Drying chiles is more than just a way to preserve their flavor to use year-round. Dried chiles have a distinctive flavor (the dried and fresh version of the same species often have different names, as well as flavor profiles so different that one might never guess they started off as the same chile!) and they are used in a different way than fresh chiles. Dried chiles are sometimes soaked in hot water to reconstitute them and then chopped or puréed (often in sauces or added to stews); other times they are toasted and ground into a powder and added to dishes that way. Learn about different kinds of dried chiles below.
Ancho & Mulato Chiles
Hold on to your hats. This is where chile taxonomy goes from complicated to just plain weird. Ancho chiles and mulato chiles are both dried poblano chiles. When poblanos are dried they either become anchos, which are a bit red, or mulatos, which are almost black. And — get this — there is no way of knowing which one the fresh poblano is going to become! In either case, the dried ancho or mulato tends to be significantly hotter than the fresh green poblano.
Chiles de Arbol
Chiles de arbol are widely available, especially in stores with Mexican food sections. They are small and stay bright red when dried. They are not particularly flavorful so much as just plain hot. They add heat to soups, stews, and sauces. Chiles de arbol are usually used whole, added to sautées or thrown into stews or soups.
Chiles secos means "dried chiles" in Spanish, but the term is usually used to refer to serrano chiles that have been allowed to ripen until red and then dried. Chiles secos are a wee bit bitter, with only the slightest whiff of serranos' characteristic grassy flavor left. They are not terribly common in the U.S., although they often can be found in Latin American markets.
Chipotles are ripe (red), dried, smoked jalapeños. They become a bit sweet and very hot, with plenty of smoky flavor. They are sold dried (after all that drying and smoking they really look remarkably dessicated), but chipotles are more commonly available in cans packed in a vinegary tomato sauce called adobo. The chiles and the sauce are quite hot, with tons of layers of flavor. Some recipes even call for the adobo sauce chipotles are packed in as a separate ingredient!
Gaujillo chiles are long and tapered. They are a deep maroon color and are fairly hot. They are usually soaked to soften them then pureed into sauces or added to stews or marinades for heat and deep flavor.
Pasillas are long and thin and almost black in color. They can be very hot, so the heat-phobic should beware. Pasilla chiles add a distinctive, slightly astringent flavor to dishes, making them well suited to balancing out heavy stews and rich sauces.
Pequín chiles are also known as chiles pequeños, or "little chiles." And they are little — just about half an inch long. They are a bright orange-red and have a lovely sweet, smoky flavor along with their bright heat. They tend to be used whole, simmered in sauce or stew to add flavor.