The Complete Guide to Canning Tomatoes

If your garden looks a bit like mine right now, you probably have more tomatoes than you know what to do with. The vines are groaning under the weight of all that luscious fruit, and we don’t want any of them to go to waste! Luckily, canning tomatoes is a great way to make sure you capture every sweet bite of summer.

Here’s how to do the job.


What you will need:

  • Tomatoes
  • A large pot on the stove (a canning pot with a removable rack is ideal)
  • Additional pans or dishwashers for sterilization
  • Glass jars with rings (various sizes)
  • New canning jar lids
  • Canning utensils (wide mouth funnel, tongs, lid lifter, bubble eliminator/headspace measure, jar lifter): I recommend getting a canning kit if you don’t have one don’t already have one
  • Sharp knife
  • Suspicious
  • Split spoon
  • Clean rags/paper towels
  • large towel
  • measuring spoons
  • wooden spoons
  • Bottled lemon juice
  • Salt
  • Seasonings (pepper, various herbs and/or spices of your choice)

Step 1: Sterilize your equipment

Boiling water is your best friend when canning tomatoes. You’ll want to make sure everything is properly sterilized so there’s no chance of the contents being contaminated.

Wash your jars with soapy water and rinse them well. Then, place them in the pot and cover them completely with water. Bring to a boil and simmer these jars for a good five to 10 minutes. While they’re boiling, lay out your large, clean towel on your kitchen table or counter.

After sterilizing the jars, turn off the heat and use your jar lifter to remove the jars one by one. Drain the excess water, then place the jars on the towel, open side up.

Next, fill a smaller saucepan with water and bring it to a boil. Place your jar lids and clamp bands in this pot and boil them for about five minutes. Then turn the heat down to its lowest setting and leave those items in there until you’re ready to use them.

You can also run the jars and rings through the dishwasher on the hottest cycle instead of sterilizing them in water.

Step 2: Prepare your tomatoes

Rinse your tomatoes well and remove the stems. Then flip them over and use a sharp knife to cut an X at the bottom of each. Next, place a large, clean bowl next to your stove.

Fill another pot with water and bring it to a boil. Place a tomato in the center of a slotted spoon, X side up, and drop it into the water. Hold it for 30 seconds, then strain it and move it to the clean bowl.

Repeat this process until all of your tomatoes have been blanched.

The skins will just slip off the tomatoes at this point, so peel them off and set them aside. You can either compost them later or dehydrate them to make a tomato powder seasoning. Then use your knife to hollow out the peeled tomatoes and cut them into quarters.

Step 3: Fill the jars

You can either use the wide mouth funnel for this or just use your hands.

Grab your measuring spoons and bottled lemon juice. Add 2 tablespoons of lemon juice to the bottom of each quart jar or 1 tablespoon to each quart jar.

Next, add salt: you’ll use 1 teaspoon for each quart-sized jar, or 1/2 teaspoon for each pint-sized jar. If you’re on a low-sodium diet, feel free to skip the salt.

At this point you can also add additional seasonings, if desired. I like to keep most of my flavors neutral so I can use them in just about any recipe, but additional flavors can be nice.

For example, you can add fresh basil and oregano if you like Italian flavors. I like to use these tomatoes in dishes like Shakshoukaso I’m going to box them with cumin, coriander and a little harissa.

Transfer the cut tomato pieces to your sterilized jars. Use the handle of a wooden spoon to press down on the tomatoes to release their juice. Keep adding tomatoes (and juice) until the jars have 1/2 inch of headspace.

Step 4: Remove air bubbles

Don’t skip this step, as it is one of the most important to do when canning tomatoes.

Take your debubbler and use it to move the contents of the jars. This should release any bubbles that may be trapped inside. If you don’t remove them, they can cause leaks, as well as potential fermentation.

Move the bubble extractor all the way around the inside circumference of the jars. If you see a lot of bubbles releasing, repeat this process several times. Then push down until you are satisfied that there are no (or very few) bubbles left.

Make sure you still only have about 1/2 inch of free space in the jars and move on to the next step.

Step 5: Cap ‘Em

Dip a clean paper towel or cloth in hot water and wipe the tops of your jars. Make sure there is no tomato residue on the mouth of the jars.

Then use your bottle opener (the long stick with the magnet on the end) to lift a lid out of the hot water. Place it on the jar, rubber side down, and press it into place.

Then use this magnetic lifter to remove a clamp band and adjust it in place on the lid. Hand-tighten it so it stays in place, but don’t over-tighten.

Step 5: Processing time!

Use the jar lifter to move these filled jars into the canning jar, one by one. Leave enough space between them so they don’t touch each other. Don’t hesitate to wedge a little fabric between them if you are afraid that they will move.

Make sure the jars are covered with at least 1 inch of water, then bring the water to a boil. Treat them for 90 minutes. Then use your jar lifter to remove them from the jar. Place these hot jars on the surface covered with a towel and let them cool.

You’ll know the jars are properly sealed when you hear a loud “pop”. Covers pull down when seam is secure, leaving concave centers.

If they don’t jump or the lids still bounce in the center, you have a gasket failure. You can either repeat the process with the jars that failed, or simply store them in the refrigerator and consume them in about a week.

Just be sure to check that all jars are properly sealed before storing. Also, inspect them for any kind of mold or discoloration before you open them. The last thing you want is to end up with botulism! If in doubt, throw it out.

Other options for canning tomatoes

Everyone has their own proven method for canning tomatoes. This is the technique I was taught, but there are additional options as well.

For example, some people like to pre-cook (and season) their tomatoes, then pack them in the jars while they’re still hot. If you use this method, the processing time in the boiling water bath is reduced to 40 minutes from 90.

Likewise, you’re not limited to canning whole tomatoes: you can also prepare them as a salsa, sauce, paste, or even juice.

Your best bet is to get a canning book such as the Ball Blue Book of Preserving. Try different recipes and canning methods and see which ones you like best. Then you can stock your entire pantry with delicious home-preserved goodies and enjoy the summer sweetness of tomatoes all year round.

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