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Understanding The Scoville Scale: Made Simple

Updated: Feb 27

chili peppers

There are an estimated 4,000 varieties of different chile peppers in the world today, with more being cultivated on a regular basis. All of which come with their own very unique flavor profiles and heat levels. With such a large variety of chile peppers that can range from almost no heat to burning your face off hot, it's a good idea to know what type of heat a chile pepper posses before attempting to eat it... or even touch it for that matter.

Which is where the Scoville Scale came into existence!

Whether you're a hot sauce aficionado or simply enjoy the occasional spicy dish, you've probably heard of the Scoville scale. But what is the Scoville scale? How does it work? And what do those numbers really mean in terms of heat?

We're gong to talk about everything you need to know about the Scoville scale, explained in-depth and easy to understand. Let's get right into it!

What Is the Scoville Scale?

The Scoville scale is a measure of the "hotness" of a chili pepper or anything derived from chili peppers, such as hot sauce. The scale is actually a measure of the concentration of the chemical compound capsaicin, which is what gives chili peppers their heat.

illustration of hot chili peppers

The Scoville Scale is a measured by what is called Scoville Heat Units (SHU). These units range on a spectrum from 0 (no heat at all) to 16,000,000+ (pure capsaicin).

The ranges of SHU is typically used to call a pepper mild, medium, hot, or extra hot and these will range from mild (50 to 2,500), medium (2,500 to 30,000), hot (30,000 to 100,000), and extra hot (100,000 to 500,000). Anything above that is super hot or extreme.

For example, a bell pepper would have zero Scoville Heat Units because it does not contain capsaicin. On the other hand, pure capsaicin would have 16 million SHU. To further note that bell peppers are the only member of the capsicum family that does not contain capsaicin, therefore registering as the only pepper with zero Scoville heat units.

The Scoville scale is also used to measure the heat of peppers. Because growing conditions (particularly humidity and soil) can have a significant impact on pepper Scoville ratings, they vary significantly.

A lot of variables can impact a pepper's Scoville rating, including seed lineage, maturity, and other conditions. The Scoville rating for a type of pepper may vary by 10 or more naturally depending on factors such as growth conditions (particularly humidity and soil).

How Does the Scoville Scale Work

The Scoville scale works by diluting a pepper extract with sugar water and then asking human testers to identify the heat level. The more sugar water is required to negate the heat, the higher the number of Scoville Heat Units that pepper contains.

So for example, a pepper with 100,000 SHU, the capsaicin mixture would need to be diluted 100,000 times. Which would allow the testers to no longer detect any spiciness!

While this method was mostly accurate, it was also quite subjective since it relied on human testers. In order to get more accurate results, a high-performance liquid chromatography (HPLC) machine is now used in addition to the Scoville Scale.

group of green and red chili peppers

Is the Scoville Scale Accurate

The Scoville Scale is regarded as accurate now as it doesn't solely rely on human taste testers. Since the method of measuring and rating capsaicin levels in hot peppers is also done through HPLC in addition to the Organoleptic test, it is considered accurate.

How Much Scoville Can a Person Handle

There is no real answer to this question since everyone tolerates pain differently. Some people can handle the spiciest peppers with ease while others can't handle anything more than a jalapeño.

With that being said, a study done in 1980, determined that a single dose of pure capsaicin would need to be 13 grams in order for it to be lethal for a person of about 150 pounds.

A study published in Drug and Chemical Toxicology found that for a person of average weight, in good health, would have to consume close to two quarts of Tabasco Sauce to be rendered unconscious. We don't suggest that you try that challenge, but you get the idea.

Where Did the Scoville Scale Come From

thai chili peppers

The Scoville scale was invented in 1912 by American pharmacist Wilbur Scoville. His method, which was called the Scoville Organoleptic Test, involved diluting an extract of chili peppers and givin to a panel of taste testers.

The testers would taste the solution and give their estimate as to how many times it would need to be diluted in order for them no longer to be able to taste its heat.

Wilbur Scoville was interested in the potential health benefits and uses that chili peppers possibly possessed. But he needed a way to quantify the research... thus creating the Scoville Scale through the Organoleptic Test.

What is the Hottest Chili Pepper in the World

As of 2017, the Carolina Reaper is the hottest chili pepper in the world with an average of 1,641,183 Scoville Heat Units (SHU). The Carolina Reaper was created by Ed Currie of the PuckerButt Pepper Company in South Carolina. This became certified as the World's Hottest Chili Pepper in the Guinness World Records.

The Reaper was originally rated at 1.5 million SHU but depending on a number of factors, a Carolina Reaper can hit a level of SHU as high as 2.2 million! Now that's HOT!!

While the Carolina Reaper is currently the reigning champion as the hottest chili pepper, there are always new peppers being grown and tested for their heat levels.

It's also important to note that the hottest chili pepper in the world is listed as the Carolina Reaper, but it is contested... by the Dragons Breathe Chile. Dragon's Breath has an average SHU of 1.6 million and can hit 2 million on the Scoville Scale.

So, it's possible that the title of World's Hottest Chili Pepper could be taken away at any time!

the scoville scale infographic showing heat levels for chili peppers

What is Pure Capsaicin

As we mentioned earlier, pure capsaicin is the active ingredient in chili peppers that makes them hot. Capsaicin is a colorless and odorless substance that belongs to a class of chemicals called vanilloids.

sign for capsaicin with chili peppers

When capsaicin comes into contact with your skin or mucous membranes (eyes, nose, mouth), it activates certain receptors that send pain signals to your brain.

That burning sensation you feel is your body's natural reaction to this "pain."

Which is why you need to be careful when handling chili peppers. If you were to touch an extremely hot chili pepper and then touch your face, you might be in for quite a spicy surprise.

Capsasicin Heat Levels

The most prevalent capsaicinoid in chili peppers is capsaicin. The following list displays the different types of chili peppers from least to most pungent.

  • Homodihydrocapsaicin - 8.6 Million SHU

  • Homocapsaicin - 8.6 Million SHU

  • Nordihydrocapsaicin - 9.1 Million SHU

  • Dihydrocapsaicin - 16 Million SHU

  • Capsaicin - 16 Million SHU

How Hot Are Chili Peppers?

The actual level of heat in chili peppers can vary significantly, even within the same species. For example, jalapeño peppers typically range from 2,500-8,000 SHU on the Scoville scale, while habanero peppers can range from 100,000-350,000 SHU.

Here are some common chili peppers and their approximate heat levels on the Scoville scale:

  • Bell pepper: 0 SHU

  • Pimiento: 100-500 SHU

  • Anaheim pepper: 500-1,000 SHU

  • Jalapeño pepper: 2,000-8,000 SHU

  • Serrano pepper: 10,000-25,000 SHU

  • Tabasco pepper: 30,000-50,000 SHU

  • Cayenne pepper: 30,000-50,000 SHU

  • Thai pepper: 50,000-100,000 SHU

  • Chiltepin pepper: 50,000-100,000 SHU

  • Scotch Bonnet: 100,000–350,000 SHU

  • Habanero pepper: 150,000-570,000 SHU

  • Ghost pepper: 850,000-1,000,000 SHU

  • 7 Pot Primo: 1,200,000-1,900,000 SHU

  • Trinidad Moruga Scorpion: 1,200,000 to 2,000,000 SHU

  • Dragon's Breath: 1,600,00-2,000,000+ SHU

  • Carolina Reaper: 1,600,00-2,000,000+ SHU

As you can see, there is a significant difference in the heat levels of various chili peppers. While some peppers (like the bell pepper) have almost no heat at all, others (like the ghost pepper) can be incredibly spicy.

What Determines the Heat Level of a Chili Pepper

hot sauce with chili peppers and spices

A number of factors can influence the heat level of a chili pepper, including where it was grown, what type of soil it was grown in, and whether or not it was irrigated.

The weather can also play a role in how hot a pepper is. For example, peppers grown in warm climates or affected by drought can have higher capsaicin levels than peppers grown in cooler climates.

The time of year can also influence a pepper's heat level. Peppers grown during the summer months are typically hotter than peppers grown during the winter months.

Finally, the ripeness of the pepper can also affect its heat level. Ripe peppers are usually hotter than unripe peppers.

The Scoville Scale Explained

The Scoville Scale is used to measure the heat of a chili pepper and has a scale that ranges from 0-16 million SHU. The official hottest chili pepper in the world is the Carolina Reaper, with a Scoville score of 2 million SHU. However, with so many chili pepper varieties and people like Ed Currie coming out with new ones, it's possible we may have a new world record soon.

Make sure to use our Scoville scale rating here to determine the heat levels of your next hot sauce or favorite foods with chili peppers!

If you guys have questions about the Scoville scale, chili peppers, hot sauces, or just about anything else spicy-related, leave a comment down below!

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