Canning Lids Didn't Seal? Common Reasons Why Canning Lids Don't Seal

Canning Lids Didn't Seal? It Happens to Everyone Sometimes

I grew up helping Mom with canning in the summer heat- no air conditioning. It was a day long process. But the taste of those homemade jellies, pickles, and other delicious canned goodies was well worth it.

There are few hobbies more satisfying than home canning. Home canning is such an age old tradition. Not to mention it's a smart and frugal way to save money on groceries.But there are also few things more disappointing than to make up a big batch of canned food only to find out that the canning lids didn't seal correctly.

Read below to try to avoid this sad canning scenario. Also, see how to know if canning lids are sealed. There are a few reasons why canning lids don't seal. If your canning lids didn't seal properly, it could be one of these common reasons:

It would be a shame if the canning lids didn't seal on these delicious home canned tomatoes! photo: @flickr
It would be a shame if the canning lids didn't seal on these delicious home canned tomatoes! photo: @flickr
Home canned peaches and applesauce photo: newrambler @flickr
Home canned peaches and applesauce photo: newrambler @flickr

Common Reasons Why Canning Lids Didn't Seal Properly

The jar itself was defective. Before canning, inspect each jar carefully. The rim of the jar is the most important. Check for any cracks or nicks. If it has even one, don't use it for canning. It's also possible that the lids were defective, especially if they were old canning lids. It's always best to start with new lids. And never re-use canning lids.

Probably the most common reason canning lids don't seal properly is not leaving enough head space. Leave about half an inch of space from the level of the canning jar contents to the rim of the canning jar. Check the canning manual to find out the exact levels needed. Different foods require different amounts of head space. If you don't leave enough room, the contents of the canning jar will boil and get underneath the lid. As the jars start to cool down, this creates space for air to enter again and prevents the canning lid from sealing.

Another reason maybe why your canning lids didn't seal is that the canning jars didn't get hot enough. Either the water temperature wasn't hot enough or the canning jars weren't left long enough. The canning jars must come to a high enough temperature in order to form a proper vacuum that creates the seal. Often you will be able to hear as the vacuum is created, as the cans will make popping noises. So, if you hear popping noises coming from your canning jars, don't be alarmed. That's a good thing!

One of the most common reasons for canning lids failing to seal is that contents of the jar had gotten on the jar rim or spilled on the lid where it seals. Always make sure to wipe the rim of the jar carefully with a clean cloth after filling it.

Also, be sure that you don't tighten the jar lid bands too much. You don't have to tighten the canning lids so strongly that it will take a wrench to pry them loose. As a matter of fact, that is exactly the wrong thing to do. Simply tighten the canning lids as if you were closing a jar of pickles. If you tighten them too much, air can't escape and a vacuum seal can't form.

It is possible that the canning lids didn't seal correctly if the lids weren't kept in slightly simmering water before placing on the jars. This is necessary to make the glue on the lids tacky. If the glue is not warm enough, it won't make a proper canning seal.

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Canning Lids Didn't Seal? Common Reasons Why Comments 8 comments

Hello, hello, profile image

Hello, hello, 6 years ago from London, UK

Thank you for a great hub adn good advice on Canning.

ann 6 years ago

thanks so much for the info. lucky only one jar didn't seal

Kristy 6 years ago

I am so frustrated! I know it's overfilling them!

Loretta 5 years ago

I canned pears in syrup and the lids sealed but have a little bump on the top. Is this really sealed or should I just eat them now?

mary615 profile image

mary615 4 years ago from Florida

I use this method to preserve a lot of food, even cooked food. I wrote a Hub on making a cake in a jar, and also did one on preserving pecans in Mason Jars. May I link this Hub into the one I did on the pecans? Many thanks. I voted this UP, etc.

waitleys profile image

waitleys 4 years ago from Missouri

Thanks!! Couldn't figure out what was going on and since I have no canning experience I didn't have anything to fall back on. Thanks for the help. Off to finish canning!

Stephanie Lynn 3 years ago

How exactly will I know if my lids have not sealed!? thank you for this hub so much..I Just canned for the first time I'm pretty good at following directions but I did not leave my libs in simmering water. So, Just to be safe how exactly will i know my canning didn't work?

John 3 years ago

I canned some pickles last night and the lids did not ping? I pushed down the little bubble on the top and it stayed down with a ping..does that mean it's sealed at this point?? Do I redo them by putting new lids and reboiling?

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