The Untold Truth Of The Scoville Scale

The Scoville Scale was named for the scientist Wilbur Scoville, who pioneered the scale in 1912, according to Chili Pepper Madness. Scoville wanted a more scientific method of measuring the heat of peppers and chilis, so he devised a way of calculating the Scoville Heat Units, or SCHs, of spicy foods. Technically, the test is called a Scoville organoleptic test, and it measures the number of dilutions a chili pepper required before testers could no longer taste the heat.

To get an accurate number, Scoville ground the peppers up and mixed them with sugar water. A panel of taste testers then sampled the sugar-pepper water, ranking the heat levels as Soville diluted it. Bit by bit, Scoville added water to the concoction, until it was so diluted that the testers could no longer detect any heat at all. The degree of dilution was then divided into multiples of 100, and the resulting number would then be the pepper's assigned Scoville Heat Unit.

Today, Scoville Heat Units are measured using High Performance Liquid Chromatography

The concept of the test has remained pretty much the same for over a century, although these days, scientists no longer rely on human testers to rank the peppers' spiciness. "It's easy to get what's called taster's fatigue. Pretty soon your receptors are worn out or overused, and you can't taste anymore. So over the years, we've devised a system where we used what's called high performance liquid chromatography," New Mexico State University horticulture professor Dr. Paul Bosland told Smithsonian.

Instead, scientists can now measure the parts per million of heat-causing alkaloids in a pepper. That measurement, divided by 16, gives them the pepper's official Scoville Heat Unit. 

The Scoville Scale starts off with the kind of mild peppers most people eat every day, like sweet peppers, which have only around 5 Scoville Heat Units, and bell peppers, which contains no capsaicin at all, according to Alimentarium. At the very top are the brutally spicy, practically inedible peppers like Trinidad Moruga Scorpion, which measures at 1.4 million heat units, and the Carolina Reaper, which has a whopping 1.5 million SHUs and is ranked in the same class as law enforcement grade pepper spray, which usually has between 2 million and 5.3 million SHUs.

Resiniferatoxin is the hottest chemical on the Scoville Scale

The Carolina Reaper, however, is not even at the top of the scale. A new chemical, Resiniferatoxin, reigns even above pure capsaicin, at a shocking 16 billion SHUs, 10,000 times hotter than the Carolina reaper and over 900 times hotter than capsaicin itself.

According to Wired, Resiniferatoxin is a chemical found in a plant called Euphorbia resinifera, or resin spurge. Native to Morocco, this cactus-like plant is so pungently spicy that eating it may cause chemical burns and even death, due to the fact that it is so hot it kills off the body's nerve endings.

While eating it may be suicidal, it may actually be able to help save lives in another way. Injecting the toxin into aching body parts will kill off the sensory neurons that cause pain, which means this plant has the potential to completely revolutionize the painkiller industry and maybe even make opioids obsolete in the future.

So the Scoville Scale isn't all about finding the hottest peppers so you can impress your friends with how much pain you can endure. It may even help scientists figure out new ways to eliminate pain as well.