Heirloom Tomato Sauce

Heirloom tomato sauce captures the color and flavor of heritage varieties in a way that a standard red sauce just can’t. A single batch can come out deep purple, bright green, or golden orange depending on what you grew, with a flavor all its own, so the jars on your shelf taste like the specific tomatoes from your garden rather than a generic puree.

This recipe follows the NCHFP standard tomato sauce method, which means it’s tested and approved for water bath canning. It works with any tomato variety, so it’s the same safe process you’d use for paste tomatoes, just applied to the heirlooms you want to show off. If you’re after more ideas for the harvest, the full collection of tomato canning recipes has options for every kind of tomato you might be growing.

The one thing that changes with heirlooms is yield. They tend to carry far more water and larger seed cavities than meaty paste tomatoes like Romas, so you’ll need roughly 1.5 to 2 times the weight to land the same amount of finished sauce.

If you’d like to preserve that heirloom character in another form, there’s also heirloom tomato soup for a ready-to-eat option, a seasoned roasted marinara sauce if you want herbs and garlic cooked in, or canned tomato juice when you have a glut to work through.

Choosing Heirloom Tomatoes

Any heirloom variety will make safe sauce provided it’s properly acidified, so the choice really comes down to the color and flavor you want in the jar. Purple and black types like Black Krim and Cherokee Purple give you that deep brooding color, green varieties like Green Zebra stay startlingly green, and yellow or orange types like Brandywine Yellow, Kellogg’s Breakfast, and Lemon Boy land somewhere between gold and amber. Sticking to a single variety per batch keeps the color clean and lets one tomato’s character carry the whole jar.

You can absolutely mix varieties for a more layered flavor, though the colors tend to blend toward a muddy red once they’re combined, so you lose the single-variety drama. Whatever you choose, look for fully ripe, unblemished fruit, and cut away any bruised or soft spots before they go in the pot. Since heirlooms are watery, having a lot on hand matters more than with paste tomatoes, so pick when several plants are producing heavily and you can fill a batch in one go.

Ingredients for Heirloom Tomato Sauce

Heirloom tomato sauce keeps the ingredient list short, with just tomatoes and an acidifier doing the work. The tomatoes carry all the flavor here, so this is the place to use the varieties that excite you most.

• Heirloom Tomatoes: Any variety works, from purple-black types to green, yellow, or orange. Plan on roughly 16 to 24 pounds for about 4 pints of sauce, which is around 1.5 to 2 times what you’d need with paste tomatoes. The exact amount depends on how watery your variety runs and how thick you cook the sauce down. For a single-variety batch, use one kind throughout; for more complexity, blend a few and accept a more muted color.
• Bottled Lemon Juice or Citric Acid: Required for safe canning, and not optional. Add 1 tablespoon bottled lemon juice OR 1/4 teaspoon citric acid per pint (double both for quarts). Use bottled lemon juice rather than fresh, since bottled has a consistent acidity that fresh does not. The acid is the safety control for this recipe and cannot be reduced, no matter how tart the tomatoes taste.
• Salt (optional): Salt is for flavor only and does nothing for safety. Add 1/2 teaspoon per pint or 1 teaspoon per quart if you like, or leave it out entirely with no effect on the process.

This is a plain, unseasoned sauce by design. You can add herbs, garlic, and other flavorings when you open a jar to use it, which gives you far more flexibility than committing to a seasoning during canning.

If you’d rather have the seasoning cooked in from the start, the roasted marinara sauce recipe is built for that.

How to Make Heirloom Tomato Sauce

Making this sauce comes down to three stages: peeling the tomatoes, milling them into a smooth puree, and simmering that puree down until it reaches the thickness you want. None of it is difficult, but the simmering takes patience with heirlooms because of all the water you’re cooking off.

It helps to get your canner heating and your jars washed before you start, so everything is ready to go once the sauce is done. From there, work through the steps below in order, and don’t rush the reduction at the end.

Blanch and Peel the Tomatoes

Wash the tomatoes and remove any stems or damaged portions. Working in batches, dip them in boiling water for 30 to 60 seconds, just until the skins start to split, then transfer them right away to a bowl of ice water (or cold well water) to stop the cooking.

Once the tomatoes are cool enough to handle, the skins should slip off easily. Pull off the skins, cut out the cores, and chop the tomatoes into quarters or large chunks so they break down quickly in the next step.

Make the Puree

Place the peeled, cored tomatoes in a large pot and bring them to a boil. Boil uncovered for about 20 minutes, stirring now and then to keep them from sticking, until the tomatoes have fully broken down into a loose, soupy mixture.

Run the softened tomatoes through a food mill to remove the seeds and any stray bits of skin, which leaves you with a smooth puree ready for simmering. If you don’t have a food mill, you can blend the tomatoes and push them through a fine mesh sieve instead, though you’ll lose a little more volume that way.

Simmer to Thicken

Return the puree to a large, wide pot, since a wider surface lets the moisture evaporate faster. Bring it to a boil, then lower the heat to a steady simmer and cook uncovered, stirring frequently so the bottom doesn’t scorch. For a thin sauce, reduce the volume by about a third; for a thicker sauce, keep going until it’s reduced by about half.

With heirloom tomatoes this stage takes longer than it would with paste tomatoes, simply because there’s more water to drive off. Plan on 45 minutes to an hour or more depending on how thick you want the finished sauce, and trust the consistency in the pot over the clock.

Canning Heirloom Tomato Sauce

Once the sauce has reached the consistency you want, it’s time to get it into jars. If you’d rather not can the whole batch, the sauce keeps in the refrigerator for up to a week, or you can freeze it in freezer-safe containers for up to 6 months.

To can, prepare your water bath canner, jars, lids, and bands, keeping the jars hot until you’re ready to fill them. Add the acidifier to each hot jar first, then salt if you’re using it. Ladle the hot sauce into the jars through a canning funnel, leaving 1/4 inch headspace.

Slide a bubble remover or chopstick around the inside of each jar to release trapped air, adjust the headspace if needed, then wipe the rims with a clean, damp cloth, center the lids, and apply the bands fingertip tight.

Process in a boiling water bath canner, making sure the jars are covered by at least 1 to 2 inches of water. Process pints for 35 minutes and quarts for 40 minutes at elevations up to 1,000 feet, adjusting for altitude (see the table below).

When the time is up, turn off the heat and let the jars rest in the canner for 5 minutes before lifting them out onto a towel-lined counter. Leave them undisturbed for 12 to 24 hours, then check the seals, remove the bands, and store in a cool, dark place.

Tips for Success

A food mill is the piece of equipment that makes this recipe smooth. It pulls out the seeds and skins while leaving you with the pulp, which matters more with heirlooms than with paste tomatoes because heirlooms carry so many more seeds. Run the cooked tomatoes through while they’re still hot, and pass the pulp through a second time if you want an especially smooth texture.

The other thing that makes a difference is the pot you reduce in. A wide, shallow pan exposes more surface area and cooks the sauce down noticeably faster than a tall, narrow stockpot, which can save you a good half hour with watery varieties.

Stir often as the sauce thickens, since a reducing tomato sauce scorches easily once most of the water is gone, and a scorched bottom will flavor the whole batch.

Ways to Use Heirloom Tomato Sauce

Plain heirloom tomato sauce is a blank canvas that lets the color and flavor of your tomatoes lead. Because it goes into the jar unseasoned, you can take it in any direction once you open it, which is part of why a plain sauce earns its shelf space.

• Quick marinara: Sauté garlic in olive oil, add a jar of sauce, and season with salt, basil, and oregano for a fast pasta sauce that shows off your tomato variety.
• Pizza base: Spread it on homemade pizza as-is or lightly seasoned. The unusual color of a variety like Black Krim or Green Zebra makes for a striking pie.
• Soup starter: Use it as the base for tomato soup, adding cream, broth, or other vegetables as you like.
• Shakshuka: Warm the sauce in a skillet, crack eggs into it, and cook until the eggs are just set.
• Braising liquid: Use it as a base for braising chicken, meatballs, or vegetables.
• Curry base: Swap it in for canned tomatoes in curry recipes, adding spices as the recipe directs.

However you use it, the color tends to be the conversation starter, so a sauce that came off the shelf looking purple or green is worth saving for dishes where it’ll actually show.

Keep a few jars of your most unusual varieties back for those.

A few common questions come up when people make this sauce for the first time, so here are the ones I hear most.

Heirloom Tomato Sauce FAQs

For more ways to put up the tomato harvest, browse the rest of the collection below.

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Classic Vegetable Soup

Southern Chow Chow (Traditional Green Tomato Relish)

Old-Fashioned Green Tomato Jam

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