How to Make Home Canned Condensed Tomato Soup
- 1). Melt 3 tbsp. butter in a frying pan over medium heat. Add celery and onions and cook until tender, about 10 minutes, stirring occasionally. Don't allow the onions to turn brown.
- 2). Simmer the tomatoes and water in a large stock pot over medium-low heat until the tomatoes are soft and the skins split, about 45 minutes. Stir the tomatoes occasionally so they don't burn.
- 3). Pour the onions, celery and tomatoes, including the liquid, into a blender or food processor and blend until smooth. Add salt and sugar to taste. Sweet tomatoes need less sugar, while acidic types need more to mellow the flavor. Blend the tomatoes in several batches if you have a small blender or food processor.
- 4). Strain the tomato mixture through a colander to remove any solids or tomato peels. The soup should have a smooth, velvety consistency.
- 5). Rinse and dry the stock pot. Melt the remaining 5 tbsp. butter in the pot over low heat, and whisk in the flour to make a roux, stirring constantly so it doesn't burn. Cook the roux for one minute. Add the tomato mixture and heat it slowly, stirring constantly to thicken. Keep the soup warm, while you prepare the jars for canning.
- 6). Fill the boiling-water canner with water and heat on high. Wash six pint-size jars in very hot water or in the dishwasher. Simmer the rings and lids in hot water, but do not boil them. When the water in the canner begins boiling, fill the jars with the tomato soup, using a funnel to avoid spilling it. Leave headspace of 1/2 inch at the top of each jar, because the soup will expand slightly during canning.
- 7). Add 1 tbsp. bottled lemon juice to the top of each jar. The lemon juice increases the acidity of the tomatoes so they can be safely canned using a boiling-water canner. Run a rubber spatula around the inside edges of the jars to remove any air bubbles. Place the lids on the jars and secure the rings in place.
- 8). Place the jars carefully in the canner and replace the lid. Heat the water in the canner to boiling, and turn the heat down slightly to keep it at a slow, rolling boil. Process the soup for 35 minutes. Remove the cans from the hot water with a jar lifter, and set them on a towel to cool, leaving 2 inches between each jar.
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