Step 1

Rinse the tomatoes and cut in half, or quarters for larger tomatoes.

Step 2

Add a strainer/colander to a large bowl.

Step 3

Wash and sanitize your jars. You’ll want to keep them warm to avoid having them crack when placed in the canner. You can fill them with hot water, or place them on a tray in the oven at 170F.

Step 4

Wash your lids with hot soapy water and place them in a clean bowl for now.

Step 5

Add the tomatoes to a pot of boiling water and parboil them until you see the skins start to come off one of the tomatoes (about 1-2 minutes).

Step 6

Use a slotted spoon and remove the tomatoes and place in the strainer.

Step 7

Run the tomatoes through a food mill to remove the seeds and skins.

Step 8

Transfer the tomato puree to a pot over low heat or a crockpot set to low. Keep warm until ready to can.

Step 9

Add 3 quarts of water to your pressure canner and put it on a burner set to high. Make sure there is a canning rack in the bottom of the canner.

Step 10

Add lemon juice or citric acid to your canning jars.Quarts: 2 tbsp lemon juice OR 1/2 tsp citric acid. Salt (optional) 1 tspPints: 1 tbsp lemon juice OR 1/4 tsp citric acid. Salt (optional) 1/2 tsp

Step 11

Place a funnel on a canning jar and ladle in the warm tomato puree, leaving 1 inch of headspace. Headspace is defined as the space between the top of the food and the top of the jar.

Step 12

Using a long utensil (I prefer a plastic chopstick), remove all the air bubbles from the jar.

Step 13

Use a wet clean rag and wipe the rim of the jars to make sure they are free of any food.

Step 14

Place a clean new lid on the jar. Add a ring, and tighten to fingertip tight.

Step 15

Using canning tongs, gently place the jars in the canner. Lock the lid. Soon, steam will start coming through the vent pipe.

Step 16

Allow the steam to pass through for about 10 minutes. Then put the pressure regulator on top. (see photos in post above to see this in action)

Step 17

Pretty soon, the air vent will pop up. That is a sign that you’re starting to build pressure inside the canner. Tomato soup need to be pressure canned at 11 pounds of pressure for 15 minutes for both pints and quarts. (see time chart in post for adjusted times for elevation and water bath canning).

Step 18

When the dial gauge reaches 11 pounds of pressure, reduce the burner temp to medium, and start your timer. The pressure must stay at 11 or (a little bit) above for the duration of the cooking time. You’ll likely need to adjust the temp on the burner a few times depending on your stove.

Step 19

When the time is up, remove the canner from the burner and allow it to sit until you hear a distinctive “click” of the air vent dropping. Remove the pressure regulator and carefully remove the lid (Pro tip: I always use oven mitts when I take the lid off because the steam is crazy hot).

Step 20

Let the jars sit for 5 minutes in the canner and then lift them out with canning tongs. Place on a towel where they can sit undisturbed for 12 hours.

Step 21

After a few hours, to check for sealing, gently press down in the middle of the lid. If the lid has no give, it’s sealed. If you can press the lid in and it pops a bit, your jars are not sealed.

Step 22

Complete steps 1-8 above.

Step 23

Fill your canner so that there will be 2 inches of water over the tallest jar that you are canning. Set it on a large burner set to high.

Step 24

Complete steps 10-14 above.

Step 25

When the water has reached a rolling boil, place the jars in the canner and place the lid on top. Process pints for 35 minutes or quarts for 40 minutes.

Step 26

When the time is up, remove the canner from the burner and let the jars sit for 5 minutes in the canner and then lift them out with canning tongs.

Step 27

Place on a towel where they can sit undisturbed for 12 hours.