While there is nothing like eating fresh tomatoes throughout the summer months, preserving some summer bounty for winter allows you to enjoy them all year round. Canning tomatoes is one way to preserve them for use in cooking during the winter. There is no need to purchase an expensive pressure or water bath canner. A water bath canner is no more than a large pot, and so you can use your largest soup or stock pot to preserve your tomatoes just as well.
Choose a metal pot that is at least 4 inches taller than your pint-size canning jars. Use a pot that has a tightly fitting lid. Place a round metal rack, such as a cake-cooling rack, in the bottom of the pot.
Wash your canning jars, lids and rings in hot, soapy water. Rinse the soap from the jars then keep them in warm water until you are ready to fill them.
Wash the tomatoes. Bring a pot of water to a boil, then submerge the washed tomatoes in the boiling water for one minute. Remove the tomatoes from the water and dip them into cold water, then slip off their skins.
Cut out the core from each skinned tomato. Leave the tomatoes whole or cut in half or quarters as desired.
Place the tomatoes in a pot and add just enough water to cover. Boil over medium heat for five minutes. While the tomatoes are boiling, fill the canning pot with water and bring it to a boil.
Pour the boiled tomatoes into the canning jars, leaving ½ inch of space between the tomatoes and the top of the jar. Add 1/2 tsp. canning salt and 1 tbsp. of lemon juice to each jar.
Wipe the rims of the jars dry with a clean cloth. Place lids on the jars, rubber sides down, then tightly screw on canning rings. Place the jars into the canning pot using the jar lifter, making sure the jars aren't touching each other or the sides of the pot. Add more water, if necessary, so the jars are covered with at least 2 inches of water, then bring the water back to a boil.
Place the lid on the pot once the water is boiling. Boil for 40 minutes at altitudes less than 1,000 feet, or 45 minutes at altitudes above 1,000 feet.
Lift the jars out of the boiling water with the jar lifter once the processing time is complete. Set them on a rack or counter covered in a towel to cool for 48 hours. The jar lids will make a pinging noise as they seal.
Check the jar lids after the cooling time is over to ensure they are now concave, signifying that they are sealed. Label the jars with the contents and canning date and store in a cool pantry until you are ready to use them.