Had a slight mishap the other day when one of the jars broke in the canner. I made the mistake of forgetting to put the rack in the canner before putting in the jars (so the jars were directly on the bottom of the canner). Just a case of too much heat being applied too quickly! Luckily there were no injuries and it was just tomato sauce, if it were something like maple syrup that takes several days to produce I would have been more upset!
There are multiple reasons why a jar make break.
