Found a jar with a false seal from the canner loads last night. Let's talk about it.
The conventional advice is to wait and allow jars to sit and seal for 24 hours before washing and putting away. In my experience, this is creating problems and false/weak seals. My personal rule, if the jar doesn't seal shortly after leaving the canner, that jar is under suspicion. If the jar hasn't sealed within a couple hours, it is singled out and set aside/put in the fridge.
When pressure canning, it is usually easy to see which jar won't seal. If that jar isn't boiling when it comes out of the canner, watch it because it probably won't seal. If the other jars have finished boiling and all sealed and that one still hasn't sealed, put it in the fridge because you're not going to get a seal or if you do, it will be false. I would rather eat something sooner than find a jar of yuck on my shelf later.
Let's say you find a jar on the shelf that came unsealed. Do NOT try and talk yourself into SAVING/USING the product inside that jar. I don't care what it was and how much vinegar was in it; just don't. Chalk it up to a lesson learned. Let's not become a statistic.
The jar in question was boiling merrily last night. I left them set to go to bed; I couldn't wait my usual couple hours to check. Got up this morning to find the button still up and as soon as I pushed it, it clicked down. I know it hasn't been 24 hours yet, Margaret; I'm still not going to put that on my shelf. I stuck that jar in the fridge for my lunch today. (Stew! Yum.)
There's always a question of food safety and how long a jar can sit out before it is no longer safe to eat the contents. There's a reason the US is known to have the safest food supply in the world. The food prep, holding and serving rules are very strict and we waste huge amounts of food because of it. I'm in the process of achieving a food prep certificate and I've learned so much about what Mom and Grandma did "wrong".
I'm now going to use the "your kitchen, your rules" saying. In my own kitchen, when I am cooking for myself, if a jar stayed out on the counter overnight, I will heat and eat the contents. If I'm going to be cooking for other people, there is no way that jar's contents will be served to them.
Use the common sense that God gave you. Don't try to "save a buck" and eat something questionable. Don't uselessly waste food by allowing items to sit too long with a false seal and allow the product to spoil.