Scoville Scale

Wilbur Scoville: Inventor of the Scoville scale
Wilbur Scoville

Meet Wilbur Scoville (1865 – 1942), inventor of the Scoville Scale.  Mr. Scoville was a twentieth century American pharmacist.  He is best remembered for creating the Scoville Organoleptic Test as a method of standardizing the measurement of heat in a chili peppers.  That method would later be called the Scoville scale.  The measurements would be called Scoville Heat Units (abbreviated as SHU).

Read more about Wilbur Scoville at Wikipedia

What is the Scoville Heat Unit

The original Scoville scale measured the number of Scoville Heat Units were measured by the taste of the person conducting the test.  A specific amount of dried pepper is soaked in alchohol to extract the capsicanoids.  The resulting tincture is added to a sugar water solution in ever increasing concentrations.  Each time, a panel of testers taste the solution.  The testing ends when three out of five testers can detect the flavor of the capsicanoids in mixed in the sugar water solution.

Although the traditional Scoveille scale was appropriate to the time, it had many draw backs which produced inconsistent results.  Although general results could provide significant indications of one pepper vs. the other, the test was much less than precise due to its subjective nature.  Not only does taste change from one panelist to the next, sensory fatigue yields higher and higher thresholds as testers become accustom to the sensation of heat.

Modern Scoville Scale Testing

Modern Scoville Scale testing has replaced human subjectivity with high-performance liquid chromatography (HPLC).  The scale for this method of measurement is American Spice Trade Association (ASTA) pungency units rather than Scoville heat units (SHU), however there is an easy mathematical translation.

One part capsaicin per million equals 15 SHU

Detractors of this method say it can produce results which are 20% to 40% lower than the original Scoville tests, however the original tests produced results which varied from lab to lab by as much as 50%.  So when considering products SHU side by side, it is very important that the exact method of measurement is considered.

What is the Hottest Pepper in the World

With two distinctly different methods of testing, tremendous variances between the two, and the wildly different results from the original Scoville test; this question remains wildly disputed.  If we set aside the variances resulting from growing conditions, the only scientific way to answer such a question would be to measure the various peppers side by side with the more modern method.  Unfortunately, that method is not widely available.  As a result, the battles and claims continue and will do so for much time to come.