This is the recipe from KatieC that I have, which does have vinegar in it (and it's excellent):

Smoky Chipotle Ketchup

Recipe By :Katie
Serving Size : 0 Preparation Time :0:00
Categories : Preserving

Amount Measure Ingredient -- Preparation Method
-------- ------------ --------------------------------
5 lbs. ripe tomatoes -- coarsely chopped
1 large onion -- finely chopped
1 large poblano chili -- finely chopped
2 jalapeno chilies -- coarsely chopped
4 canned chipotle chilies -- (2-5) chopped
1/2 cup cider vinegar
1 cup dark brown sugar
1 tsp. celery seed
1 1/2 tsp. mustard seed
1 tsp. black pepper
1 1/2 tsp. salt

Combine all ingredients in large, heavy nonreactive pot and bring to a boil over medium heat. Reduce heat and simmer 1 1/2 hours, stirring occasionally, until vegetables are soft and sauce is reduced by one-fourth.

Puree in a food processor or food mill, or use a stick blender. Strain through a sieve if desired. Bring to a boil and simmer until quite thick and dark brownish red.

Store in the refrigerator for up to 1 month, or process in a boiling water bath: 15 minutes at 0-1000 ft., 20 minutes at 1001- 6000 ft. and 25 minutes above 6000 ft.

Thank you so much. I must have omitted the vinegar when I copied it!

I saw your response on the Cooking Forum. I looked back at my notes and I had handwritten that I cut the sugar back to 2/3 cup and "might try 1/2 cup next time."

I must have thought the first batch I made (don't remember - it was years ago) was too sweet as well :-)