A jalapeno pepper is a fruit produced by a cultivar of Capsicum annuum. It originated in Mexico and is popular in southwestern cuisine. This type of pepper is moderately hot, according to the official scale for measuring heat units. The burning sensation when the chili pepper is eaten is due to the compound capsaicin, which triggers the body to produce natural pain relievers known as endorphins.
There are a number of different species and cultivars of peppers in the genus Capsicum, which — along with tomatoes and potatoes — is in the nightshade family. These peppers vary greatly in their intensity of taste, with bell peppers being the mildest and other varieties having an extremely intense bite. There is an official scale to measure the degree of heat in chili peppers and compounds such as pepper spray. It is known as the Scoville Scale, and units are measured in Scoville Heat Units (SHU).
This scale was originally developed in the early 1900s to compare different intensities of heat by diluting the peppers in sugar water, and tasting the solutions. They were given a numerical rating based on how many times a chili extract had to be diluted before it lost its heat. Now, the measurement is done chemically, by high-pressure liquid chromatography (HPLC). Capsaicin, along with related molecules, is the compound responsible for the heat in peppers. Different pepper cultivars, with varying degrees of bite, have different SHU ratings, depending on their concentration of capsaicin.
With their mild taste, bell peppers have a rating of 0. In contrast, a jalapeno pepper has a rating of 3,000 to 6,000 SHU. This is in the same range as paprika and Tabasco® sauce. Poblano peppers only range from 500 to 2,500 SHU. Habanero peppers are several orders of magnitude hotter, with SHU ratings of 100,000 to 300,000. For comparison, pure capsaicin has a rating of 15 to 16 million SHU.
In the United States, jalapeno peppers are primarily produced in Texas and New Mexico. The fruit are 2-3.5 in (5-9 cm) in length when ripe, and are produced on plants that grow to be 2.5-3 ft (0.8-0.9 m) tall. Normally, a plant will produce 25 to 35 peppers.
The peppers are relatively easy to grow in a home garden. They are usually set out at the same time as tomato plants. They do best in warm temperatures and soil, and should not be planted until nighttime temperatures are 55° F (15° C) or higher. The plants should be spaced about one foot (0.3 m) apart. Jalapeno pepper plants require well drained, but moist soil. The plants should be fertilized once when they are planted outside, and again as they start producing fruit.
Cultivation practices can cause the heat intensity of this chili pepper to vary. If very hot jalapeno peppers are desired, one can stress the plants by only watering them weekly. The fruit turn red as they ripen. Unlike other types of chili peppers, jalapenos can be harvested and eaten when green or red. If smoked, a ripe jalapeno pepper is known as a chipotle.