The guajillo benefits from toasting on a comal or other hot pan prior to use. Use this chile in salsas, sauces, soups and stews. Guajillo chiles are also used to make Harissa, a hot chile paste mixture used in Tunisian cooking.
The guajillo is considered a moderately hot chile or a 2 - 4 on a scale of 1 to 10 (10 being the hottest).
Guajillo are available most commonly dried whole, then powdered and sometimes paste. Beware of paste products. Read the label. Many contain extensive amounts of preservatives, artificial colorings and ingredients and the flavor is dreadful. Make your own paste (see recipes). See the where to buy section for purchasing information.
A few spice companies offer a guajillo powder. This is simply the dried whole chili, ground up into a fine powder. Use in recipes that call for guajillos and you don't want to take the time to use dried whole chiles.
The most commonly sold form of this chile is whole, dried. The chile can be toasted then ground, or hydrated and made it a sauce or paste.
If you are going to toast the chiles before you use them you can first wipe them with a moist towel to remove any dust or visible soil.
If you are going to soak them and blend them before use then simply tear them open; remove the stem, seeds and as much of the veins as possible. It easy to do this under running water which rinses the chiles at the same time.
Tear the chiles in pieces and place in a bowl. They are now ready for soaking.