It seems like every recipe I make in the winter calls for diced tomatoes.
Unfortunately, the versions I can find at the store don’t taste great.
Now that I know how to can diced tomatoes, I can preserve the goodness of summer all winter long.
This recipe can scale up and down. That means you can pick your tomatoes and can the day’s harvest.
Big days mean a bigger yield!
Beginner-Friendly Guide to Making & Water Bath Canning Diced Tomatoes
Diced tomatoes are among the easiest tomato products to can in a water bath, and you don’t need much to get started.
Equipment Needed
- Stainless steel pan
- Paring knife
- Potato masher
- Water canner
- Pint jars
- Lids
- Rings
- Saucepan
- Lid lifter
- Jar lifter
- Canning funnel
- Timer
Ingredients
- Tomatoes (14 pounds for a full batch of nine pints)
- 1 tablespoon lemon juice per jar
- ½ teaspoon salt per jar (optional)
Step 1: Select Your Tomatoes
Choose tomatoes that are both ripe and firm. That means they’ll be bright red and slightly soft when you press on them. However, they shouldn’t be so ripe that they seem to melt under your fingertips.
In the summertime, you’ll likely have plenty of tomatoes that are perfect for canning. Note that you’ll need big tomatoes (like these). Cherry tomatoes can’t be used in this manner.
In the winter months, you may need to buy tomatoes from farmstands or grocery stores instead. That’s totally fine (as long as the tomatoes are ripe).
Step 2: Clean Your Tomatoes
All tomatoes have bacteria and soil on them. Run every tomato under warm water and use your fingers to remove any debris.
When your tomatoes are clean, use your fingertips to remove any stems and leaves from the top of your tomatoes.
Then, use a sharp knife to remove the tomato’s core. Cut straight down (like you’re carving a pumpkin) and remove the stem and the hard inner bit.
Step 3: Blanch Your Tomatoes
Since we’re not removing skins with a food mill for this project, we must blanch tomatoes and peel away the skins.
Some home canners consider skin removal optional. I do not, and neither do organizations like the Oregon State University Extension Service.
Skinning tomatoes ensures that they don’t have a high bacterial load. And trusted recipes (like those from extension services) are designed and tested with skinned tomatoes.
Leaving the skin on could change the acidity and make your products unsafe. Don’t do it.
(And I’ll explain more in Step 8).
Thankfully, skinning takes literally minutes. Blanching is the first step.
Working in small batches, place your tomatoes in boiling water for about a minute. You’ll see the skins start to crack.
Step 4: Cool Your Tomatoes
Place your blanched tomatoes in a bath of very cold water. I use ice to make sure it’s as cold as it can be. Leave the tomatoes for about a minute to allow the skins to loosen.
Step 5: Remove the Skins
Pull your tomatoes from the bath and rub them between your fingers. The skin will come off in big sheets with no tools or cutting required. Toss that skin into the compost heap.
Photo caption: Skinned tomatoes are ready to go.
Step 6: Prepare Your Jars
All good canning projects start with sparkling clean jars that have no cracks or chips. I wash all of my jars in very hot water with soap and rinse them well.
Next, I put all of my jars in my canner and fill it with water. Over medium heat, I bring the jars to a simmer and leave them that way until it’s time to fill them.
Sterilizing your jars for a recipe with a processing time longer than 5 minutes isn’t technically required per the Utah State University Extension. However, heating your jars can ensure that you’re not bringing germs from one project to another.
Heat can also test the integrity of your jars. If they crack while empty, that’s less heartbreaking than cracks that form when the jars are full (and you lose the contents for good in the water bath).
Step 7: Prepare Your Lids and Rings
Lids should be activated with heat before you use them. Place your rings in a saucepan on a back burner under very low heat. They can rest until you need them.
Count out all of the rings you’ll need for your jars. I always seem to forget this step and have to scramble at the end of these projects.
Don’t be like me! Plan ahead.
Step 8: Chop Your Tomatoes
Since this recipe calls for diced tomatoes, use a very sharp knife to dice your tomatoes and prepare them for the canner.
Don’t worry about making your cuts too precise, as they’ll cook down in the canner.
Step 9: Cook Your Tomatoes
Place about 2 cups of tomatoes in a stainless steel pan and bring them to a boil. Use a potato masher to crush this small batch as it cooks for a few moments. The bottom of your pan will fill with juice.
Next, add the rest of your tomatoes to the pot and stir well. Don’t worry about crushing these new additions, as they’ll cook down and soften.
Bring the entire pot to a boil and simmer for about 5 minutes.
Step 10: Acidify Your Jars
Using your jar lifter, pull jars out of the canner. Add 1 tablespoon of lemon juice to the bottom of every jar you’re going to use.
Tomatoes are low in acid, and that means they’re not safe to can without a little help. Lemon juice can acidify the tomatoes, and the flavor of the lemons can perk up the tomatoes, too.
Since tomatoes are so low in acid, they’re not safe to can without added acidity. They’re also not safe to can on the fly without a recipe. Remember to follow directions carefully.
Step 11: Fill Your Jars
With your canning funnel, fill your jars with a combination of tomatoes and juice. Leave a half-inch of space at the top of the jar to allow the tomatoes to expand as they cook in the canner.
As you fill your jars, tiny pockets of air may develop between your tomatoes. That air could harbor bacteria, so it should be removed before processing.
Use a butter knife to push the tomatoes to the center and remove the trapped air.
If you’re using salt, add a half teaspoon to the top of every jar.
Step 12: Apply Lids and Rings
Wipe the top of every jar with a damp paper towel to remove debris that might keep the lids from sticking. With your lid lifter, pull the lids out of their warm bath and place them on the jars. Screw a lid on the jar until it’s finger-tight.
Step 13: Process Your Jars
Place every prepared jar in your canner and cover with an inch of boiling water. Since you’ve already warmed water in the canner to sterilize your jars, this should be an easy step.
Once your water is boiling, set your timer. Pint jars should boil in the canner with the lid on for 35 minutes. Adjust for your elevation as needed.
Step 14: Cool Your Jars
When your tomatoes are processed, remove the lid from the canner and turn off the heat. Leave the tomatoes in the canner for 5 minutes.
With your jar lifter, gently remove your tomatoes from the canner and place them on a cutting board or towel for 24 hours.
Step 15: Test and Label Your Jars
When your jars are cool, remove the ring and press on the lid. It should be fully stuck to the jar, and you shouldn’t hear it pop or click when you press on it.
Write today’s date and the contents of the jars on the lids. I put the bands back on my tomatoes to store them, but you can leave them off if you prefer.
How Long Do Canned Diced Tomatoes Last?
Per the USDA, home canned food should be eaten within about a year. At this point, properly canned food is considered safe for anyone to eat.
Before you crack the lid and start eating, check your tomatoes for damage. If the lids pop under your fingers or are no longer firmly attached, that jar’s contents aren’t safe to eat. Your tomatoes should also be red, clear, and free of problems like mold.
Ideas for Using Canned Diced Tomatoes
There are literally hundreds of ways to use diced tomatoes. These are a few of my favorites:
- Top scrambled eggs with diced tomatoes for a quick breakfast.
- Boil down for tomato sauce.
- Add to tomato paste for a chunkier sauce.
- Add to diced peppers for a tasty meat sauce or marinade.
- Add to canned beans for a quick chili.
- Top a baked potato with diced tomatoes for a delicious dinner side dish.
Equipment
- 1 Timer
Ingredients
- 14 lbs Ripe, Firm Tomatoes (about 10-15 medium-large tomatoes)
- 1 Tbsp Lemon juice per jar
- ½ tsp Salt per jar optional
Instructions
Prepare The Tomatoes
- Select Tomatoes: Use ripe, firm tomatoes. Avoid overly soft or unripe fruit.
- Clean Tomatoes: Wash thoroughly under warm water, removing dirt and stems. Core each tomato by cutting out the tough stem area.
Blanch and Peel
- Blanch Tomatoes: Place tomatoes in boiling water for about 1 minute until the skins begin to crack.
- Cool: Transfer blanched tomatoes into a bowl of ice water for 1 minute.
- Peel Skins: Rub the tomatoes gently; the skins will slide off easily. Discard skins.
Prepare Jars and Lids
- Sterilize Jars: Wash jars in warm, soapy water. Place them in the canner, cover with water, and simmer until ready to use.
- Warm Lids: Place lids in a saucepan of warm water on low heat.
Dice and Cook Tomatoes
- Dice Tomatoes: Use a sharp knife to chop peeled tomatoes into small pieces.
- Cook: Place 2 cups of diced tomatoes in a pan and bring to a boil. Mash with a potato masher to release juice. Add the rest of the diced tomatoes and simmer for 5 minutes.
Acidify Jars
- Add Lemon Juice: Remove jars from the canner using a jar lifter. Add 1 Tbsp lemon juice to each pint jar.
Fill and Seal Jars
- Fill Jars: Use a funnel to ladle hot tomatoes and juice into jars, leaving ½ inch of headspace.
- Remove Air Bubbles: Run a knife or bubble removal tool along the inside edges of the jar to release trapped air.
- Season: If desired, add ½ tsp salt to each jar.
- Clean Rims: Wipe the rims with a damp paper towel to ensure a clean seal.
- Apply Lids and Rings: Place lids on jars and screw rings until fingertip-tight.
Process in Water Bath
- Canning: Place jars in the canner, ensuring they’re covered with at least 1 inch of boiling water. Process pint jars for 35 minutes (adjust for altitude if necessary).
- Cool: Turn off heat, remove the lid, and let jars rest in the canner for 5 minutes. Remove jars and let cool on a towel for 24 hours.
Inspect and Store
- Check Seals: Press the center of each lid. If it doesn’t flex, the jar is sealed.
- Label and Store: Write the date and contents on each jar and store in a cool, dark place for up to 1 year.
Notes
- Top scrambled eggs or baked potatoes.
- Boil down for tomato sauce or soup.
