How do I? ...Can Tomatoes

Selecting, Preparing and Canning Tomatoes

Tomato Paste

  • 14 pounds Roma- or paste-type tomatoes  
  • 1 teaspoon citric acid
  • 2 bay leaves
  • 1 teaspoon canning or pickling salt
  • 1 clove garlic (optional)

Yield: About 8 or 9 half-pint jars

Please read Using Boiling Water Canners before beginning. If this is your first time canning, it is recommended that you read Principles of Home Canning.


1.  Wash and rinse half-pint canning jars; keep hot until ready to fill.  Prepare lids and ring bands according to manufacturer’s directions.

2.  Rinse tomatoes thoroughly under running water and remove cores; do not peel. Chop tomatoes into ½- to ¾-inch pieces.  Place in stockpot; cover and bring tomatoes to a boil.  Stir as needed to prevent burning. Reduce heat, remove lid and cook slowly (simmer) for about 1 hour until volume is reduced by half.  Stir frequently to prevent sticking and burning. 

3. Press cooked tomatoes through a fine sieve (or food mill with fine blade).  (Do not use a blender or food processor, as these will incorporate undesired air into the tomatoes.)

4.  Return sieved tomatoes to stockpot. Stir in citric acid thoroughly. Add and stir in any or all of salt, bay leaves, and garlic clove (if desired).  Continue cooking slowly on medium heat, uncovered, until thick enough to round up on a spoon and volume is reduced again by half, about 2-½ hours. Stir frequently to prevent sticking and burning. Be careful of spattering which could burn your skin as you stir.

5.  Remove bay leaves and garlic clove if used.  Fill hot paste into clean, hot half-pint jars, leaving ½-inch headspace. Remove air bubbles and adjust headspace if needed. Wipe rims of jars with a dampened, clean paper towel. Apply and adjust prepared canning lids. 

6.  Process in a boiling water canner according to the recommendations in Table 1.  Let cool, undisturbed, 12 to 24 hours and check for seals.

Table 1.Recommended process time for Tomato Paste in a boiling-water canner.
  Process Time at Altitudes of
Style of Pack Jar Size 0 - 1,000 ft 1,001 - 3,000 ft 3,001 - 6,000 ft Above 6,000 ft
Hot Half-pints 45 50 55 60

Note:  The citric acid in this recipe needs to be added into the sieved tomatoes before they are cooked down into paste (Step 4). Adding it to the jars, as with other canned tomato products, does not allow for adequate distribution of the acid throughout the product. The ratio of citric acid to pounds of tomatoes must be kept consistent.

Developed at The University of Georgia, Athens.  Released by Elizabeth L. Andress, Ph.D., Department of Foods and Nutrition, College of Family and Consumer Sciences.  May 2015.

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