Can we take a moment to appreciate the culinary power of the world’s spiciest peppers? Whether appearing in sauce, ground spice, or roasted form, the spicy pepper brings a welcome bit of heat and complexity to any food (not to mention margaritas!). If you’ve ever wondered how to identify your favorite peppers — from pleasantly piquant to dangerously spicy — look no further. While there are thousands of pepper varieties out there, we’ve compiled a list of some of the ones most commonly used in cooking and ones that take heat to the next level (and occasionally feature in competitive pepper-eating contests!), and we’ve even included the spiciest pepper in the world!
First and foremost, let’s settle a common misconception: Although spicy peppers have a distinctly savory taste, the popular produce is not a vegetable. Known in the nightshade family as the genus Capsicum, peppers are technically a fruit. The flesh of a pepper is the flower of the plant and can be enjoyed raw, cooked into a sauce, or ground into spice, depending on the pepper variety.
What Makes Peppers Spicy?
Believe it or not, a pepper’s spice level is tied to an evolutionary survival tactic. Peppers contain the chemical compound capsaicin, which, when consumed by mammals, sends messages through our tongue’s receptors to warn us of its potency. “This type of receptor is also activated by pain and heat, and chemicals such as ethanol and acid,” says Dr. Irwin Donis-González, co-director of the Postharvest Research and Extension Center at the University of California, Davis, of the sometimes intense experience of eating a particularly spicy pepper. “The role of this receptor is to carry tissue-damaging information,” adds Dr. Donis-González. “And because of this, the brain detects the presence of capsaicin as pain.”
While different types of peppers contain varied amounts of capsaicin (and some, such as bell peppers, don’t at all!), there are ways to dampen the impact of a spicy pepper. Most capsaicin is concentrated in the pepper’s connective pith (not the seeds!). “Different components [of the pepper] contain significantly different levels of capsaicin — those with higher capsaicin levels will generate a higher spicy mouth feeling,” says Dr. Donis-González. The skin and flesh of a pepper contains about 1% of its capsaicin, while the pith contains approximately 87% and seeds contain 12% of its capsaicin, adds Dr. Donis-González. If you’d like to reduce the level of capsaicin and tone down your pepper’s pop of heat, simply remove the pith and seeds and eat the outer portion of the pepper only.
How Are Peppers Classified as Spicy?
A pepper’s heat level is measured by the Scoville Scale, a classification system invented by pharmacist Wilbur Scoville in 1912 as the Scoville Organoleptic Test. The test — in which chili peppers are consumed by trained testers and diluted until the participants cannot measure any “heat” left — organizes peppers into categories by their Scoville Heat Level, or SHU. Peppers are classified by a range of SHU due to the discrepancies in subjective human testing as well as the variance in capsaicin in peppers of the same species.
A Guide to the World’s Spiciest Peppers
Mild- to Medium-Spicy Peppers
Hot Cherry Pepper
SHU level: 2,500–5,000
Small, round, and red, the moderately spicy hot cherry pepper is similar in appearance to the sweet Peppadew and pimento. Like the Peppadew and pimento, the slightly more spicy cherry pepper is most commonly pickled and appears in charcuterie platters and antipasto dishes, and as a sandwich topping.
Jalapeño Pepper
SHU level: 2,500–10,000
Bright green jalapeño peppers are one of the most well-known spicy peppers (although their SHU levels are comparatively mild to other spicy varieties!). Originating from Mexico, jalapeño peppers are used in everything from spicy margaritas and stuffed poppers to dips and tacos.
Chipotle Pepper
SHU level: 5,000–10,000
Chipotle peppers are jalapeño peppers that have been smoked and dried, resulting in their rich, earthy flavor profile. Chipotle is often ground into powder and used in Mexican and Tex-Mex cuisine like tacos and burritos, or in adobo sauce.
Aleppo Pepper
SHU level: 5,000–10,000
Commonly found in ground spice form, the spicy and fruit-forward red Aleppo pepper is most frequently used in Mediterranean and Middle Eastern cuisine to season dips, kebabs, and vegetables.
Serrano Pepper
SHU level: 10,000–25,000
Slightly lighter in appearance than the jalapeño pepper, the green serrano originates in Mexico and is commonly included in salsa verde and guacamole, and sautéed or roasted in tacos and fajitas.
Tabasco Pepper
SHU level: 30,000–50,000
Small and bright red, tabasco peppers originate in Mexico and have a spicy, smoky flavor profile. They are most frequently processed into sauce and added to everything from eggs to seafood to soup for a bit of heat.
Bird’s Eye Chili Pepper
SHU level: 100,000–225,000
Originating from Southeast Asia, the small, bright red bird’s eye chili pepper packs a serious punch. The bird’s eye chili has several sub-varieties and a fruit-forward flavor profile, and is frequently ground into pastes or powder and employed in Thai curries and Vietnamese soups and stews, and served raw alongside roasted meats.
Scotch Bonnet Pepper
SHU level: 150,000–325,000
The mighty Scotch bonnet from the Caribbean is small, ranges from yellow-orange to bright red, and does indeed resemble its namesake accessory. Its tropical, fruity flavor notes are a key to the perfectly piquant Jamaican jerk chicken and Jamaican curry chicken and also frequently used in Caribbean sauces and marinades.
Ghost Pepper
SHU level: 600,000–1,041,427
Also known as the bhut jolokia, the ghost pepper packs a scary level of heat. Once the hottest pepper in the world according to the Guinness Book of World Records, the pepper originates from Northeast India and is named for the language’s word for “ghost.” Ghost peppers are small, red, and wrinkly in appearance and have a fruity, smoky flavor mixed into all of that (painful!) heat. Due to their extreme SHU levels, ghost peppers don’t appear in many restaurant or home recipes, but are available at select grocery stores and can be made into hot sauce or super-spicy salsa with proper precaution and protective gear.
The Spiciest Pepper in the World
Carolina Reaper or Pepper X?
SHU level: 1,500,000–2,200,000 (Reaper) and 2,693,000 (Pepper X)
Fear the Reaper. The small, bright red, and pockmarked pistol packing a truly terrifying SHU level was known as the spiciest pepper in the world — until a new greenish-yellow hybrid variety known as Pepper X dethroned it in October 2023 with a SHU level of over 2,693,000. That said, the dethroning is not without controversy — according to some pepper experts, Pepper X and Carolina Reaper creator Ed Currie’s refusal to release his seeds has sparked doubt about the veracity of Pepper X’s SHU claims. We don’t advise you to decide for yourself — it could be a less-than-pleasant experiment, to say the least, unless you’re a trained taster. It goes without saying, but Carolina Reaper Peppers and the brand-new Pepper X are not commonly consumed in everyday cuisine!