Some of the most common hot pepper varieties are jalapeno, serrano, cayenne, habanero and bird's eye chiles, also known as Thai chiles. There are hundreds of varieties of chile peppers. The level of heat in each variety of pepper is measured by the Scoville scale.
Jalapeno peppers are one of the most common hot peppers. Chipotle peppers are smoked, ripe jalapenos. Jalapenos are green or red, two to four inches long and have a Scoville rating of between 2,500 to 10,000. They are used in salsa, stuffed and pickled and are common in Mexican cuisine.
Serrano peppers are hotter than jalapenos, with a Scoville score of 10,000 to 20,000.They can be green, red, orange or yellow and are one to three inches long. Serrano peppers are used in Mexican and Thai cooking.
Cayenne peppers are thin, red peppers with a Scoville rating of 30,000 to 50,000. Cayenne is most common in its dried, ground form, known as cayenne pepper. Cayenne pepper is the main ingredient in chili powder, used in many Tex-Mex dishes.
Habanero peppers are small and bulbous and are usually orange or red. Habaneros are one of the hottest peppers on the Scoville scale, with a score of 100,000 to 350,000. They are popular in Mexico and the Caribbean, and they are used to make hot sauces.
Bird's eye peppers are tiny, slender and pointy, usually less than one inch long. They rate between 50,000 and 1000,000 on the Scoville scale. Bird's eye peppers are commonly used in stir-fry recipes and Southeast Asian cuisine.