Jalapeño peppers (pronounced “hal-a-PAY-nyo”) are medium-sized chile peppers with a mild to moderate amount of heat, used to flavor everything from salsa to chili to salad dressing. Evidence of the earliest cultivation can be traced to the Mexican state of Veracruz, and the name jalapeño comes from Xalapa, the capital city. Still widely associated with Mexican cuisine, they are now grown worldwide and appear in fusion cuisine from Africa to Asia to the American South.

Jalapeños, a member of the nightshade family along with tomatoes, eggplant, and potatoes, get their heat from capsaicin, a chemical compound concentrated in the white pithy ribs of a pepper. Like most hot peppers, jalapeños vary in spiciness based on many growing factors, including the amount of sunlight and the pH level of the soil. Jalapeño peppers register between 2,500 and 8,000 Scoville heat units on the Scoville scale. Most commonly associated with Mexican cuisine, they fall between poblanos and habaneros on the heat index, and are typically among the least expensive of the fresh peppers at the grocery store.

Fresh jalapeños can be chopped, sliced, or diced, depending on your intended use. Prep a small dice to spread the heat evenly throughout a salsa or salad dressing. Slice jalapeño rings when you want to concentrate the heat into a bite, such as on nachos. You can reduce the heat level by removing the ribs and seeds. But use caution when working with fresh jalapeños—the oils can get on your fingers and cause discomfort if you touch your eye, nose, or other areas with sensitive skin.

Because they are relatively mild, jalapeño peppers can be eaten whole. Jalapeños stuffed with cheese, then breaded and deep-fried, are a popular appetizer in Mexican restaurants in the United States. Jalapeños can be pickled and served as a condiment, or roasted to tame the heat and bring out a slight sweetness. Prepared this way, they are a common topping for nachos and tacos. In addition, minced jalapeños are widely used in making salsas, sauces, and bottled hot sauces. Jalapeño peppers can be dried and smoked, in which case they are called chipotles. Ground chipotles can be used as a spice, and you can often find chipotles canned in adobo sauce in the Mexican food section of the grocery store, which makes a flavorful addition to chili or smoky addition to plain rice.

Jalapeño peppers have a vegetal flavor similar to a green bell pepper and a front-of-mouth heat effect. The spiciness can vary widely among individual peppers. Jalapeños are picked green and generally used in this unripened state. Jalapeños turn red as they ripen, both on and off the plant. They do not get any hotter as they ripen, but the flavor becomes somewhat fruitier and less grassy.

You can use jalapeños in pretty much any recipe calling for mild to moderate heat. They also make a good substitute for hotter peppers when you want to tame the flame in a dish. Keep pickled jalapeños in the fridge for a quick addition to tacos, nachos, and other dishes that would benefit from their assertive bite.

• Pickled Jalapeños
• Creamy Jalapeño Sauce
• Jalapeño Poppers

Jalapeños are one of the most common chile pepper varieties found in U.S. grocery stores. Look in the produce section among a display of chile peppers, which you can usually find with the bell peppers. Generally harvested when they’re between two and four inches in length, fresh jalapeños should be bright green, firm, and smooth with the stem still tightly attached. White striations near the stem end can indicate a hotter pepper. As they age, they may start to turn darker green and then red, with a slightly shriveled appearance. Avoid peppers that appear mushy or with a loose or missing stem.

You can purchase smoked and dried whole jalapeños, called chipotles; crushed or ground dried jalapeños; canned chipotles in adobo sauce; and jars of pickled jalapeños at Mexican grocers or in the Mexican foods section of most grocery stores. They’re also available fresh at farmers’ markets, where you may find less common varieties, and from bulk retailers and online grocery services. You could also consider growing your own jalapeños at home if you have a warm location with all-day direct sun.

Store fresh jalapeños in a paper bag or wrapped in paper towels in the crisper drawer of your refrigerator for up to a week. You can freeze whole jalapeños in plastic freezer bags or airtight containers, or chop them first and freeze them in individually portioned packages; for best quality, use within three months.

An average size jalapeño pepper contains about 4 calories but delivers 28 percent of daily value for vitamin C. They contain vitamins A and K, as well as B6 and folate. Jalapeños also provide dietary fiber, and the minerals magnesium, potassium, iron, copper, and manganese. Capsaicin, the chemical compound responsible for the heat, may help speed up metabolism and reduce hunger, relieve pain, aid digestion, and even lower blood pressure.

Jalapeños and serranos look quite similar, but serranos are generally smaller and thinner. Although both peppers fall under the “medium” heat index on the Scoville scale, serranos are, on average, three times hotter than jalapeños. But with a similar flavor, they make an easy swap depending on whether you want to increase or decrease the spiciness of a dish.