Substituting peppers for onions wouldn't work - a real change in pH - but yes, you can reduce low acid ingredients. NCHFP calls for 1 1/2 c onions and 1 cup chopped peppers so there is no safety issue in reducing the onions to 3/4 cups and the peppers to 3/4 cups.

The store bought beans and tomatoes, when that is your only choice, is safe as they have citric acid and stabilizers added to them. But the reprocessing of them does affect quality and texture. Why not use the dried beans as called for rather than the canned ones?

I don't know of any reason why you can't do the burger on the grill. It will drain off the fat as it cooks and that is the point - to remove as much fat as possible. Just make sure everything gets mixed together and is hot before packing the jars.

Dave

Thanks Dave, I do plan on using the dried beans but I just wondered if you could use the canned. I am glad that the grilled hamburger will be okay, that is what we use for our chili just gives it a different flavor that we like. can you substitute some of the onions or peppers for some celery, just wondered, I understand what you said about the pH change in your post about the peppers & onions.