In commercial ketchups, sweetening is the second ingredient—after tomato concentrate and before the garlic and onion powders. One taste of a true tomato ketchup simmered from fresh ingredients will make you understand why people savor homemade ketchup not just with hamburgers and French fries but with steaks as well.
Combine in a large nonreactive pot over medium heat and simmer, stirring occasionally, until very soft:
      14 pounds ripe tomatoes, peeled and chopped
      8 medium onions, sliced
      2 red bell peppers, diced
Puree through the medium blade of a food mill or push through a coarse-mesh sieve, then return to the pot. Stir in:
      3/4 cup packed light brown sugar
      1/2 teaspoon dry mustard
Tie in a moist square of cloth and add to the tomato mixture:
      1 3-inch cinnamon stick
      1 tablespoon whole allspice
      1 tablespoon whole cloves
      1 tablespoon ground mace
      1 tablespoon celery seeds
      1 tablespoon black peppercorns
      2 bay leaves
      1 clove garlic, peeled
Bring the mixture to a rolling boil, then reduce to a simmer. Continue to cook, stirring often and carefully so it does not scorch, until the sauce is reduced by half. Remove and discard the spice bag. Stir in:
      2 cups cider vinegar
      Canning salt or pickling salt to taste
      Ground red pepper to taste (optional)
Reduce the heat and simmer, stirring almost constantly, for 10 minutes. Can while hot; or let cool, then cover and refrigerate for up to 1 month.