Measuring the Heat of a Pepper – The Scoville Scale 100th Anniversary

 In researching for this blog I learned that 2012 is the 100^th anniversary of this heat measuring scale.  Wilbur Scoville developed the scale in 1912 while he was a Pharmacologist for Park-Davis.  The scale measures the spiciness or heat of a chili pepper in Scoville Heat Units or SHU.

Capsaicin

The Scoville Scale shows the level of capsaicin in a chili pepper.  Since I will be discussing capsaicin in my next blog, I will only touch on it here for reference.  To be scientific, our skin contains chemoreceptor nerve endings and capsaicin is a chemical compound found in chili peppers that reacts with these nerve endings giving a burning sensation.  In layman’s terms, capsaicin is that stuff in the pepper that makes your skin and tongue burn,

Scoville’s Test

Wilbur Scoville developed his organoleptic test to determine the level of heat in a pepper, or its amount of capsaicin.  This involved a tasting panel of five people who would determine whether they noted heat from the test sample.  (Now this gets a bit scientific folks so bear with me)

The test sample was made by taking capsaicin oil from a measured amount of dried pepper and making it into an alcohol extract.  A sugar water solution is then added little by little to the alcohol extract until the heat in the extract is no longer detectable.  The heat, or amount of capsaicin, of the pepper was the degree of dilution in order for the heat to be undetectable.  **The human subjectivity in this type of test made it less accurate, according to the scientific community, because it relied so much on the taste buds of the panel. **

Another Test

The more modern method of determining a peppers heat is the high-performance liquid chromatography test.  In my research, I found that this method uses a more purely scientific methodology to get its results.

The concentration of chemicals that produce the heat of the pepper are tested and measured.  A mathematical formula is then used to weigh these measurements according to the chemicals’ ability to produce a heat reaction.  The units for this test are the American Spice Trade Association pungency units or ASTA.

According to the information I found, an ASTA unit is one part capsaicin per million or 15 SHU.  Therefore, many believe that you can multiply the ASTA measurement of a peppers heat by 15 and get the SHU measurement.  Experts are not convinced that this is accurate and believe that the ASTA unit falls below the actual heat level of a pepper.

References: Wikipedia, www.scovillescaleforpeppers.com,