Make sure that they are firm to the touch and the skin is smooth. Once they are wrinkled, their crisp texture and fresh flavor are gone, and they develop an earthy taste.
* Use serranos, jalapeños, poblanos and verdes while they are still green unless the recipe states otherwise.
* Use them as soon after purchasing as possible. Otherwise, store them for up to two weeks wrapped in a dry terry-cloth towel inside a paper bag in the refrigerator or a cool dark place. Do not freeze.
* Dried Chiles
Whenever possible, buy loose, rather than packaged, chiles so that you can examine them closely. Besides, they are much cheaper. Accustom yourself to the shape of the chiles so that you can be sure you are getting the correct one. Packaged chiles in particular are often mislabeled.
* Select chiles that are still a little flexible and not dried to a crisp. If only crisp ones are available, place them on a warm pan before using; as they heat through they will become pliable. On the other hand, do not buy damp dried chiles, for it means that either they have been incorrectly stored or the vendor has dampened them so that they will weigh more. Chances are the moisture will cause mold to form.
*Store in a cool, dry place, or freeze in a freezer bag.
* Check your dried chiles to make sure the fruit moth has not damaged them. If it has, the chiles' skin will be translucent, and there will be dark eggs just visible that will hatch greedy caterpillars.