I used to make my own until I found the Trader Joe's. Here's the recipe I used:
12 pounds ripe tomatoes (this worked out to about 6-8 quarts, once peeled and seeded)
1 1/2 cups chopped onions
1/4 teaspoon ground red pepper (cayenne)
1 1/2 cups cider vinegar (whoops, I ran out and used half white vinegar. It turned out fine)
2 teaspoons cloves (whole or ground, doesn't matter)
3/4 tsp cinnamon
3/4 teaspoon whole allspice
1 heaping Tablespoon celery seeds
3/4 cups sugar
2 Tablespoons salt
Yields 4 pints
Wash tomatoes. Dip in boiling water for 30 to 60 seconds or until skins split. Dip in cold water. Slip off skins and remove cores. If desired, squeeze out seeds. [unfortunately, this is where most of the lycopene is...but doing this will significantly reduce processing time, as it takes a LONG time to cook the water out of tomatoes]
Quarter tomatoes into a stock pot or a large kettle. Add onions and red pepper. Bring to boil and simmer 20 minutes, uncovered. Cover, turn off heat, and let stand for 20 minutes.
Combine spices in a spice bag [if you don't have cheesecloth, a coffee filter works just fine!] and add to vinegar in a 1-quart saucepan. Bring to a boil. Remove spice bag and combine vinegar and tomato mixture. Boil about 30 minutes. Put boiled mixture through a food mill or sieve. Return to pot. Add sugar and salt, boil gently, and stir frequently until volume is reduced by one-half or until mixture rounds up on spoon without separation.
To can...Fill pint jars, leaving 1/8-inch headspace. Adjust lids and process in a hot-water bath [boiling water that covers the top of the jars by 1-2"] for 15-20 minutes.
What would you attempt to do if you knew you could not fail?
--Dr. Robert Schuller