I've been pressure canning zucchini soup the past 2 years and it's a beautiful thing. This year I used a different pressure cooker, and I've just found out that 15psi on this pressure cooker is actually more like 13psi, and the internal temperature gets to 235 maximum when it says 15psi.
Well, that means that I didn't meet the rules of 240-250 degrees for 15 minutes and I have 20 cans of soup to show for it. I also learned while researching that it may not be a good idea to puree the soup before canning due to high viscosity and heat distribution, and it is indeed pureed, so I have two issues to combat. All of the can seals are still in tact, but it's only been a few weeks.
I've come up with a few options:
Re-can the soup. Just put new lids on, bring the water up to boiling for a minute or two before putting the lid on and building pressure. This will help with heat distribution from room temp up to boiling point since this is not freshly cooked and hot soup. I will also keep the water level in the pressure cooker to just below the fill level in the bottles to further combat the viscosity/heat distribution issue with the puree.
Sterilize then freeze the soup. Pour the cans from matching batches right into the pressure cooker, bring it up to pressure to kill anything that may have formed, then bring down to about room temperature inside of sealed pressure cooker, pour into containers and freeze it. This method addresses my fear of the pureed/viscosity issue.
Refrigerate, use ASAP.
Put the cans in the freezer.
Leave it alone. Is 235 degrees good enough? Are those extra 10 degrees important? Is everyone else in the world as precise as me, or was there a safety factor when they came up with those numbers?
I'm not sure which is the safest option. All I know is I dodged a major bullet by finding this out early. In the future I will can the soup before pureeing as well.