Nothing is more convenient than a can of soup, especially when you don't have the time or energy to cook. The homemade equivalent of the can from the store is to put up jars of soup by pressure canning them. The next time you do have the time and energy to make a pot of soup, make extra and can a few jars of it for quick and easy future meals.
This food safety rule applies to stocks and broths as well as soups with pieces of vegetables or meat in them.
If you are canning a clear broth or stock, be it meat, fish, poultry, or vegetable, process pint jars at 10 pounds pressure for 20 minutes, 25 minutes for quarts. If you live at an altitude that is more than 1000 feet above sea level, adjust the canning pressure and time.
For chunky soups that contain pieces of vegetables or meat, look up the canning time for the individual ingredients in the soup and use the instructions for the ingredient with the longest canning time.
For example, let's say your soup contains onions, celery, carrots, potatoes and chicken. A pint of carrots only needs 25 minutes of processing in the canner, whereas chicken needs 75 minutes. You need to process your soup for the longer time, 75 minutes. Again, if you live at a high altitude you will need to adjust your canning times and pressure.
Leave out any dairy or thickeners such as corn starch from your soup as they don't stand up to pressure canning well. You can always add them when you are ready to heat and serve the soup.
If your soup has dry beans in it, these must be cooked before they are canned.
Unfortunately, there is conflicting information about the safety of canning pureed soups at home.
The solution is to prepare the recipe for your pureed soup through the step just before you would usually puree it. Pressure can the soup in its un-pureed state, following the rule about using the longest canning time for the individual ingredients. All you have to do when you open the jar is heat and puree it before serving. That's not quite as convenient as if it were already pureed, but safety first! Or if you really want to preserve a pureed soup in a heat-and-serve state, freeze it instead of canning it.