Author and culinary arts teacher James Peterson suggests chopping the firm ingredients very finely. Several ingredients that you need to chop finely include chiles, garlic, and onions. For softer ingredients, like tomatoes, you can prepare them coarsely. If you want a chunky textured salsa, use a food processor, but if you want it smooth, use a blender.

Combine ingredients in a large saucepan. Bring to a boil, then reduce heat and simmer, stirring frequently until thick (about 1 hour). Ladle hot mixture into pint jars, leaving 1/2-inch headspace. Adjust lids and process in boiling-water canner for 15 minutes at 0–1,000 feet elevation, 20 minutes at 1,001–6,000 feet, and 25 minutes above 6,000 feet.
I don't like messing with a water bath and bowl of ice water to peel the tomatoes; instead, I cut them in half and place them cut side down on a large baking sheet (really cram them in there in a single layer). I broil them for 3-4 minutes until the skins begin to pucker. Once they come out of the oven, the skins will wrinkle and peel right off and the baking sheet is easily cleaned. For this recipe, I use about three sheet pans of tomatoes (again the exact amount will depend on variety).
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.
Hi, I came across your recipe and am eager to try it, but have never done any canning before, so I dont have a canner. I’ve tried doing a little research, and am a little overwhelmed, so I thought I would ask the source. Is this recipe safe to can in a water bath method, just covering it with boiling water for the recommended time in a big pot? Forgive me if that is a stupid question! Thanks so much, I cant wait to try it!! 
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