Chipotle paste is made from whole, dried chiles reconstituted with water then blended to a smooth paste. Use chipotle paste in sauces, soups, stews and even desserts. Mortia chipotle paste will be sweeter than meco, but meco paste will have a deeper, smoky flavor.
Companies that manufacture chipotle paste, or other chile pastes have to add citric acid to keep the paste from collecting toxic bacteria. Unfortunately it does affect the flavor so making your own is a good choice.
You can use either meco (ahumado chiles) or the small dark morita chipotle chiles. Soak 8 ounces of chiles in warm water. You can use a plate that will fit into your bowl to keep the chiles submerged. Soak the morita chiles for about 30 minutes or until soft. The meco chiles will require a longer soaking time.
Once the chiles are soft you drain off the soaking liquid but don't discard it. Strain the soaking liquid through a fine sieve and set aside.
Place the softened chiles in a food processor and whirl until they form a paste. Use some of the strained soaking liquid to thin the paste as desired.
You can use the paste immediately OR store it, refrigerated in a glass jar with a tight fitting lid. You can also freeze the paste. Refrigerated paste can be stored for a couple of weeks, frozen paste can be kept for several months without affecting the flavor.
If you don't have chipotle paste you can make your own, see method above, or use equal amounts of:
Chipotle chiles, citric acid