Blend tomatoes, celery, onions, parsley, and garlic cloves together. Put through strainer. Cook for 20 minutes. Add butter, Gentle Sweet, tomato paste and salt. Bring to a boil. Wash 10 quarts jars in hot soapy water, rinse well. Add 1/2 teaspoon citric acid to each quart jar.**
Ladle into canning jars . Add lids and rings. Place in a hot water bath canner. Bring water to a boil and boil gently for 20 minutes. Remove form canner and allow to cool. 10 quarts tomato soup. I use this tomato soup in recipes that call for tomato juice/sauce.
*if you blend the veggies well, you will not get much waste. The food mill will get the larger pieces. I dislike skin and seeds in my soup.
** the butter will prevent the soup from boiling over.
***tomatoes can safely be canned with the hot water bath method. However if you are concerned that the ph level may be to high, citric acid may be added to lower the ph. Different types of tomatoes will have different ph levels.