How is the heat level of chillies measured?
In 1912, Wilbur Scoville, a chemist under the employ of Parke Davis Pharmaceutical Company, developed a method to measure the heat level of chillies. The test is called the Scoville Organoleptic Test. In his original testing, Mr. Scoville blended various pure ground chillies with a sugar-water solution. A panel of testers then sipped the concoctions in increasingly diluted concentration, until they reached the point at which the solutions no longer burned the mouth. A number was then assigned to each variety of chillie based on how much it needed to be diluted before the heat was no longer tasted. This measurement of millions of drops of water-sugar solution is then translated into Scoville Heat Units (SHU) in multiples of 100.