How to Can Tomato Sauce

How to Can Tomato Sauce recipe, tomato sauce in a glass jar

The Spruce / Julia Estrada

  • Total: 2 hrs
  • Prep: 30 mins
  • Cook: 90 mins
  • Servings: 32 servings
Nutritional Guidelines (per serving)
21 Calories
0g Fat
5g Carbs
1g Protein
See Full Nutritional Guidelines Hide Full Nutritional Guidelines
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Nutrition Facts
Servings: 32
Amount per serving
Calories 21
% Daily Value*
Total Fat 0g 0%
Saturated Fat 0g 0%
Cholesterol 0mg 0%
Sodium 78mg 3%
Total Carbohydrate 5g 2%
Dietary Fiber 1g 5%
Protein 1g
Calcium 12mg 1%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
(Nutrition information is calculated using an ingredient database and should be considered an estimate.)

When you end up with a surplus of fresh tomatoes, one of the best things to make is canned tomato sauce. This basic canned (or jarred) tomato sauce contains just tomatoes, salt, and lemon juice, which assures a proper acidic environment for canning. Feel free to add any additional flavors (such as herbs) later when you are ready to use the sauce. Fleshier plum tomatoes, like Roma or globe-shaped Early Girl tomatoes, are great to use since they have less juice, requiring less time to cook down the sauce.

You will need 4 pint-size jars with sealable lids for canning; the lids and jars need to be sterilized, which can be done by boiling in a large pot for 10 minutes. Let dry before filling. Canned tomato sauce will remain good for up to a year, stored in a cool, dark place.

Ingredients

  • 8 pounds supremely ripe red tomatoes (a bit overripe doesn't hurt either)
  • 1 teaspoon sea salt
  • 1/4 cup jarred or bottled lemon juice (divided)

Steps to Make It

  1. Gather the ingredients.

    How to Can Tomato Sauce recipe ingredients, tomatoes, sea salt, lemon juice

    The Spruce / Julia Estrada

  2. Rinse the tomatoes and pat them dry. Bring a pot of water to a boil. Cut a small "x" in the bottom of each tomato and blanch them in the boiling water for about 30 seconds.

    tomatoes in a large pot of water

    The Spruce / Julia Estrada

  3. Use a slotted spoon to transfer the tomatoes to an ice bath to cool.

    tomatoes in an ice bath, in a metal bowl

    The Spruce / Julia Estrada

  4. Lift tomatoes out of the ice bath, slip off their skins, cut the tomatoes in half, and squeeze out the seeds.

    peel and seed tomatoes

    The Spruce / Julia Estrada

  5. Put the peeled and seeded tomatoes in a pot with the salt and bring just to a boil. Reduce the heat to maintain a steady but gentle simmer and cook, stirring now and again, until the mixture is reduced by about a third, about 45 minutes. If at any point the mixture starts sticking to the pot, lower the heat and stir more often.

    tomatoes cooking in a large pot

    The Spruce / Julia Estrada

  6. Meanwhile, bring a canning kettle full of water to a boil. To sterilize the jars and lids, place them in the pot and boil for at least 10 minutes.

    canning kettle full of water to a boil and sterilize the jars and lids

    The Spruce / Julia Estrada

  7. Then, using a jar lifter, transfer them to a cooling rack to let them dry. (They will remain somewhat hot after they are dry.)

    sterilized glass jars ad lids on a metal cooling rack

    The Spruce / Julia Estrada

  8. Put 1 tablespoon of the lemon juice in each of the four jars.

    lemon juice in glass jars

    The Spruce / Julia Estrada

  9. Transfer the hot tomato sauce to the hot jars (a wide-mouth canning funnel works well), leaving about 1/2-inch of space at the top.

    tomato sauce and lemon juice in glass jars

    The Spruce / Julia Estrada

  10. Screw on the lids, put the jars in a canning rack, and lower them into the boiling water in the canning kettle. Process (boil) for 40 minutes. There needs to be at least an inch of water covering the jars, so keep an eye on the water level, adding more boiling water if needed.

    glass jars with tomato sauce in a large pot, canning process

    The Spruce / Julia Estrada

  11. Remove the jars and let them cool. Store them in a cool, dark place (a cupboard or pantry works great) until you're ready to use some tomato sauce.

    glass jars of tomato sauce, jarred tomato sauce

    The Spruce / Julia Estrada

Alternative Way to Peel and Seed Tomatoes

Instead of blanching and then peeling and seeding the tomatoes, you can remove the skin and seeds using a food mill. Roughly chop the whole tomatoes and run them through the food mill; the skin and seeds will remain on top while the tomato pulp accumulates below.

Why Add the Lemon Juice?

Safe canning requires that the food has a guaranteed level of acidity, as the acid is what preserves the food and wards off bacteria (such as the type that causes botulism). Some of today's tomato varieties have low levels of acid, requiring an additional ingredient. In this recipe, the addition of bottled or fresh lemon juice lowers the pH level, creating the proper acidic environment for canning. Acidic ingredients, or foods with an added acid, are safe to can using a water bath while all other foods need to be pressure canned.

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