Tips on how to make diced tomatoes

Once you’ve learned how to dice tomatoes, you can enjoy the delicious taste of garden fresh tomatoes any day of the year.

Every year, when our garden tomatoes start to ripen, we start preserving the harvest by canning and freezing various recipes.

We make salsa, pasta sauce, ketchup, tomato juice, tomato sauce and more from our tomatoes. But one of our favorite ways to preserve them is by making diced tomatoes and canning them in pint glasses.

Then, when a recipe calls for a can of diced tomatoes, I go to the pantry and pull out a pint glass made from the tomatoes in our garden.

Paste tomatoes are the preferred variety when canning diced tomatoes

But the best part is that this is a simple canning recipe that even a novice could master.

There are no complicated ingredients and no worries about balancing a mix of vegetables and worrying about the pH level is safe for canning.

While you need to follow these guidelines for safe canning, the actual recipe only calls for the following ingredients: Bottled tomatoes and lemon juice.

That’s it! And when you’re ready to dose the tomatoes, just put them in mason jars and process them in a hot water bath canning pot.

If you are new to canning we recommend this Canner water bath. We have one like this and have been using it for years and absolutely love it!

However, we also understand that not everyone has the canning equipment, but still wants to preserve their fresh tomatoes. In that case, be sure to read our article on freezing tomatoes.

Canning seasonOur favorite water bath canning machine that performs at its best every summer.

How to cook down diced tomatoes

* For full recipe instructions, see a printable recipe card at the end of this article.

* Makes about 9 pint glasses


  • 25 pounds of fresh tomato paste (about 1/2 bushel)
  • Lemon juice in bottles

What kind of tomatoes to use …..

The first step in canning diced tomatoes is to pick or buy your tomatoes. The best tomatoes for this recipe are pate tomatoes.

You can often find these varieties as Roma, Amish paste, or San Marzano. They are ideal to use because they have thicker walls, a thin shell, and an easy-to-remove seed core.

Although you can add a few slices of tomato to the mixture, it is recommended that you do not use more than 25% of this type of tomato when canning diced tomatoes.

The reason for this is that this variety of tomato produces a large amount of liquid and you end up getting a large amount of tomato juice instead of tomato pieces.

Low acidity tomatoes To do NOT Use low acid tomatoes in this canning recipe. And sadly, cherry tomatoes aren’t the best for canning tomato cubes either.

However, the most important guideline is to save your low acid tomatoes for other recipes and not to use them in this recipe.

Standard tomatoes, with their natural pH, can be safely bottled together with a little lemon juice. On the contrary, low acid tomatoes are not safe in the can without formally testing the pH of each batch.

Therefore, use this type of tomato for cutting and eating. Or you can do and freeze too Tomatosoup, chili or tomato sauce instead.


Now that you know which type of tomato to use, it’s time to get started! First fill 1/2 a large stock pot with water and bring it to a boil.

In another large bowl, add enough ice and water to fill the bowl 75%, then set aside.

Place the tomatoes in the boiling water in portions for one minute. Then remove the tomatoes with a slotted spoon or a spider web and place them in the ice water bath for 1-2 minutes.

Repeat the process until all of the tomatoes are blanched and frozen.

When the tomatoes are cool enough to touch, it’s time to peel the skin off. Make a small slit on both ends of the tomato.

Peel the tomatoesThe first step in canning diced tomatoes is to peel the skin off the tomatoes.

Then use a pairing knife to peel the skin off the tomato. It should come off easily. Repeat this process until all of the tomatoes have skin removed.

Then halve the tomato lengthways. Then remove the core of the kernels by scooping it out with a spoon or by squeezing the tomato over a large bowl.

Now is the time to cut the tomatoes into the pieces you want. I prefer to dice them into cubes that are about 1/2 inch tall. However, you can make them as small or large as you want.

When the tomatoes are ready, it’s time to get ready for the canning process.

The canning process

Start by sterilizing pint-sized mason jars. Most dishwashers have a sterilizer feature that you can use on your mason jars.

But you can also sterilize them yourself in the hot water bath canning pot. First, fill the mason jars with hot water and place them on the grid in the saucepan.

Then fill the pot with water until it reaches the top of the glasses. Bring the saucepan to a boil over medium heat.

sweet tomato jamTomatoes peeled and diced and begin to cook.

While the jars are sterilizing, place 1/6 of the diced tomatoes in a large stock pot and heat over medium heat. When the tomatoes start to heat up, mash them with a wooden spoon or potato masher to release their juice and stir frequently.

As soon as the mashed tomatoes come to a boil, add the remaining diced tomatoes and stir. Then bring the mixture back to the boil and continue cooking for 5 minutes.

Using a Glass lifter, take a pint glass and pour the hot water back into the double boiler. Then place the jar on a kitchen towel next to the boiling tomatoes.

Fill the glasses

Pour the hot diced tomatoes into the glass and add enough liquid to cover the tomatoes. Halfway through filling the jar, add the bottled lemon juice and then continue filling the jar, leaving 1/2 inch space for expansion.

Use a plastic knife to remove any air bubbles by sliding it down inside the jar. Then, wipe the edges of the jars and place a mason lid on top.

Add the tape and just finger tighten.

Put the jar back in the hot water bath jar and repeat the process until all jars are filled and put back into the jar. Before canning, make sure the water level is 1 to 2 inches above the top of the lids.

hot water bath

Bring the hot water bath canning pot back to the boil. Then set a kitchen timer to 35 minutes and adjust the cooking time according to the height as needed.

After the tomato cubes have been processed in the water bath canning pot for 35 minutes, switch off the burner. Carefully remove each glass with a glass lifter and place on a thick towel to cool.

Let the jars cool down for 24 hours. Then check the jars to see if they are properly closed by pressing the center of the lid. A closed glass lid does not move up and down.

If a jar isn’t closed properly, put it in the refrigerator and use it within 2 weeks. Store the sealed jars in a cool, dark place for up to a year.


Maria and Jim

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How to make diced tomatoes

  • 25th
    of fresh tomato pies
    about 1/2 bushel
  • bottled lemon juice
  1. Fill 1/2 of a large saucepan with water and bring to a boil. In another large bowl, add ice and water, set aside.

  2. Place the tomatoes in batches in boiling water for one minute, then remove and place in the ice-water bath until they are cool enough to handle. Peel the skin off the tomatoes and squeeze out the seeds and excess juice. Put aside. Repeat this process until all of the tomatoes have been peeled, pitted, and excess juice removed.

  3. Dice tomatoes into desired pieces.

  4. Prepare pint mason jars and a hot water bath canning pot.

  5. Put 1/6 of the tomatoes in a large stock pot and heat over medium heat. When they get warm, mash the tomatoes with a wooden spoon to release any remaining juice. Stir frequently.

  6. As soon as the mashed tomatoes come to a boil, add the remaining diced tomatoes and stir. Bring the mixture back to a boil. Cook for another 5 minutes.

  7. Pour hot diced tomatoes into warm, sterilized pint jars. Make sure you add enough liquid to cover the tomatoes, leaving 1/2 inch of space.

  8. Add 1 teaspoon of bottled lemon juice to each pint glass. Wipe the edges of the jars and put a warm lid on them. Add the ring finger-tight.

  9. Place the jars in a hot water bath jar and make sure the water level is 1 to 2 inches above the lids.

  10. Cook for 35 minutes and adjust the height as needed.

  11. Take out of the water bath and place on a thick cloth to cool down. Let stand for 24 hours and check that the jars are tight by pressing the center of the lid. A closed glass lid does not move up and down. Store in a cool, dark place.

Recipe courtesy of Old World Garden Farms

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