The Scoville Scale: How Hot Is That Pepper?

Let's begin with a given: The spiciness of food is entirely subjective. What's an eye-watering mouth-blaster to one may be blah and unsurprising to another. Still, it's helpful, before popping some stray pepper from your local grocer into your mouth, to have an idea of what might be considered spicy and what might not.

That's where the Scoville scale comes in. Named after a pharmacist named Wilbur Scoville, the scale was invented in 1912 to measure chemical compounds — capsaicinoids — that trigger that familiar burning sensation.

At first, the scale was little more than a taste test. Researchers took a sample and diluted it until no "spice" was detected, and measured it from there. The process — called the Scoville Organoleptic Test — had its limits. From New Mexico State University's College of Agricultural, Consumer and Environmental Sciences:

"It was not scientific by our standards," DeWitt says. "But then, they had nothing else."

Now, scientists extract the heat-inducing chemicals and measure their "pungency" by using High-Performance Liquid Chromatography. The relative "heat" is measured in Scoville heat units (SHUs). That stands as the primary means of determining spiciness in food (and the effectiveness, in another use of capsaicin — which is one of the major capsaicinoids — of pepper spray).

A bell pepper, for example, checks in on the Scoville scale at zero SHUs. Chomping down on a bell pepper would not prompt so much as a raised eyebrow or a reach for a glass of water. But that's the absolute bottom of the scale. From there, things get interesting.

Jalapeños, plenty spicy for a lot of people, rate relatively low on the Scoville scale (roughly around 5,000 SHUs). Above those are peppers like habanero, cayenne and Tabasco. For the truly adventurous, there's the Carolina Reaper, considered the hottest pepper in the world. At about 2 million SHUs, the Reaper rates, according to Chili Pepper Madness, somewhere between 175 and 880 times hotter than your garden variety jalapeño.

If you're asking yourself why someone would eat something that hot, it's a legitimate question.

"I think that there's a sort of a psychological addiction going on. And people who do like it hot and spicy tend to eat it constantly. Rarely do they give it up. You don't hear people say, 'I used to eat hot and spicy, and now I'm eating bland again,'" DeWitt says. "They just stick with what they like to death. Spiciness in their food gives them some sort of a thrill."

After his initial run-in with the green chili stew — after he finished sweating — DeWitt was hooked. He took his newfound interest and became a prolific author. He also now runs Fiery Foods & Barbecue Central, the Burn Blog and the annual Scovie Awards, which judges hundreds of products in 16 different categories. The contest drew 742 entries from 32 states and six different countries earlier this year.

Spices — and chilis overall — have become his life.

"Chili peppers don't necessarily help every single food that's out there," he says. "But I can't imagine some foods without them."

That's not to say DeWitt is necessarily a fan of super-spicy foods and sauces. Some are good, says the Pope of Peppers. Some are not. Personally, he doesn't stray far from the medium-hot end of the Scoville scale.

"There are sauces that are made with oleoresin capsaicin that are transformed into an oily substance ... It's so damn hot, but it has no flavor whatsoever. Well, it has flavor. It's terrible. That's bad hot spicy, in my opinion," he says. "You gotta have flavor. That's the key element that the Scoville scale does not measure. Flavor."

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