Any of the chili varieties harvested young, green in color, and with a sensitive texture. As they ripen, their color change from green to crimson to brownish-red and their flavor intensifies, getting spicier as they age.
Green chiles are often left on the vine until they start to turn at least half red. They may be left to linger on the vine until they are totally crimson or even desiccated in some situations. Jalapenos are usually picked when they are green and firm, though they can ripen to a red color.
Before using, green chiles are usually roasted. This roasting darkens the skin, which is subsequently removed, and gives the chili a smokey flavor. Jalapenos can be roasted, but they’re more commonly minced fresh and added to salsas, sauces, and pickles.