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I canned a bushel of pickles 2 weeks ago. When I finished up that morning, all the jars were sealed. This morning I noticed that about a dozen jars were not sealed. Just the opposite. The lids were puckering out to the point of bulging the lids out. I have been canning for more than ten years and I have never seen this before. What would cause this and are they safe?

marked as duplicate by Catija, kiamlaluno, Cascabel Oct 10 '16 at 18:22

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  • Howevermany years you've been at it, this is a clear sign that this time, something was not right. Toss 'em. – Ecnerwal Aug 28 '16 at 18:31

Canning jars bulging, particularly after a period of time, means that some sort of gas is being produced from within. That likely means that they were not, or are not now, sterile. I would discard.

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