Roast peppers in a 450° F. oven for 20-25 minutes until the skin blisters. Immediately place all of the peppers in a bowl (or plastic bag) and cover for about 20-30 minutes. Remove the skins and seeds from the peppers and discard. Chop the flesh of the peppers into bite size pieces and place in a pot with garlic and enough water to just barely cover the peppers. Bring to a boil and season with salt. Turn down to a simmer and allow to cook for several hours.
The peppers should break down so that you are left with a chunky puree that is not too watery. You may puree the peppers for a smoother consistency if you like. Allow to cool.

This will freeze well for several months