Canned Diced Tomatoes

Ingredients

• 9.53 kg (21 lb)plum (Roma) tomatoes, peeled, cored and diced
• 120 ml (8 tablespoons)bottled lemon juice
• 20 ml (4 teaspoons)salt

Instructions

1. 1

   Prepare the jars

   Wash the jars and screw bands in soapy water, then rinse them thoroughly under hot running water. Put the clean jars on a baking tray in an oven preheated to 200°F (about 93°C), and set the bands aside. Boil a kettle, pour the water into a clean glass bowl and carefully submerge the sealing discs; leave them there.

2. 2

   Peel the tomatoes

   Bring a small pan of water to a full boil. Lightly score an X through the skin on the bottom of each tomato, without cutting deeply, and set a bowl of ice water in the sink. Blanch about four tomatoes at a time for 30 seconds, lift them out with a slotted spoon and transfer them straight to the ice water. Repeat until all the tomatoes are blanched. When the skins have opened at the cuts, peel them off by hand and put the tomatoes in a clean bowl. Chop them, removing and discarding the cores.

3. 3

   Fill the jars

   Take the jars out of the oven. Using a funnel, ladle in the diced tomatoes, keeping the rims clean. Pack them firmly, pressing the tomatoes down with a clean spoon.

4. 4

   Add lemon and salt

   Add 1 tablespoon of bottled lemon juice and 1/2 teaspoon of salt to each jar.

5. 5

   Wipe the rims

   Use a damp paper towel to clean each jar rim, making sure no tomato is left on it.

6. 6

   Position the discs

   Use a magnetic lid lifter to take the sealing discs from the hot water. Place one directly on each jar without touching its underside.

7. 7

   Tighten the bands

   Screw on the bands until firm, using only your fingertips and not forcing them tight.

8. 8

   Prepare the canner

   Set up your pressure canner according to the instructions for its specific make and model.

9. 9

   Load the canner

   Use a jar lifter to place the jars in the canner, then secure the lid.

10. 10

    Process the jars

    Process for 30 minutes at 10 pounds (69 kPa) using a weighted gauge, adjusting pressure for altitudes above 1,000 feet as required. Start timing only once the canner reaches full pressure. When processing is complete, turn off the heat and let the pressure fall naturally.

11. 11

    Remove the jars

    Lift each jar out carefully with the jar lifter. Keep the jars upright and do not wipe them dry. Set them on a wire cooling rack covered with a clean tea towel.

12. 12

    Cool and store

    Leave the jars undisturbed to cool for at least 12 hours. Once cool, wipe away any residue on the outside, label the jars and store them in a cool, dark cupboard.

What are canned diced tomatoes?

Canned diced tomatoes are peeled, chopped tomatoes preserved for use in dishes such as soups, sauces and stews. Home canning has long been a way to keep seasonal produce available beyond the harvest.

This version uses plum tomatoes, bottled lemon juice and salt. The recipe’s pressure-canning directions should not be treated as a universal process: use current, tested guidance suited to your tomatoes, jar size, canner and altitude.

Nutrition and macros by portion

The nutrition label shows one serving as written: 54 calories, 3g protein, 12g carbs, 1g fat.

The recipe’s supplied nutrition per serving is 54 kcal, with most of the carbohydrates coming from the tomatoes; the lemon juice and salt contribute little energy. Serve a portion alongside a protein-rich food and a vegetable or wholegrain side for a more rounded plate.

Choosing the tomatoes

Plum tomatoes: Their firm flesh is convenient for chopping and packing into jars. Choose sound tomatoes and discard any that are spoiled or damaged.

Ripeness: Ripe tomatoes give the batch its flavour, but very soft fruit can be harder to handle neatly during peeling and packing.

Peeling and chopping

Score lightly: A shallow X gives the skin a place to split without cutting far into the flesh.

Cool promptly: The ice bath halts the blanching and makes the loosened skins easier to remove. After peeling, remove the cores before dicing.

Keeping jar rims clean

Leave the rim clear: Tomato residue on the sealing surface can interfere with a clean closure, so use the funnel while filling and wipe each rim before fitting a disc.

Pack carefully: Press the tomatoes down with a clean spoon as the method directs, but avoid smearing the rim while doing so.

Pressure-canning details

Use tested guidance: Processing time and pressure depend on factors including the canner, jar size and altitude. Confirm the correct process for your setup with a reliable, current home-canning source before making this batch.

Altitude: The recipe says to adjust pressure above 1,000 feet but does not give the adjustment. Do not guess; check the canner instructions and tested guidance for your altitude.

Cooling and doneness cues

Natural depressurisation: The method calls for turning off the heat and letting the canner depressurise on its own. Follow your canner’s instructions before opening it.

Cool undisturbed: Keep jars upright on the covered rack for at least 12 hours. Do not retighten bands or move jars around during cooling.

Ways to use the tomatoes

Soups and stews: Add the tomatoes along with their juices to a simmering pot for a convenient tomato base.

Sauces: Drain them if a thicker starting point is useful, or include the liquid when the recipe needs extra moisture. Season the finished dish to taste.

Recipe notes & tips

• Blanch only a few tomatoes at a time so you can move them promptly into the ice bath.
• Use a funnel to keep tomato pieces away from the jar rims.
• Keep a clean bowl ready for the peeled tomatoes and discard the cores as you chop.
• Use a jar lifter when moving hot jars in or out of the canner.
• Check the pressure-canner instructions and current tested guidance before processing.

Variations

• Add herbs later: Stir fresh or dried herbs into a dish when you open a jar rather than changing the canning ingredients.
• Make a smooth sauce: Blend the tomatoes after opening a jar for a less chunky texture.
• Season at the table: Adjust herbs, spices and salt in the recipe you are making with the tomatoes.
• Use for soup: Add the diced tomatoes and their juices to a soup pot as its tomato base.

Common mistakes to avoid

• Cutting too deeply: Score only the skin so the tomatoes remain intact for peeling.
• Skipping the ice bath: Transfer each batch straight from the boiling water to the cold water to loosen the skins.
• Leaving tomato on the rim: Wipe the sealing surface with a damp paper towel before fitting the disc.
• Tilting hot jars: Lift them upright and set them down carefully after processing.
• Guessing the pressure adjustment: Check tested canning guidance for your altitude and equipment instead.

How to store

After cooling, label the jars and store them in a cool, dark cupboard, as the method directs. Follow current tested canning guidance for checking seals and storage; refrigerate after opening and use the contents promptly.

Frequently asked questions