Just follow the canning directions to a "T" and you'll be fine. Important thing is to leave that 1 inch open space at the top of the jar and do not screw the lids down like a gorilla. Barely finger tight, the steam has to escape from the jar during the process of canning, The lids will suck themselves down tight, I don't retighten the rings afterwards, I've never had one pop open. Also be aware not to put hot jars into water in the pressure canner that's cooler than the jars if you are doing a hot load.