Learning how to can diced tomatoes is an easy canning project for beginners. Follow these step-by-step simple instructions, with just 2 ingredients, and you have preserved garden fresh tomatoes to use in a variety of recipes.

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Canning diced tomatoes are the perfect beginner project for those who want to start to learn to water bath can. The basic ingredient is ripe tomatoes and you have the option of using lemon juice or citric acid as the additional acid.
There is no vinegar in this recipe so you have to add a bit of acid to make the tomatoes reach an acid level so they will be shelf-stable. I would use a jar of these diced tomatoes for a super mild Velveeta sausage dip.
Jump to:
- 🍅 Ingredients for canning diced tomatoes:
- What supplies are needed for canning tomatoes?
- 🔪 Canning Recipes for Diced Tomatoes
- 📷 Guide to water bath canning jar of diced tomatoes
- Recipes using Canned Diced Tomatoes
- 📝 Frequently asked questions, answers and tips:
- Best tomatoes for canning?
- 👩🍳 Chef Tip
- Canning Diced Tomaotes
- 👩🏻🍳 Sarah Mock
- Comments
🍅 Ingredients for canning diced tomatoes:
- Tomatoes - ripe, fresh, washed, blemish-free.
- Citric acid - powdered (or bottled lemon juice) - will help balance the acid level in the tomatoes. Bottled lemon juice is preferred over fresh as it has been tested at the manufacturer. Citric acid is also an option if it is available to you. I keep a 5 lb bag in my cabinet but I do a lot with citric acid in my cooking.
What supplies are needed for canning tomatoes?
- Pint canning jars - I use Ball canning jars, wide mouth or regular mouth will both work for this project. Quart jars can be used if you want to can quarts of diced tomatoes.
- Canning lids - new lids need to used for each canning project. Be sure to use a wide mouth lid on a wide mouth jar and a regular lid on a regular jar.
- Canning Rings - check to be sure the corresponding rings are not bent, free from rust, and clean. Rings can be reused whereas lids are a one time use for canning.
- Large Stock Pot - I use the deepest pot I have. The pot should be deep enough that water covers the jars by 2" when the jars are submerged in the water.
- Jar lifter, jar funnel, headspace tool - Ball as a canning utensil set that has all three of these in them but they can be purchased separately. PLEASE get a jar lifter. I worked with years without one and it was not safe. Don't be like me.
- A second pan of simmering water & an ice bath - I have a pan of simmering water ready for when I blanch and peel the skins off of the tomatoes. This is the easiest way to skin a tomato. The bowl of ice water is so you can plunge the tomatoes into, stopping the cooking process and allowing the skin to easily peel away.
- Towels, cutting board, colander, knife, bowl - The towels are for placing your hot jars on to protect your counter surface and the other items will help in the tomato chopping process.
🔪 Canning Recipes for Diced Tomatoes
- Was, core and remove the stem of ripe tomatoes.
- Heat a large pot of water over high heat to a simmer. And fill a large bowl with ice and water for an ice bath.
- While the water heats, use a sharp pairing knife to slice an X in the skin of each tomato.
- Drop the tomato in the simmering water for 30 seconds to one minute.
- Once the skin blisters and starts to split, remove it from the water and plunge it into ice-cold water bath to stop the blanching.
- Remove the tomato skin, the tomato seeds and dice the tomatoes.
📷 Guide to water bath canning jar of diced tomatoes
- Wash, sterilize, and heat the canning jars. Check out my canning 101 post if you need more step-by-step instructions.
- Heat the water in the larges stockpot. I also turn on my exhaust fan to help eliminate some of the heat and humidity that comes with canning. Keep the jars in hot water while you prepare the tomatoes for canning.
- Wash and inspect the tomatoes - I grow tomatoes in the garden and when I bring them into the house they have dirt on them. Thoroughly wash tomatoes and remove any bad spots or blemishes on them. Remove the stem and core, if desired.
- Remove the skin of the tomato - Use a sharp knife to slice and X or score the skin of the tomato, drop the tomato into the simmering water for 30 seconds to a minute.
- After the skin of the tomato has further cracked and started to separate from the tomato flesh, remove hot tomatoes from the water with a slotted spoon and plunge the tomato into the ice water bath, stopping the blanching process and allowing the skin to easily pull back.
- Peel the tomatoes - remove them from the ice water bath and remove the skin from the tomato. They should slip right off. If you get stubborn skin, dunk the tomato back in the water for an additional 15-30 seconds and then back into the ice water.
- Dice the tomatoes - I do a small to medium dice on my tomatoes as that is what I would normally pick up if I were to buy a can of diced tomatoes at the grocery store. Leave the seeds in the tomato and try and capture as much of the tomato juice in a bowl as you can.
- Remove a jar from the canner - place the empty, hot jar on your work surface, protected with a towel.
- Add lemon juice to the jar - if using lemon juice, add ½ teaspoon of lemon juice to the quart jar OR ¼ teaspoon of citric acid to the quart jar if using citric acid. See notes if you are canning larger portions.
- Place the funnel on the jar and fill the jar with your diced tomatoes. Be sure to get a balance of juice and tomatoes in the jar.
- Check for air - use your bubble remover tool or a nonreactive scraper, such as bamboo or silicone, to press the tomatoes and remove the air. Check for ½" headspace with the tool, wipe the rim, add a new lid and finger tighten a ring on the jar.
- Place the mason jar back in the simmering water - Use the jar lifter to place the filled jar back in the hot water bath.
- Repeat until all jars have been filled and returned to the hot water bath canner.
- Set the timer for 40 minutes for pints and 45 minutes for quarts.
- After processing is complete, carefully remove the jars from the canner with a jar lifter, and place them on a towel or rack and let the jars cool for 12 to 24 hours.
- Check the lids for flex. If the jars do not flex the lids have sealed correctly. If there is flex on the lid when it is pressed the lid has not sealed.
Recipes using Canned Diced Tomatoes
📝 Frequently asked questions, answers and tips:
Best tomatoes for canning?
The best tomatoes for canning should be firm, fresh, free of blemishes, and not affected by frost or pests. I am a fan of using a tomato with fewer seeds as I find they are meatier and less watery. I like to can a Roma tomato, San Marzano tomato or paste tomato
When you first pull the jars from the canner you will notice that the diced tomatoes have floated to the top of the jar and the water has sunk to the bottom. This is normal. Once the jars have fully cooled, just shake the tomatoes to reincorporate the water back into the tomatoes.
Separation can occur when using the cold pack method that I call for in this canning technique. The action of the enzymes in the cut room temperature tomatoes will begin to break down the pectin in the tomatoes. This breakdown results in a yellow red-tinted liquid that can appear in either the top or bottom of the jar. : Iowa State University
To prevent the separations, a hot pack method should be used.
👩🍳 Chef Tip
- Process in a boiling water bath : Pints: 35 minutes Quarts: 45 minutes
- Store unsealed jars in the refrigerator and use up within 7-10 days.
- Do not add thickeners or milk to tomatoes or tomato products before processing. Add the ingredients to make stewed tomatoes or tomato soup when you are ready to serve them. from the Penn State Extension
- Do not add extra peppers, onions, garlic etc. for flavor in this recipe, it will make the acid level be out of balance.
- Tomatoes may also be processed in a pressure canner.
- Tomato products with added vegetables or meat require pressure canning.
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Canning Diced Tomaotes
There is more to a recipe than just the recipe card. Frequently Asked Questions within the blog post that you may find helpful. Simply scroll back up to read them!
Ingredients
- 4 pounds Roma Tomatoes
- 2 teaspoons Lemon Juice (divided)
Instructions
- Wash, sterilize, and heat the canning jars. Check out my canning 101 post if you need more step by step instructions.
- Heat the water in the larges stockpot. I also turn on my exhaust fan to help eliminate some of the heat and humidity that comes with canning. Keep the jars in hot water while you prepare the tomatoes for canning.
- Wash and inspect the tomatoes - I grow tomatoes in the garden and when I bring them into the house they have dirt on them. Thoroughly wash your tomatoes and remove any bad spots or blemishes on them. Remove the stem and core, if desired.4 pounds Roma Tomatoes
- Remove the skin of the tomato - Use a sharp knife to slice and X or score the skin of the tomato, drop the tomato into the simmering water for 30 seconds to a minute.
- After the skin of the tomato has further cracked and started to separate from the tomato flesh, remove it from the water with a slotted spoon and plunge the tomato into the ice water bath, stopping the blanching process and allowing the skin to easily pull back.
- Once all the tomatoes have been blanched - remove them from the ice water bath and remove the skin from the tomato. They should slip right off. If you get a stubborn skin, dunk the tomato back in the water for an additional 15-30 seconds and then back into the ice water.
- Dice the tomatoes - I do a small to medium dice on my tomatoes as that is what I would normally pick up if I were to buy a can of diced tomatoes at the grocery store. Leave the seeds in the tomato and try and capture as much of the tomato juice in a bowl as you can.
- Remove a jar from the canner - place the empty, hot jar on your work surface, protected with a towel.
- Add lemon juice to the jar - if using lemon juice, add ½ teaspoon of lemon juice to the quart jar OR ¼ teaspoon of citric acid to the quart jar if using citric acid. See notes if you are canning larger portions.2 teaspoons Lemon Juice
- Place the funnel on the jar and fill the jar with your diced tomatoes. Be sure to get a balance of juice and tomatoes in the jar.
- Check for air - use your bubble remover tool or a nonreactive scraper, such as bamboo or silicone, to press the tomatoes and remove the air. Check for ½" headspace with the tool, wipe the rim, add a new lid and finger tighten a ring on the jar.
- Place the jar back in the simmering water - Use the jar lifter to place the filled jar back in the hot water bath.
- Repeat until all jars have been filled and returned to the hot water bath canner.
- Set the timer for 40 minutes for pints and 45 minutes for quarts.
- After processing is complete, carefully remove the jars from the canner with a jar lifter, and place them on a towel or rack to cool for 12 to 24 hours.
- Check the lids for flex. If the jars do not flex the lids have sealed correctly. If there is flex on the lid when it is pressed the lid has not sealed.
Notes
Tips for canning diced tomatoes:
- Process in a boiling water bath : Pints: 35 minutes Quarts: 45 minutes
- Store unsealed jars in the refrigerator and use up within 7-10 days.
- Do not add thickeners or milk to tomatoes or tomato products before processing. Add the ingredients to make stewed tomatoes or tomato soup when you are ready to serve them. from the Penn State Extension
- Do not add extra peppers, onions, garlic etc. for flavor in this recipe, it will make the acid level be out of balance.
- Tomatoes may also be processed in a pressure canner.
- Tomato products with added vegetables or meat require pressure canning.
Nutrition
Nutrition Disclosure
Nutritional facts are estimates and are provided as a courtesy to the reader. Please utilize your own brand nutritional values to double check against our estimates. Nutritional values are calculated via a third party. Changing ingredients, amounts or cooking technique will alter the estimated nutritional calculations.
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👩🏻🍳 Sarah Mock
CEO/Owner/Founder/Culinary Blogger
Sarah Mock is a classically trained Chef and graduate of Johnson & Wales University. A culinary blogger for 14 years Sarah helps the home cook prepare her recipes with professional results.
Terry
So...first blanching, then cooking again for a hot pack, then 40 minutes processing time. How do I keep the tomatoes from being so overcooked that they disintegrate when I open the jars?
Sarah Mock
I am not sure. I am not a pressure canner, canner. I will have to do some research on this one.
Sarah
What would the weight and time be in a pressure cooker?