Skip to Main navigation Skip to Left navigation Skip to Main content Skip to Footer

University of Minnesota Extension

Extension is almost done building a new website! Please take a sneak peek or read about our redesign process.

Extension > Food > Food Safety > Preserving and Preparing > Tomatoes and Salsa > Canning crushed tomatoes using boiling water canner

Print Icon Email Icon Share Icon

Tomatoes and Salsa

Canning crushed tomatoes using a boiling water canner

Suzanne Driessen

canner and tomatoes and jars

Clean: Food safety starts here!

Wash hands for 20 seconds

Clean and sanitize sink and counter tops

Canning directions:

  1. Prepare jars

    • Inspect jars for chips and cracks.
    • Wash jars in hot soapy water, rinse well.
    • Fill the canner half full with clean warm water.
    • Center the canner over the burner and preheat the water to 140°F for raw-packed foods and to 180° F for hot-packed foods. Use a food thermometer to monitor temperature.
    • Put jars into canner so they fill with water.
    • Prepare tomatoes while preheating jars.
  2. Wash tomatoes

    • Tomatoes — disease free, firm
    • Wash tomatoes under running water (10 degrees warmer than tomatoes). Scrub gently with produce brush.
    • You will need approximately 3 pounds of tomatoes per quart jar. (4 medium round tomatoes = 1 pound)
  3. Blanch, peel, core and prep tomatoes

    • Bring a pot of water to boil.
    • Put tomatoes in boiling water for 30 to 60 seconds or until skins split.
    • Dip tomatoes in a pot of COLD ice water.
    • Remove skins with knife.
    • Remove cores. Trim off any bruised or discolored portions and quarter.
    • Place in bowl or container.
  4. Heat tomatoes

    • Heat one-sixth of the quarters quickly in a large pot, crushing them with a wooden mallet or spoon as they are added to the pot to release juice so no water needs to be added. Continue heating the tomatoes, stirring to prevent burning.
    • Once the tomatoes are boiling, gradually add remaining quartered tomatoes, stirring constantly. These remaining tomatoes do not need to be crushed. They will soften with heating and stirring.
    • Continue until all tomatoes are added. Then boil gently 5 minutes.
  5. Prepare jars

    • Use jar lifter to remove jars from canner.
    • Add 2 Tablespoon bottled lemon juice to each quart jar. (1 Tablespoon/pint) (OR use citric acid ¼ teaspoon/pint or ½ teaspoon/quart).
    • Add 1 teaspoon canning salt to each quart, (½ tsp./pint). (optional).
  6. Prepare lids

    • According to research done by the Jarden Home Brands’ quality assurance team, pre heating metal canning lids is not necessary. To prep lids wash with warm, soapy water and keep at room temperature.
  7. Fill jars

    • Ladle tomatoes into hot jars using a funnel (jar filler).
    • Insert a plastic utensil to remove trapped air bubbles. (Don't use metal as it can scratch the glass increasing risk for breakage.)
    • Re-adjust headspace if needed by adding extra tomatoes.
    • Wipe top of the jar rim with a damp clean paper towel.
    • Apply screw band, finger tight. Do NOT over tighten.
  8. Load the canner

    • Place filled jars in canner one at a time using a jar lifter. Make sure the jar lifter is securely positioned below the neck of the jar (below the screw band of the lid). Keep the jar upright at all times. Tilting the jar could cause food to spill into the sealing area of the lid.
    • Add more boiling water, if needed, so the water level is at least one inch above the jar tops. For process times over 30 minutes, the water level should be 2 inches above the jars.
    • Turn the heat setting to its highest position, cover the canner with its lid and heat until the water boils vigorously.
    • Set timer. Process quarts for 50 minutes and pints for 40 minutes.
    • Lower heat setting if needed. Be sure to maintain a gentle complete boil for the entire process time.
    • Add more boiling water during the process, if needed, to keep the water level 1-2 inches above the jar tops.
    • If the water stops boiling at any time during the process, turn the heat on its highest setting, bring the water back to a vigorous boil, and begin the timing of the process over from the beginning (using the total original process time).
  9. Unload canner

    • When timer rings, turn off heat and remove cover.
    • Wait 5 minutes before removing jars to prevent ‘spill overs' and ensure good seals.
    • Using a jar lifter, remove the jars one at a time, being careful not to tilt the jars.
    • Place jars directly onto a towel or cake cooling rack, leaving at least one inch of space between the jars during cooling.
  10. Cooling and storage

    • Let the jars sit undisturbed while they cool, from 12 to 24 hours. Do not tighten ring bands on the lids or push down on the center of the flat metal lid until the jar is completely cooled.
    • Remove ring bands from sealed jars. Test seal. Press the center of the lid. It is sealed if there is no clicking sound.
    • Put any unsealed jars in the refrigerator and use first.
    • Wipe jars and lids with a wet cloth.
    • Label with name of contents and date.
    • Store in a cool, dark, dry place for up to 1 year.


Canning Lids 101, Ball, retrieved from March 2, 2015

Revised by Suzanne Driessen 2017

  • © Regents of the University of Minnesota. All rights reserved.
  • The University of Minnesota is an equal opportunity educator and employer. Privacy