Canning Tomato Paste (Homemade Tomato Paste Recipe)

Canning tomato paste turns a mountain of ripe Roma tomatoes into small jars of concentrated flavor that take up almost no room on the pantry shelf. It’s the same process as tomato sauce, just carried much further, and a single tablespoon does more work in a winter soup than a whole cup of thinner sauce ever could.

Every year we grow literally hundreds of pounds of tomatoes, and no matter how many we eat fresh in August, there’s always a wave of them that needs to go into jars before the frost comes. I’ll can whole tomatoes when I’m short on time, because they go up fast, but whole tomatoes eat an enormous amount of shelf space for what you get back out of them.

Canning tomato sauce is a step better, since a food mill handles the peeling and seeding for you, but you’re still storing an awful lot of water in every jar. Paste is where that math finally tips in your favor. You’re canning flavor and nutrition with most of the water cooked out, which means the jar is small, the shelf stays open for other things, and you’re not simmering off a pot of liquid later just to get a sauce thick enough to cling to pasta.

The tradeoff is time. Paste asks for a long, slow afternoon at the stove and a fair bit of stirring, and this recipe comes straight from the National Center for Home Food Preservation, which is the only source I’ll use for a tomato product this thick. If you’re brand new to putting up tomatoes, it’s worth reading through canning diced or crushed tomatoes first, since that post walks through the prep work in more detail and gives you an easier project to cut your teeth on.

Ingredients for Canning Tomato Paste

The ingredient list is short, but don’t skip the citric acid! It’s required for safe canning. The seasoning is to personal taste, and you can skip that if you like and make plain tomato paste, but the tomatoes and citric acid are required to get the job done.

• Roma or paste-type tomatoes: These have dense, meaty flesh and very few seeds, which means less water to cook off and a smoother finished paste. Slicing tomatoes and heirlooms will work, but they carry so much more juice that you’ll add hours to the reduction and end up with a smaller yield.
• Citric acid: This is the safety ingredient, and it isn’t optional. Tomatoes sit close to neutral on the pH scale, so acid has to be added before they can be safely processed in a boiling water canner. Buy food grade citric acid rather than the descaling kind sold for appliances.
• Canning or pickling salt: Salt is here for flavor and does nothing for safety, so you can leave it out if you’re watching sodium. Use canning and pickling salt rather than table salt, since the anti-caking agents in table salt will cloud the paste.
• Bay leaves (optional): Two whole leaves go in during the second cook and come back out before the jars are filled. They add a savory background note that you’d miss if it weren’t there.
• Garlic (optional): One whole peeled clove, added and removed the same way as the bay. It’s a single clove for the entire batch, not a whole bulb, and it perfumes the paste rather than making it taste garlicky.

The Romas sold in grocery stores are almost always the Heinz variety, bred by the ketchup company for processing rather than flavor. If that’s what you can get, use it without worrying, because the long cook and the canning process both pull out whatever sweetness the fruit has in it.

If you’re growing your own, though, the heirloom paste varieties are worth the seed order. The three I keep coming back to are Amish Paste, Hogs Heart and Opalka, all of which hold up well here in our short zone 4 season.

There’s more on choosing varieties in my guide to the best tomatoes for canning, and if you’re starting from scratch in spring, growing tomatoes from seed opens up varieties you’ll never find as transplants.

How to Make Tomato Paste

Making paste happens in two distinct cooks with a trip through the food mill in between. The first cook takes the raw tomatoes down by half and softens them enough to separate cleanly from their skins and seeds.

The second cook takes that sieved pulp down by half again, which puts you at roughly a quarter of your original volume and turns sauce into paste.

Preparing the Tomatoes

Wash the tomatoes well, pulling stems as you go and trimming out anything bruised or discolored. Don’t bother peeling or seeding at this stage if you own a food mill or a fine sieve, since the mill will do that job far faster than your hands can. If you don’t have either one, you can peel and seed by hand before cooking instead, and my post on peeling tomatoes covers the fastest way to get through a big pile of them.

Tomato juice separates from the pulp within seconds of a tomato being cut, which is why the order of operations matters here. Working with about a pound of tomatoes at a time, quarter them and drop them straight into a hot saucepan, crushing them with a potato masher over high heat until they come to a boil.

Keep cutting and adding and mashing until every tomato is in the pot, stirring often so nothing catches on the bottom. Resist the temptation to cut everything up ahead of time, because the juices will already have separated by the time the pot gets hot.

Separated juice is perfectly safe to eat, and it’s nearly impossible to avoid if you’re peeling by hand, so don’t panic if it happens. The hot crush method simply gives you a smoother, more cohesive paste at the end. Once everything is in the pot, drop the heat to low and simmer uncovered for about an hour, until the volume has come down by half.

Now run the cooked tomatoes through a food mill or press them through a fine sieve to take out the skins and seeds. I use the food mill attachment on my KitchenAid, which makes short work of a big batch, though a hand crank food mill or a chinois will get you to the same place with a little more elbow grease. If you peeled and seeded by hand at the start, you can skip this step entirely and keep cooking.

Weston makes a really nice stainless steel tomato strainer, and that’s worth investing in if you’re putting up a lot of tomatoes either as paste or as sauce.

Whatever you do, don’t reach for a blender or food processor to speed this up. The blades whip air into the tomatoes, and incorporated air is exactly what you don’t want in a product you’re about to can. It also purees the skins back into the paste instead of removing them, which isn’t recommended for canned tomato products.

Cooking Down the Paste

Return the sieved tomatoes to the pot and stir in the citric acid until it’s completely dissolved and evenly distributed. Then add the salt, the bay leaves, and the garlic clove if you’re using them. Getting the acid in at this stage rather than at the end is a safety requirement, and I’ve explained why in the section just below.

Cook uncovered over medium heat until the paste is thick enough to round up on a spoon, which takes roughly two and a half hours. Stir frequently the whole time, and almost constantly toward the end, because the thicker it gets, the faster it will scorch. Be careful of spatter as well, since thick boiling paste throws hot droplets a surprising distance.

Acidifying Tomato Paste for Canning

Adding citric acid is the single step in this recipe you cannot skip. A lot of people assume tomatoes are highly acidic, but they’re actually borderline when it comes to canning, and modern varieties have drifted further that way over the decades. Without added acid, tomato products aren’t acidic enough to be safely processed in a boiling water canner.

With most tomato products I tell people to put the acid directly into the empty jars before filling them, which is how I handle it when I’m canning sauce or whole tomatoes. Paste is the exception, and it’s an important one. The NCHFP is specific that the citric acid has to go into the sieved tomatoes before they’re cooked down, because paste is far too thick to distribute acid evenly once it’s finished. Stirring it into a full jar of finished paste simply won’t work, and the ratio of acid to pounds of tomatoes has to stay consistent.

Readers ask about lemon juice constantly, so it’s worth being clear. Most tomato canning recipes give you the choice of bottled lemon juice or citric acid, and in general one teaspoon of citric acid is the equivalent of a quarter cup of bottled lemon juice. This particular recipe, though, was tested with citric acid only, and the published version gives no lemon juice option at all. I’d stick with citric acid here.

White vinegar is technically an acidifier for some tomato products, but I’d steer well clear of it for paste. It will leave you with something that tastes distinctly pickled, and after five hours at the stove that’s a hard thing to discover.

Canning Tomato Paste

Have your water bath canner, eight or nine half pint jars, and two-part lids ready before the paste finishes, since you want to fill the jars while everything is still hot. If this is your first canning project, my beginner’s guide to water bath canning covers the whole process start to finish, and common beginner canning mistakes is worth a read too. There’s also a full rundown of what’s worth owning in my guide to canning supplies.

Two things about jars. Paste is dense, which makes it slow for heat to work its way to the center of a jar, so this recipe has only been tested in half pints. Don’t move up to pints or quarts. You can safely go smaller, and quarter pint jars processed for the same length of time work beautifully if you only use a spoonful at a time.

Fish out the bay leaves and the garlic clove, then ladle the hot paste into your hot jars, leaving 1/2 inch of headspace. A canning funnel with headspace markings saves a lot of mess with something this thick. The jars need to be hot going in to prevent thermal shock and cracking.

Run a nonmetallic spatula, plastic knife, or wooden chopstick down between the paste and the jar wall to release trapped air, which takes some persistence in a product this thick. Wipe the rims with a clean damp cloth, center the lids, and screw the bands down until they’re fingertip tight, meaning you stop as soon as the band stops turning easily. Don’t crank them down, and don’t touch them again after processing.

Process the jars in a boiling water canner for 45 minutes, adjusting for your altitude using the chart below. When the time is up, turn off the heat and let the jars sit in the canner another 5 minutes before lifting them out with a jar lifter. That short rest helps prevent siphoning.

Set the jars on a rack or a folded towel with an inch of space around each one, away from cold surfaces and drafts. Give them 12 to 24 hours to come to room temperature before you check the seals.

Press gently on the center of each lid, and if it flexes down and springs back the jar hasn’t sealed and belongs in the fridge. If it doesn’t move at all, you’re set. Take the rings off, label the jars with the contents and the date, and put them away.

Storage Options

Canning isn’t the only way to keep a batch of paste, and if you’d rather skip the canner entirely the freezer works well for this.

• Refrigerator ~ An opened jar keeps about a week to ten days in the fridge. Half a pint is a lot of paste for a small household, so I usually freeze whatever I won’t get through quickly.
• Freezer ~ Spoon the finished paste into ice cube trays, freeze solid, then pop the cubes into a freezer bag. Each cube runs right around a tablespoon, which is exactly the amount most recipes call for. Frozen paste holds its quality for about 6 months.
• Canned ~ Sealed jars stored somewhere cool, dark and dry hold their quality for 12 to 18 months. Refrigerate after opening.

Ways to Use Tomato Paste

A spoonful of paste bloomed in hot oil at the start of a braise, a chili, or a pot of soup builds a savory backbone that’s hard to get any other way. I stir it into bean dishes, into pan sauces for meat, into stews that need more body, and into the base of nearly every long simmered thing we eat between November and April.

It’s also what turns a thin pot of sauce into something that actually clings to noodles, which is worth knowing if your heirloom tomatoes cooked down watery. In tested recipes, like thickened tomato salsa, you can add it to salsa as well.

Once the paste is put up, there’s usually still tomatoes coming in, and it’s worth spreading the harvest across a few different methods so you’re not stuck with nine cases of the same thing.

Tomato jam is a good use for a smaller batch, dehydrating tomatoes takes almost no active attention, and freeze drying tomatoes is worth considering if you have the equipment. My full list of tomato canning recipes has the rest if you’re after more ideas.

If you’re running a big tomato year and your kitchen is getting unbearable, setting up an outdoor canning kitchen changed our whole August routine for the better. There’s also a broader index of canning recipes covering everything else that comes out of the garden.

Canning Tomato Paste FAQs

Ways to Preserve Tomatoes

Canning Tomato Sauce (Plain or Seasoned)

Dehydrating Tomatoes

Tomato Jam

Tomato Canning Recipes

Canning Tomatoes (Whole or Halves)

Canning Diced or Crushed Tomatoes

Best Tomatoes for Canning