Canning Jar bottom pops off during canning
Each canning season I have a canning jar that the bottom cracks off during the canning process. Anyone know why? The jars are checked for cracks, chips and sterilized before each use.
Best Answer
Having the bottom of a jar pop off is a symptom of thermal shock to the bottle.
Don't place cold bottles into hot water or refill a canner full of hot bottles with cold water-- there is a good chance of cracking a bottle.
Another consideration, though in my opinion less likely to be the issue, is that your rings on your bottles should be only lightly tightened-- just enough to keep the lid on.
When the bottles are processed, the air in the head space expands and some of it pushes out past the lid. When the jars cool, the air in the head space shrinks and, since there is no longer enough to fill the space, it creates a vacuum that seals the bottle. If there is no head space or if the rings are tightened too much, the extra pressure in the bottle will not be able to escape and the bottle can burst.
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Quick Answer about "Canning Jar bottom pops off during canning"
Having the bottom of a jar pop off is a symptom of thermal shock to the bottle. Don't place cold bottles into hot water or refill a canner full of hot bottles with cold water-- there is a good chance of cracking a bottle.Why are my canning jars popping?
When you're taking your jars out of the canner, sometimes they will immediately start popping. Generally, you'll put them on the counter and after a few minutes, they'll start popping. The popping sound when canning is a good thing IF it indicates that this lid is popping down. Just leave the jar on the counter.Why do Bottoms break out of canning jars?
Breakage can occur for several reasons: Using commercial food jars rather than jars manufactured for home canning Using jars that have hairline cracks Putting jars directly on bottom of canner instead of on a rack Putting hot foods in cold jars Putting jars of raw of unheated food directly into boiling water in the ...What happens if headspace is off when canning?
If too little headspace is allowed the food may expand and bubble out when air is being forced out from under the lid during processing. The bubbling food may leave a deposit on the rim of the jar or the seal of the lid and prevent the jar from sealing properly.What is a false seal in canning?
A false seal is a weak seal that can happen for a number of reasons. False seals occur when the products are not canned correctly, when jar rims are not wiped clean before processing, or if jars are not filled correctly.Help! My pressure canned jars froze and the lids popped off!
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Answer 2
I assume the bottom of your jars are not touching the bottom of the pan - you use a trivet. Thought I’d mention this, just in case.
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