How to Can Diced Tomatoes With the Water Bath Method

Roma tomatoes are the ideal choice for canning, and a water bath canning method is preferred over pressure canning. Follow these steps for canning diced tomatoes with a hot water bath canner.

1. 1. Gather your supplies. You'll need a sharp knife, cutting board, slotted spoon, colander, a large bowl filled with ice water, citric acid or bottled lemon juice, wide-mouth canning jars (ideally pint jars or quart jars), two-piece metal jar lids (flat metal discs and rings), measuring cups, a canning funnel, a jar lifter, a large stockpot, and a wire rack that can fit in your stockpot.
2. 2. Wash tomatoes thoroughly. Thoroughly rinse your fresh tomatoes under cold water. Use your knife to cut away the stem and any blemishes.
3. 3. Blanch the tomatoes. Blanching tomatoes for sixty seconds in boiling water helps the skin peel away from the flesh. Bring a large pot of water to a boil then place the tomatoes in the water for sixty seconds. Remove the tomatoes with a slotted spoon and immediately place them in a bowl of ice water to stop them from cooking.
4. 4. Peel, seed, and dice the tomatoes. Remove the tomatoes from the ice water and gently peel away the tomato skins. Squeeze the peeled tomatoes to remove the seeds, then place the tomatoes on a cutting board and dice them to your desired size.
5. 5. Sterilize the canning jars. Place clean jars in a water bath canner or other deep, large pot with a wire rack placed at the bottom. Cover the jars with hot tap water and simmer over medium heat for ten minutes. Keep them in hot simmering water until they are ready to fill. Place the lids in a heat-safe bowl and pour hot water from the sterilizing pot over the lids. Once ready, remove one sterilized jar from the water and place it on a clean kitchen towel.
6. 6. Prepare the tomatoes using the hot pack method. Place the diced tomatoes in a stockpot with boiling water and boil them for five minutes. Then remove the tomatoes with a slotted spoon.
7. 7. Add citric acid to the jars. Adding citric acid to the jars ensures that the tomatoes maintain a safe pH level. Add two tablespoons of bottled lemon juice or half of a teaspoon of citric acid per quart of tomatoes. If you’re using pint jars, add one tablespoon of bottled lemon juice or a quarter teaspoon of citric acid.
8. 8. Pour the hot tomatoes into the jar using a ladle and funnel. No additional canning liquid is required. As the tomatoes process, they will release their own tomato juices. Leave a half-inch headspace at the top of the jar.
9. 9. Release any trapped air bubbles. Poke the contents with a clean chopstick or wooden skewer or tap the jar on the counter to release air bubbles.
10. 10. Wipe the rims of the jars with a clean, damp cloth. Secure the canning lids until they’re fingertip tight, or secure but still able to be twisted off with your hands.
    
11. 11. Place the filled jars in the canner. As you fill and close each jar, use a jar lifter to place it gently in the stockpot filled halfway with water. Space the jars evenly apart and be sure that the jars do not touch each other. You may need to remove some water as you add jars to the pot.
12. 12. Cover the top of the jars with water. When all the jars have been placed inside the pot, cover them with one inch of water.
13. 13. Heat the canner. Place the stockpot filled with water and jars over high heat, cover it with a lid, and bring the water to a full rolling boil.
14. 14. Boil the jars. Boil the jars according to the processing time specified by your canning recipe. The total time it takes to process your jars varies from recipe to recipe.
15. 15. Carefully remove the jars. When the recommended time has passed, remove the jars from the boiling water bath, place them on a towel-lined counter, and let them cool to room temperature. You should hear the hot jars ping as soon as they’re removed from the pot. The sound is from the seals being formed. When processed correctly, the center of the lids will become concave as the vacuum seal takes hold, creating an airtight seal.
16. 16. Allow the jars to cool. Once the jars are cooled, test the seals by pressing the center of the jar lids. If the lid pops up and down, the jar isn’t sealed. Jars that don’t seal can be stored in the refrigerator and used within three days or reprocessed within twenty-four hours.
17. 17. Store the jars of tomatoes. Store your canned diced tomatoes in a cool, dry, dark place for up to one year.

Most home canning recipes call for hot packing, or pre-cooking, diced or crushed tomatoes. Hot packing is preferred over raw packing for its tendency to yield better color and flavor. To hot pack diced tomatoes, boil the diced tomatoes for five minutes before adding them to the canning jars.

Become a better chef with the MasterClass Annual Membership. Gain access to exclusive video lessons taught by the world’s best, including Alice Waters, Gabriela Cámara, Niki Nakayama, Chef Thomas Keller, Gordon Ramsay, Yotam Ottolenghi, Dominique Ansel, and more.