Spice Up Your Life: A Guide to the Scoville Heat Scale

Developed in 1912, the Scoville Scale is used to rate the varying degrees of heat among chile peppers. But how does one rank something so seemingly objective? And how even rank them at all without the use of today's technology?

The reasons different chile peppers have different degrees of heat is due to the varying levels of capsaicin they contain. Their heat level, and thus their Scoville Scale score, is based purely on capsaicin content.

The Scoville Scale is divided into units that equal how many drops of sugar water it would take to dilute the heat of any given pepper. Sounds crazy, right? But keep in mind that this system was developed before computers could be used for analysis. So, the way it originally worked was that a panel of human taste testers would taste samples of a pepper that had been diluted in sugar water and keep track of how diluted the sugar water had to be before the pepper no longer tasted hot. This system has since been replaced by a process called High-Performance Liquid Chromatography, which assesses the chemicals in a pepper to measure how much capsaicin it contains. Even with new technology, the ratings aren't consistently accurate and much of this is due to the fact that there are many factors of a pepper's growing conditions that affect heat level such as soil variations and sunlight exposure (the more sunlight, the hotter the pepper).

The scale ranges from bell peppers with a score of 0 to pure capsaicin with a score of 15 million. Ghost peppers rank as the hottest food with a score of 1 million, and law enforcement pepper spray scores around 4 million. The Scoville Scale shows us that some peppers, like the ghost pepper, are so hot that they would never be widely used culinarily.