Canned Plum Tomatoes

Written by Mary Nelen


Putting food by is the art of preserving the freshness of summer. Flavor as well as nutrition are benefits of taking the time to can summer food. According to the USDA, vegetables handled properly and canned promptly after harvest can be more nutritious than fresh produce sold in local stores.

In this recipe, plum tomatoes are cooked briefly to remove skins, cored, placed into jars and boiled in a canner creating a vacuum that removes air bubbles to prevent spoilage.

I use plum tomatoes, also known as “Roma” or “paste.”  They have less water than other tomatoes and make a great base for making everything from ketchup to tomato paste to various sauces all winter long.


RECIPE: Canned Plum Tomatoes: Yield: 1 dozen quarts. Time: 3 to 4 hours.


12- 1-quart Ball Jars with lids and bands, cleaned and warm

1 canner (21-quart) with canning rack

1 set canning tongs

1 canning funnel

1 small saucepan for lid sterilization

1 stockpot for scalding tomatoes

1 large bowl or cooler for ice bath

1 small set of tongs for removing lids from saucepan

1 plastic spatula to remove air bubbles

1 cutting board

1 small paring knife

Clean Dish Rags



36 lbs tomatoes, about 6 tomatoes per jar

24- tablespoons bottled lemon juice

12- teaspoons salt or 6 teaspoons of citric acid



Create this assembly line in your kitchen:

1)    Fill your canner ¾ full of water. Bring to a simmer, put the lid on and keep on a back burner until ready for use.

2)    Fill a stockpot with water to scald tomatoes in batches. Bring to a strong simmer.

3)    Fill a small saucepan half way with water and keep water almost to a boil.

4)    Wash tomatoes in batches and set aside for scalding

5)    Prepare ice bath for scalded tomatoes by filling cooler or bowl with water and ice.

6)    Place cutting board next to ice bath for skinning and coring tomatoes.

7)    Next to that, have a bowl ready for the skins and cores and line up 6 jars and bands.

8)    Place lids with rubber lining in sauce pan to sterilize.

9)    At the end of the line, have lemon juice, salt, measuring spoons and dishrags ready.


Wash all of the plum tomatoes in cold water. In batches, place in boiling water to scald. When splits appear in skin, after around 3 minutes, remove several tomatoes at a time with a slotted spoon or small colander and place in the ice bath.

When the tomatoes are cool enough to touch, remove skins and cores with a paring knife. Try to keep them intact, if possible. Using the funnel, fill each jar with tomato flesh only, leaving about 1” of headroom in the top of the jar. Add 2 tablespoons of lemon juice and one teaspoon of salt or 1/2 teaspoon of citric acid (to lower the Ph value) to each jar.

Use rubber spatula to remove air bubbles in mixture by sliding it around the edges of the jar. Wipe the neck of the jar clean with a dishtowel. Use a small set of tongs to remove a lid from the saucepan. Place lid on top of jar with a tap of the tongs and screw the band around it, “finger tight,” but not too tight. That will make it possible to allow air to escape during processing. The goal in processing is to eliminate all air to prevent contamination.

Bring water in canner up to a strong simmer. When all of the jars in the canning rack are filled with tomatoes and the lids are screwed on, place entire rack in water, turn heat up to high and process for approximately 45 minutes. Jars should be fully submerged with 2 to 3 inches of water above the jars. Add boiling water to bath if necessary.

When the jars have been processed in boiling water for the recommended time, turn off the heat and remove the canner lid. Wait 5 minutes before removing jars.

Using jar tongs, remove the jars one at a time, being careful not to tilt the jars. Carefully place them directly onto a towel or cake cooling rack, leaving at least one inch of space between the jars during cooling. Avoid placing the jars on a cold surface or in a cold draft.

Repeat this process until all of the tomatoes have been processed. Leave jars undisturbed for 24 hours. You will hear a popping sound when the seal is made.

To check to see if a seal has been created in the jar, press on center of cooled lid. If jar is sealed, the lid will NOT flex up or down. If it does flex up or down, refrigerate and use within 2 weeks. Store sealed jars in cool, dark place for up to one year.

Congratulations! You have just put canned tomatoes. Enjoy this summer’s bounty all year long. See for additional tomato recipes.