Prepare a water bath canner and canning jars before beginning.

Wash tomatoes and remove skins by blanching the fruit in hot water. Transfer to a bowl of cold water when the skin begins to curl and remove the skins.

Core and halve the tomatoes, using your fingers and a small teaspoon to remove the seeds and pulp.

Dice the peeled, cored and seeded tomatoes into 1/2-inch to 1-inch strips or squares.

Prepare a hot water bath canner, jars, and 2-part lids for canning. If using a pressure canner, see below for processing times and PSI.

Add 2 tablespoons of bottled lemon juice OR 1/2 teaspoon citric acid to each quart jar. If using pint jars, add 1 tablespoon bottled lemon juice or 1/4 teaspoon citric acid to each jar.

Optionally, add up to 1 teaspoon of salt to each jar (if desired).

Place the diced tomatoes in a stock pot and cook over high heat for 5 minutes until heated through (don't add more liquid, the tomatoes will release their own juices as they cook). *For Crushed tomatoes, see notes.

Pack the hot tomatoes into the prepared jars, leaving 1/2-inch headspace. Apply 2-part lids and gently screw on the rings until fingertip tight.

Load the jars into a water bath canner and process for 45 minutes if using quart jars or 35 minutes if using pint jars. Theses times are for elevations lower than 1,001 feet — see note below for altitude adjustments.

When the canning time has finished, let the jars sit in the hot water for 5 minutes before removing them with a jar lifter.

Arrange the hot jars on a clean towel or canning rack, leaving at least 1-inch of space around the jars to allow for even air distribution.

Let the jars sit for 12 to 24 hours or until the contents reach room temperature.

Once the jars have cooled, check the seals and remove the rings. Store any unsealed jars in the fridge and use within a week.

Label and store canned diced tomatoes on the pantry shelf for 12 to 18 months.