Let’s Get Sauced: How to Can Tomatoes at Home

Feeling saucy? You probably need some uber-flavorful home-canned tomatoes in your life (and in your marinara).

So gather your supplies, put on your dancing shoes, and strike a confident pose, because you can can tomatoes at home — here’s how.

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Gather your canning gear

This recipe makes 4 pints (or 2 quarts).

Equipment

• Pressure canner or water bath canner/large stockpot with canning rack and jar lifter
• 4 pint jars with lids
• Knife

Ingredients

• Ice
• Water
• 4 pounds Roma tomatoes
• Bottled lemon juice or citric acid
• Salt (optional)

Prep the tomatoes

1. Prepare an ice bath by filling a large bowl with ice and water. Bring a large pot of water to a boil.
2. Prepare tomatoes for boiling by scoring the skins (cutting an “X” into them), which will help you remove the skins more easily.
3. Add tomatoes to boiling water and cook until skins start to separate from edges (about 1 minute).
4. Remove tomatoes from boiling water and place them directly into ice bath.
5. Remove skins from tomatoes.

Assemble your jars

1. Add 1 tablespoon lemon juice to each pint jar* (or, if using citric acid, add 1/4 teaspoon to each pint jar). Add salt, if using (about 1/2 teaspoon per pint).
2. Fill each jar with tomatoes, being careful not to crush them. Each jar should have about 1/2 inch of headspace (empty space) below the lip of the jar. Add water if needed.

*If you want to use 2 quart jars, double the pint jar recipe for each quart jar.

Get canning!

Check your cans

Let the jars rest at room temperature for 24 hours, and then check the seals. The lids should be tightly sealed and slightly concave.

Improperly sealed jars should either be refrigerated and used within 1 or 2 days or be thrown away. Whatever you do, DON’T store them — they’re no good.

If the seal looks good, voila! You have canned tomatoes. They’ll keep in your pantry for about a year.

It’s super important to follow recipe instructions exactly when canning to minimize your risk of introducing contaminants to your canned food or creating an environment where pathogens can thrive.

To that end, there are two mondo-important considerations when it comes to food safety of canned tomatoes.

Acidity

There’s a reason you need bottled lemon juice (not fresh lemon juice) or citric acid — either one will add enough acidity to discourage bacterial growth. Although tomatoes themselves are acidic, they can’t quite do that job without some outside help.

No matter the canning recipe, it’s important that you never decrease the amount of acidic ingredients, so you can be sure your end product is acidic enough to prevent nasties from growing.

Proper seal

If the can doesn’t seal properly once you’ve gone through all the steps in a recipe, you need to use it immediately or throw it away. Cans that don’t seal can allow harmful pathogens to enter. The lid should be slightly concave (sunken in the center) after the canning process is complete.

You know what it’s like to roll up to the grocery store in January and grab a tomato only for it to be a flavorless, mealy disappointment.

That’s because tomatoes don’t usually grow in January. To arrive at your grocery store ripe, they have to be picked unripe somewhere more tropical and then allowed to ripen during shipping. And this just doesn’t allow their full tomatosity (yup, we just made that up) to shine through.

When canning tomatoes, you can buy locally grown (or use homegrown) tomatoes at peak freshness and suspend those flavors in time — so that when you’re craving some flavorful homemade tomato sauce in the wintertime, you’re covered.

Having home-canned tomatoes on hand also gives you total control over the ingredients in tomato-based sauces or salsas you make. You get to play around with your own recipes, removing or adding whatever ingredients you want.

This means you’ll be able to tailor your favorite homemade foods to your exact dietary needs and preferences — and it might even become your new fave hobby!

Can I use a steam canner, my oven, or a pressure cooker to can tomatoes?

You can use a steam canner for some acidic foods, but tomatoes aren’t one of them. Steam canners use the same processing time as water bath canners, but steam canners can process for a max of only 45 minutes because they quite literally run out of steam. Since our recipe needs 85 minutes, steam canning is a no-go.

You might also come across recipes that suggest canning food in the oven or a pressure cooker (or even in your dishwasher 🤢). Home canning experts advise against these methods because they’re straight-up dangerous. With any of these methods, your cans can easily explode (your pressure cooker might explode too), and canning in the oven or dishwasher is more likely to result in an unsafe end product.

What kinds of tomatoes can be canned?

The best tomatoes for canning are paste tomatoes or Roma tomatoes, both of which are sometimes called plum tomatoes.

They’re oval-shaped and fairly small, about the size of a plum — and they’re preferred for canning because they make the best sauces. These tomatoes are also low moisture, which keeps your canned tomatoes from becoming watery.

Heirloom tomatoes are another great choice, since these flavorful, gemstone-hued beauties are really only available to purchase during the summer — usually at your local farmers market. Canning them allows you to enjoy their flavors year-round.

But you can can any tomato using the same methods! Larger tomatoes might just need to be halved, quartered, or chopped so they’ll fit into the mouth of your canning jars.

Can I leave the skins on the tomatoes?

It’s up to you. Tomato skins are thicker and tougher than the flesh, and they contain flavonols that give them a slight bitter twang.

For canning, most people remove the skins so those little tougher bits don’t end up in their sauces. However, the same flavonols that give tomato skins their slightly bitter taste also provide some extra health benefits, sooo…

If you do decide to keep the skins on, you can skip the step of scoring the tomatoes before boiling them.

Do I have to worry about altitude?

Yes! As you get farther up into the sky, air gets thinner, which affects pressure and boiling points. This means you’ll need to change the pressure settings for pressure canners and adjust the processing time for water bath canners at higher altitudes.

For the recipe above, here’s how high altitude changes the processing time for each kind of canner.

Pressure canner

Depending on the type of pressure canner you’re using, here’s how you’ll need to adjust your settings:

Water bath canner

Tomato canning isn’t too bad if you’ve got the right tools — and it’s so nice to have the taste of summer tucked away to use any time.

BUT safety is a huge consideration. If you’re going to can tomatoes, you need the right tools, a good recipe that includes adequate acid, and a safe canning method (for tomatoes, that’s pressure canning or water bath canning).