To make ketchup with fresh tomatoes, crush ripe tomatoes in a stock pot with onions, garlic and cayenne pepper, simmer for 30 minutes, let cool, then run the mixture through a food mill. Return to the pot and simmer until reduced by half, blend in batches, then simmer until it has the consistency of commercial ketchup. Add spices, brown sugar, Worcestershire sauce and vinegar, and simmer one last time to reduce to the desired consistency.
To make 8 to 10 pints of homemade ketchup with fresh tomatoes, wash and remove the stems from 1/2 bushel of ripe beefsteak tomatoes, quarter them and add to a large stock pot with 1 medium onion, 1 clove of garlic and 2 teaspoons of cayenne pepper. Crush the mixture to release some liquid, and simmer for 30 minutes. Let the mixture cool, then run it through a food mill in batches.
Return the mixture to the stock pot and simmer slowly for six to 12 hours to reduce the volume by half. Cool, blend in batches, then return to the stock pot, and simmer for another six hours until it reaches the consistency of store-bought ketchup. Add 3 cups cider vinegar, 2 tablespoons of Worcestershire sauce and 1 cup of dark brown sugar. Season with 3 tablespoons of salt, 1 teaspoon each of allspice and black pepper, 1 tablespoon each of cloves and cinnamon and 4 tablespoons of dry mustard. Simmer to reduce to the desired consistency.