Heat gas grill on high. If using charcoal, do not use lighter fluid or the tomatoes and peppers will pick up that taste!
Rinse tomatoes and peppers. Core tomatoes and score a small "X" in the blossom end. Place tomatoes and peppers on hot grill and close lid. Turn frequently until peppers are charred and blistered and pretty much black all over. Tomatoes should have some blackened spots and blistered enough to remove the skins. Remove from grill. Place peppers in a bowl and cover with plastic wrap to steam for several minutes. Let tomatoes cool a bit on a cutting board until you can handle.
Peel and chop the tomatoes and place in a large bowl, being sure to include all the juices. You should have 7 to 8 cups of chopped tomatoes and juices from 5 pounds of tomatoes. You need at least 7 cups for safe canning purposes.
Wearing gloves, peel poblano peppers, the blackened skins should come right off. Pull out stem and discard. Cut poblanos open and remove seeds. Finely chop peeled and seeded poblanos. You should have 1 cup, and no more than 1½ cups, again, for canning purposes.
Place fire roasted tomatoes and poblanos in a large pot and add the remaining ingredients, adding just 1 tablespoon of sugar to start. Bring to a boil and then turn down and simmer for 10 minutes.
Using an immersion blender or food processor, carefully purée the salsa to a smoother consistency. In a food processor and working in batches, pulse 8 - 10 times and when all finished, return to the pot. Taste for seasonings and if too vinegary, add another tablespoon or so of sugar. If too sweet, add a little more vinegar to balance. Bring blended salsa back to a boil and simmer a few more minutes.
Have sterilized pint jars and lids and screw caps ready (they should all be washed in very hot water). Use a canning funnel and ladle hot salsa into jars, leaving a ½-inch head space. Wipe rims clean with a damp cloth and carefully place lid on and screw cap in place. Process in a boiling water bath for 15 minutes, then place upright on counter for 24 hours (see recipe notes for link to USDA Canning Guidelines). You will hear popping sounds as the jars seal. If after 24 hours, any haven't sealed, put in refrigerator to use now.
Store jars of salsa in pantry and use within a year. Enjoy!