The jalapeño is a medium- to large-sized chili pepper which is prized for its warm, burning sensation when eaten. Ripe, the jalapeño can be 2–3½ inches (5–9 cm) long and is commonly sold when still green. It is a cultivar of the species Capsicum annuum originating in Mexico. It is named after the town of Xalapa, Veracruz, where it was traditionally produced. 160 square kilometers are dedicated for the cultivation of jalapeños in Mexico alone, primarily in the Papaloapan river basin in the north of the state of Veracruz and in the Delicias, Chihuahua area. Jalapeños are also cultivated on smaller scales in Jalisco, Nayarit, Sonora, Sinaloa and Chiapas.
As of 1999, 5,500 acres (22 km2) in the United States were dedicated to the cultivation of jalapeños. Most jalapeños were produced in southern New Mexico and western Texas.
Jalapeños are a pod type of Capsicum. The growing period for a jalapeño plant is 70–80 days. When mature, the plant stands two and a half to three feet tall. Typically, a single plant will produce twenty five to thirty five pods. During a growing period, a plant will be picked multiple times. As the growing season comes to an end, the jalapeños start to turn red.
Once picked, individual peppers ripen to red of their own accord. The peppers can be eaten green or red.
The jalapeño rates between 2,500 and 10,000 Scoville units in heat. In comparison with other chili peppers, the jalapeño has a heat level that varies from mild to hot depending on cultivation and preparation. The heat, which is caused by capsaicin and related compounds, is concentrated in the veins (placenta) surrounding the seeds, which are called picante. — deseeding and deveining can reduce the heat imparted to a recipe that includes jalapeños. They also have a distinct acidic taste.