments

Comment Mark
2008-11-06 20:24:00
fantastic Article, Scott. I didn't know the old fashioned way people had to subjectively taste sugar water just to find out the heat. It must have taken FOREVER.:) I wonder if there is some do it yourself kit that you can test out on some of your home grown peppers.
Comment Craig Rachow
2010-09-23 19:08:54
Great write up. i too am doing a information page about the Scoville Scale. Be hard to beat yours though, good job.
<a href="http://growingchillies.net/scoville-scale">Scoville Scale</a>
Comment Craig Rachow
2010-09-23 19:10:37
Sorry did not realise HTML was disabled. My Scoville Page is located at http://growingchillies.net/scoville-scale

Comment LuLu
2011-01-01 23:34:25
This is a wonderful article. I agree with the comment that it must have taken ages to test each pepper using the old 1912 method! Those must have been some dedicated chili lovers for sure. Thanks for all the great information you provide here. Some of the sauces are amazingly hot and I would never dare to try them myself-good to know ones limits!
Comment Jeff
2011-03-13 20:08:43
melinda's red savina sauce is not 577,000 units, maybe the pepper is but not the sauce, i own the sauce and its not that hot.
Comment jon whaley
2011-03-16 08:59:49
Hi Scott,

Great blog. I had all my sauces tested cia HPLC at a northeastern US college, twice in fact,. Each time the results came back different - some sauces were lower and others higher. And some sauices that I "knew" to be spcier came back as less spicy than another. The professor said that due to however much pepper was in each sample versus vinegar, etc would skew results and that he shook bottles as best he could to get good samples. I wanted very badly to be able to display the Scoville Heat Units for our sauces on the labels, but alas we cannot. So in my experience, you can test a pepper pretty easily but not a finished sauce. Has anyone else had similar (or better) results testing finished pepper sauces?
Comment Gus Tommer
2011-04-16 22:49:32
Very thorough. You obviously understand your subject, and this makes it easy to rely on your info. Thanx.

However, (isn't there always a 'however', LOL) I was wondering if it would be appropriate to update your 'Scoville Scale Chart for Hot Sauce and Hot Peppers', to...

'Pungency Scale Chart for Hot Sauce and Hot Peppers'. And include Scoville AND Gillett units.

I realize that everyone could just divide Scovilles by 15. But, who isn't lazy.

It would seam that Scovilles are to analog, what Gilletts are to digital. The Scoville method being admittedly subjective.

Besides, wouldn't it be easier to remember that pure Capcaisin is valued at 1,000,000 Gillets? While Frank's Red Hot is valued at 30. And Sriracha is valued at 147.

Either way. You're a great cheerleader to the study. I sincerely hope that you can influence sauce makers to adopt a method of labeling their products with info that will help buyers make decisions.


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