Step 1: Wash and core the tomatoes, then chop them into large chunks. In a large heavy-bottomed pot, combine the tomatoes, onions, celery, and garlic.
Step 2: Simmer the mixture over medium heat for about 30-40 minutes until all the vegetables are soft and the tomatoes have broken down completely.
Step 3: Use an immersion blender to puree the mixture until smooth, or run it through a food mill to remove skins and seeds for a silkier texture.
Step 4: Return the pureed soup to the pot and add salt, pepper, and sugar. Simmer for another 15-20 minutes to reduce slightly and concentrate the flavors.
Step 5: Prepare your water-bath canner and sterilize 7 pint-sized jars. Place 1 tablespoon of bottled lemon juice into the bottom of each hot, sterilized jar.
Step 6: Ladle the hot tomato soup into the jars, leaving 1/2 inch of headspace. Remove air bubbles and wipe the rims clean.
Step 7: Apply lids and bands until finger-tight. Process in a boiling water-bath canner for 40 minutes (adjusting for altitude).
Step 8: Remove jars and let them cool undisturbed for 24 hours. Check seals before storing in a cool, dark place.