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Heirloom tomato soup makes the most of colorful heirloom tomatoes in season, and canning these vibrant heirlooms allows you to preserve a rainbow of colors on your pantry shelf.

Heirloom Tomato Soup

This heirloom tomato soup recipe brings the bright, fresh flavors of summer straight to your pantry, perfect for canning and enjoying all year long. The beauty of heirloom tomatoes—whether red, yellow, orange, green, or even purple—is that they each contribute their own unique color and taste to the soup. If you’re looking for a vibrant, colorful addition to your pantry, heirlooms are the way to go!

You can mix and match heirloom varieties, but do keep in mind that mixing colors will typically result in a brownish-red soup. If you’re after jars filled with the bright hues of heirloom tomatoes, consider canning each color separately for a striking display of yellow, orange, or green in your pantry. It’s a simple way to preserve not only the taste but also the vibrant beauty of your harvest.

Heirloom Tomatoes for Canning

Ingredients for Heirloom Tomato Soup

This canning recipe is adapted from The Ball Blue Book Guide to Preserving, which calls it “Vine-Fresh Tomato Soup.” That recipe encourages you to use any color of tomato, including green or yellow heirlooms. The problem is, it also includes canned tomato paste which is always red.

I’ve adapted the recipe to use a bit more tomatoes, and a slightly longer cook time. That means you don’t have to add red tomato paste to get the right texture and yield, and you can keep those vibrant heirloom colors.

To make about 4 quarts (or 8 pints) of heirloom tomato soup for canning, you’ll need:

14 to 16 lbs heirloom tomatoes (42 to 48 medium-sized tomatoes, or less with extra large heirlooms)
1 sweet bell pepper (choose color based on your tomato color)
1 medium onion (white onion will give great taste and neutral color)
2 garlic cloves, minced
2 Tbsp. olive oil
1 Tbsp. sugar
1 Tbsp. salt
1 tsp. ground black pepper
Citric acid or bottled lemon juice (for safe canning)

The lemon juice or citric acid is added directly to each canning jar rather than into the soup pot. This ensures that each jar gets enough added acidity for safe waterbath canning (and this can be extra helpful if your yield is slightly off, due to natural variation in heirloom tomatoes).

For pint jars, you’ll need 1/4 teaspoon of citric acid or 1 tablespoon of lemon juice. For quart jars, use 1/2 teaspoon of citric acid or 2 tablespoons of lemon juice.

Heirloom Tomatoes for Canning

Notes on Mixing Tomato Colors

While it’s tempting to mix the colors of heirloom tomatoes for a more complex flavor profile, note that combining varieties like yellow, red, and green will likely result in a soup with a brownish-red color. If you want your soup to have distinct bright colors, it’s best to make separate batches using tomatoes of the same color. This way, you’ll get lovely jars of yellow, orange, or green soup, perfect for gifting or showcasing on your pantry shelves.

I think it’s extra fun to make a soup with a big batch of green zebra tomatoes, which have amazing flavor and a bright green color.

Green Zebra Tomato Soup

How to Make Heirloom Tomato Soup

Start by preparing the tomatoes. Wash, core, and quarter them, then set them aside. If you prefer a smooth soup, you’ll want to remove the skins and seeds later, which is easy to do with a food mill.

Next, chop up the vegetables. Dice the bell pepper after removing the stem, seeds, and membranes, and peel and chop the onion into small pieces.

Heat the olive oil in a large stock pot or Dutch oven. Once the oil is hot, add the onion and minced garlic, cooking them until the onions become translucent, but not browned.

Add the prepared tomatoes, bell pepper, tomato paste (or extra tomatoes if you prefer), sugar, salt, and pepper to the pot. Bring everything to a boil, then reduce the heat to a simmer. Let it simmer, uncovered, for about 30 minutes, giving the tomatoes time to soften and the mixture to thicken slightly.

Once the soup has cooked down, it’s time to strain it. Use a food mill or food strainer to remove the skins and seeds, which will leave you with a smooth, velvety texture.

After straining, return the soup to the pot and simmer it for another 25 to 40 minutes to thicken it further. The total cooktime here can vary because all heirlooms contain a different amount of water. You’re aiming for a tomato soup thickness, which pours easily off a spoon in a single stream (but isn’t watery). Stop before the mixture gets as thick as tomato sauce.

Heirloom Tomato Soup

Canning Heirloom Tomato Soup

Before you begin filling your jars, make sure you prepare them by adding the necessary amount of citric acid or lemon juice directly into each jar.

For pint jars, you’ll need 1/4 teaspoon of citric acid or 1 tablespoon of lemon juice. For quart jars, use 1/2 teaspoon of citric acid or 2 tablespoons of lemon juice.

Once your jars are ready, ladle the hot soup into each one, leaving about an inch of headspace at the top.

Now it’s time to seal the jars. Apply the two-piece canning lids, tightening the rings until they’re “finger tight.”

Process the jars in a water bath canner for 40 minutes, whether you’re using pint or quart jars. Make sure to adjust times for altitude if you’re above 1,000 feet in elevation.

When the processing time is up, carefully remove the jars from the canner and place them on a clean towel to cool on the counter for 12 to 24 hours.

After they’ve cooled, check the seals—any jars that didn’t seal properly should be refrigerated and used immediately, or you can reprocess them if needed.

Once properly sealed, the jars can be stored in a cool, dark pantry for up to 12 to 18 months. After opening, refrigerate and consume within a week or so.