The Complete Guide to Canning Tomatoes

If your garden looks anything like mine right now, you probably have more tomatoes than you know what to do with. Vines are groaning beneath the weight of all those luscious fruits, and we don’t want any of them to go to waste! Fortunately, canning tomatoes is a great way to ensure that you capture every summer-sweet morsel.

Here’s how to get the job done.

What You’ll Need:

• Tomatoes
• A large stovetop pot (a canning pot with a removable rack is ideal)
• Additional pots or a dishwasher for sterilizing
• Glass canning jars with rings (various sizes)
• New canning jar lids
• Canning utensils (wide-mouthed funnel, tongs, lid lifter, bubble remover/headspace measure, jar lifter): I’d recommend getting a canning kit if you don’t already have one
• Sharp knife
• Ladle
• Slotted spoon
• Clean cloths/paper towels
• Large towel
• Measuring spoons
• Wooden spoons
• Bottled lemon juice
• Salt
• Seasonings (pepper, various herbs, and/or spices as desired)

Step 1: Sterilize Your Equipment

Boiling water is your best friend when you’re canning tomatoes. You’ll want to ensure that everything is well sterilized so there’s no chance that the contents will get contaminated.

Wash your canning jars with soapy water and rinse them well. Then, place them in the canning pot and cover them completely with water. Bring this up to a boil and simmer those jars for a good five to 10 minutes. While they’re being boiled, spread your, clean large towel over your kitchen table or countertop.

After you’ve sterilized the jars, turn the heat off and use your jar lifter to remove the jars one by one. Empty out excess water, then place the jars on the towel, open side upwards.

Then, fill a smaller pot with water and bring that to a boil. Place your jar lids and tightening bands into 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 upside down and use a sharp knife to cut an X into the bottom of each. Then set a large, clean bowl beside your stovetop.

Fill yet another pot with water and bring that to a boil. Place one tomato in the center of a slotted spoon, X side up, and immerse it into the water. Hold that there for 30 seconds, then drain it off and move it into 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 remove those and set them aside. You can either compost them later or dehydrate them to make tomato powder seasoning. Next, use your knife to core the skinned tomatoes, and cut them into quarters.

Step 3: Fill the Jars

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

Grab your measuring spoons and the bottled lemon juice. Add 2 tbsp of lemon juice to the bottom of each quart-sized jar, or 1 tbsp into each pint-sized jar.

Next, add salt: you’ll use 1 tsp for each quart jar, or 1/2 tsp 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 extra seasonings, if desired. I like to keep most of mine neutrally flavored so I can use them in pretty much any recipe, but additional flavorings can be lovely.

For example, you can toss in some fresh basil and oregano if you like Italian flavors. I like to use these tomatoes in dishes like Shakshoukaso I’ll can them with cumin, coriander, and a bit of harissa.

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

Step 4: Remove Air Bubbles

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

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

Move the bubble remover all around the jars’ inside circumference. If you see a lot of bubbles being released, then repeat this process several times. Then push down and around until you’re satisfied that there are no (or very few) bubbles left.

Ensure that you still only have about 1/2 an inch of headspace in the jars, and move on to the next step.

Step 5: Head ‘Em

Dip a paper towel or clean cloth into hot water, and wipe the tops of your jars clean. Ensure that there’s no tomato residue on the jars’ mouths.

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

Then, use that magnet lifter to pull out a tightening band, and adjust that into place over the lid. Tighten this by hand so it stays in place, but don’t tighten too firmly.

Step 5: Processing Time!

Use the jar lifter to move these filled jars into the canning pot, one by one. Leave enough space between them that they aren’t touching. Feel free to wedge some cloth between them if you’re afraid that they’ll move around.

Ensure that the jars are covered by at least 1 inch of water, and then bring the water to a boil. Process these for 90 minutes. Then use your jar lifter to remove them from the pot. Place these hot jars onto the towel-covered surface, and allow them to cool.

You’ll know that the jars are sealed properly when you hear a loud “pop”. The lids will pull downwards when the seal is secure, leaving the centers concave.

If they don’t pop, or if the lids are still bouncy in the center, then you have a seal failure. You can either redo the process with the jars that failed or just keep them in the fridge and consume them within a week or so.

Just make sure to check that all the jars are sealed well before you store them. Furthermore, inspect them for any kind of mold or discoloration before cracking them open. The last thing you want is to end up with botulism! When in doubt, throw it out.

Other Options for Canning Tomatoes

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

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

Similarly, you aren’t limited to canning tomatoes whole: you can also prepare them as salsa, sauce, paste, or even juice.

Your best bet is to get yourself a canning book such as the Ball Blue Book of Preserving. Try out some different recipes and canning methods, and determine which you like the best. Then you can fill your entire pantry with delicious, home-preserved goodness and enjoy summery tomato-liciousness all year round.