Homemade Ketchup

12 cups chopped tomatoes (I don't peel or seed, because I run through a food sieve {food mill would work, too}.)

1 cup chopped onions

1 cup chopped sweet pepper (I used green peppers.)

1 1/2 cups of vinegar

1 tablespoon celery salt

1 tablespoon kosher salt

1/4 teaspoon allspice

1/2 teaspoon pepper

3/4 cup sugar

1 stick of cinnamon

Combine tomatoes, onion, sweet pepper in a large stock pot.

Simmer until vegetables are soft.
Press tomato mixture through a food mill or sieve to remove seeds and/or skins.

Add vinegar, seasonings and cinnamon stick.

Bring to a boil in a stock pot.

Continue to boil rapidly until thickened, stirring often. 

Reduce quantity by half. This may take an hour or so. (I have a ruler that I place in the pot to measure how deep the sauce is...just keep measuring until it is half of starting quantity.)
Reduce heat and cook until thickened to your desired consistency. Again stirring often. This may take another hour or even several hours.
Remove cinnamon stick.
Ladle into jars (I used half-pints.) and seal.

Process for 10 minutes in hot water bath.

(If you are unsure of the canning process, there are many informative sites online. I am not a canning authority.)