Prepare your water-boiling canning pot. Fill your canning pot with water. Place your rack inside your canning pot. Place the jars and rings on top of the rack. Submerge the rack, jars, and rings, allowing the jars to completely fill with water. Ensure the water level is ultimately about one inch above your jars. Place your lid on your canning pot, and bring to a boil for 5 minutes. This step not only prepares your water-boiling canning pot or water bath, but it also sterilizes your jars. (Boiling water may harm the sealant on your lids, so you can sterilize your lids specifically by placing them in a saucepan in 180° water for 5 minute.)

Wash and blanch your tomatoes. Fill one large pot with water, and bring to a boil. As you’re waiting for the water to begin boiling, fill one of your large bowls with ice water. (Both the boiling water and ice water need to be ready at the same time.) Once the water is boiling, drop your tomatoes into the water for 30 seconds, one layer of tomatoes at a time. After 30 seconds, you ought to see the skin of your tomatoes begin to crack. Remove your tomatoes from the boiling water, and immediately submerge them in your ice water. Allow them to completely cool.

Core your tomatoes. Removing the core from your tomatoes will also give you a starting point from which to begin peeling.

Peel the skin from your tomatoes.

Briefly cook your tomatoes. Fill your second large pot with water. Allow your peeled tomatoes to simmer for 5 minutes.

Ready your sterilized jars. Remove your jars and rings from your canning pot, and remove your lids from your saucepan. They’re going to be hot to the touch, so use your jar lifter or anything you prefer that protects your hands. Remove any water that still remains in your jars.

Add lemon juice to your jars. If you are using pint-size jars, add one tablespoon of lemon juice. This is an incredibly important step because your lemon juice behaves as an acidifier and keeps your canned product safe over time. While it’s not essential to your final dish, you can add one teaspoon of sugar to offset the flavor of the lemon juice.

Pack your tomatoes. Take one tomato at a time out of the simmering water. Pack your tomatoes tightly into your jars, and ladel the water from your simmering pot over the tomatoes. Leave a small gap between your water and the top of the jar. (You can cut the tomatoes in half if you have enough space for ½ a tomato but not a whole.)

Tidy up. Wipe your jars clean, especially the rim of each jar, with a warm, damp towel.

Tighten. Add your lids and rings, and tighten almost all the way.

Seal. Submerge your tomato-filled jars in the water-boiling canning pot, and place the lid back onto your canning pot. Allow your jars to boil for 40 minutes. (If you are using quart-size jars, allow your jars to boil for 45-50 minutes.)

Cool. Remove your jars from the water bath, and set them on a towel or drying rack to cool.

Store and enjoy. Once cooled, ensure your jars have sealed properly. You can do this via two ways: one, listen for each jar to “pop,” an audible indication it has sealed or two, push the center of the lid to see if it pops up and down. If it doesn’t, it’s sealed! Tighten your ring the rest of the way, and add your sealed jar to your pantry. If the lid does pop up and down, it did not seal, but it’s okay! Simply put that jar in the refrigerator, and enjoy it within one month.