Friday, September 3, 2010

Why Didn't My Jars Seal?

I know this post comes late in the season, when most of your canning may be finished, but I still want to put it out there for reference for next year and to possibly explain the reason for any problems you may have had.

Even though I've been canning awhile, I still end up with problems now and again.  Here are a few explanations for why things go wrong and what you can do to prevent them from happening again.  Even though it can be SUPER frustrating when your time and produce are wasted, don't give up quite yet.  Read what's below and try again.  Please?

Above all, follow the directions to your canning project precisely.   The advice below comes from a combination of my own experience and the "Home Canning Problem Solver" section in my Ball Complete Book of Home Preserving. 

Why Didn't My Jars Seal Properly?

1) You might have a faulty jar or lid.  If a chip has broken out of the rim, your jar will not seal.  Similarly, if a lid's seal (the reddish rubbery strip around the inside of the lid) is scratched or damaged, it also may not seal.  Check your jars and lids carefully before you use them.

2) You forgot to wipe the rims and food particles on the rim kept the lid from sealing properly.

3) The food was not heated before packing into jars.  This can cause the food/liquid to boil out, leaving residue between the rim and the lid.

4) There were air bubbles that were not removed before lidding and ringing.  I am constantly forgetting to do this!  To release the bubbles, use a non metal utensil (gently) between the jar and the food to release them.

5) There is not enough head space because you filled your jars too full.  This is what usually happens to me when jars don't seal.  I'm in a hurry, and I fill my jars too full.  The contents bubble out in the canner and residue from what bubbled out gets between the jar rim and the lid.  The jar(s) may seal at first, but they soon unseal.  You know this is the culprit if your jars feel sticky and there is residue under the rings (and your jars unseal, of course).  Next time, follow the directions closely as to how much head space to leave.  When in doubt, leave a little more instead of a little less, but not too much.

*My* solution to problem #3 (follow at your own risk- this is NOT recommended anywhere):  IF you notice that they haven't sealed or came unsealed while the jars are still hot and before having set out too long (think about regular food and how comfortable you'd feel leaving it sit out), you can remove and discard the lid, clean the rim with a damp paper towel until there is no residue present, replace any filling that may have bubbled out (NOT TOO FULL THIS TIME), place new lids on top, then rings and re-process.  This has worked for me many times when I've caught the mistake in time.  BUT, it's a pain in the butt.  The best thing is to do it right the first time.

6) It's possible your rings were screwed on too tight OR not tight enough.  Try to find a happy medium between the two, tightening the rings "finger-tip tight" meaning you meet resistance, but you're not using your whole hand to tighten it really snug.

Why Did the Bottom Fall Out of my Jar?

Good question.  It's happens occasionally to me and my explanation is that either my jars are too old (it's never happened with a newer jar) OR I've placed a cold jar in hot water OR a combination of the two.

There are shortcuts out there for canning and some of them work and some of them work only sometimes.  As an experiment, I tried a different method of canning peaches by adding the sugar directly to each jar, then filling them with hot tap water (versus using a hot syrup) and processing them and I lost several jar bottoms this way AND many of my jars unsealed.  Was it for sure because of the method?  I can't know for sure, but it's convinced me to return to my syrupy ways.  You have to weigh the risk for time saved.

Canning is hard work.  It's hot, sticky, time consuming and sometimes frustrating.  When it all comes together, though, it is incredibly rewarding.

Also, for those of you who can but do so saying a little prayer that the monster botulism doesn't come a-knockin', know that, per my almost pharmacist husband that there are only about 50 cases of non-infant (infants being given honey) botulism per year in the entire United States.  Botulism should be respected and steps should be made to can using proper methods, but I hope you can let go of your fear.  At least a little:-). Pin It


  1. how about browning at the top? My peaches are lovely, but the top ones are brown. I store them in the cool dark, but I'm afraid I should have filled them less with peaches and more with syrup... does that sound logical?
    -Pouting in SK

  2. Pouting in SK:-), You're right. If the liquid doesn't cover the peaches completely, the ones that are exposed the to air at the top may brown. So, make sure your peaches are covered and you have the right amount of head space- this should help your problem.

    This happens to me occasionally, and while the peaches at the top aren't as pretty, we still eat them if they are not terribly brown and they taste fine:-).

  3. Thank you for these tips, this was my first year canning and while a bit scary it is so rewarding to know that I controlled the ingredients in the foods my family will eat. Next year I'm going extreme and stepping up to a pressure canner! Robin

  4. Great post, thanks for all the helpful reminders. Seems after days of canning short-cuts become plentiful. Part of the canning craze!

  5. I don't understand #3. I don't heat my peaches/fruit/dill pickles before canning and I don't notice any boiling over. Can you say more?

    Sorry to hear the straight sugar didn't work for your peaches. I haven't lost any jar bottoms in ages (only once can I remember, and that was due to the whole cold jar in hot water thing).

    Don't your jars sit in the bottom of a large kettle while canning instead of in a hanging rack? Could it be that they are too close to the heat? Just a thought...

  6. Jennifer Jo, I don't know what happened for sure, but the only thing I did differently was the method. It was clear that the liquid boiled out (there was less in the jars and there was evidence of peach particles on the rims when I lifted the lids when they unsealed). I only set my pint jars on my canner bottom (and use a towel underneath them). I have a jar rack for my quart jars and that's what I was using for my peaches- so they weren't sitting on the bottom. I can't blame the method for sure, but I can't figure out what else it could have been.

  7. Great post. A few years ago I had green beans almost explode out of the jars in a pressure canner because I didn't know what "finger-tip tight" was. Also, so glad you mentioned the botulism...I get several questions each year from friends/family wanting to know if I am not worried about it.

  8. Thanks for the information! I lost half of my beans this year. They all sealed properly (or so I thought), but ended up coming unsealed in the days following. Believe me! They smelled awful! What causes the jars to come unsealed days (and even up to a week) afterwards??

  9. really really helpful tips!!! Thanks!

  10. Anonymous, If you're canning beans, I'm assuming you're using a pressure canner and I have very, very, very little experience with those. Sorry I can't be of more help. Anyone with pressure canner experience have any ideas?

  11. What a wonderful, informative and practical post! I grew up learning how to can from my Mom who (presumably) learned how to can from her Mom and so on...good farm stock in my genes. BUT, I don't always get it right...thanks for sharing your wisdom...I am sure it will be a blessing to many. :)

    Have a wonderful weekend!

  12. Again, a great post with tons of info. You'll be the first to know if I ever get the courage up to start canning on my glass stove!

  13. Hi!

    Thank you so much for this. You've inspired me to try canning. I've just ordered two dozen kilner jars, and they should be winging their way to me as we speak.

    I make jam and mincemeat by the gallon, but this'll be a new adventure. Wish me luck!

  14. I'm so excited that our first canning adventure over Labor Day weekend went great... thank you for all your info that helped ease my mind and fill my pantry.

    One odd thing we noticed - one jar had 2 caved in sides and we didn't notice it until a week later. The jars were new, the pears inside were fine, and we're still standing after sampling them... but that jar is now out of the rotation.

  15. Lordy - you have been sent to my by God himself. Thanks for putting my nerves at ease.
    Seriously. :)
    I make 6 figures annually as a careerist (lol), my husband is out of work and I believe in domestic and frugality living - and since our second child was born, I've had to bake cakes/sell pies to make money to keep us afloat. Now, I'm canning and part of the craze -It's saving us money - (we now have savings and no debt) It's been a blessing to me and my growing family. Your blog is amazing and I trust what I see - Your pictures give me lots and lots of confidence! GOD HAS PROVIDED!

  16. What about dill pickles that sealed at first and then came unsealed? I have made dill pickles for many (probably about 20) years, and I don't think I did anything different this year, but a couple dozen of jars have come unsealed, weeks after the pickles were made. Every day I go to the pantry and check, and like as not I find another jar unsealed. I made these by the simple method I have always used of filling the sterilized jars with all the desired ingredients (cucumbers, garlic, dill seed) and then pouring my boiling vinegar/water/pickling salt mixture in, wiping the jar top, then sealing with hot unused lids and a ring. The only thing I can think of is that although some of the lids were of course unused, they were from last year. Any suggestions?

    1. Hi, there. It is so frustrating when some jars fail to seal or become unsealed! You didn't mention that you put them in a hot water bath after you put your lids and rings on- did you? I've tried the open kettle method (just filling jars with very hot contents and then capping and I didn't have good luck with them sealing although I know others who do it with great success. If you did process them in boiling water, I only have two thoughts. 1) if some food particles boiled out and got stuck between the lid and the jar rim, there can be a false seal or 2) cracked or imperfect jar rims can cause a seal to fail. Otherwise, I don't know what to suggest. Anyone else want to venture a guess?

  17. Here's the thing: about 20 jars have failed, and one of them did have a seed in the seal - that happens sometimes - but the rest did not, and the jar rims are good. I checked them carefully. I did not water bath the jars, but then I never have, and I have never had this problem before.

  18. From IL here... I just had the same problem w/ my Dill pickles this year. All sealed initially but one- which is typical for one or two as I use the open kettle method. Have NEVER had problems past that. This year... these days following- I have over 10 jars unsealed now and I'm sure more to come. I'm so discouraged and upset by it since I've never had this problem. The only thing I can think of is I used NEW (not reused as we don't do that)- but new seals--- that were bought last season on clearance or the season before at discounted price. Could they really have gone bad just sitting on my shelf in the box?

    1. I don't think so. I've used new lids that were purchased the year or two before and they were fine. A friend had a similar experience with her peaches this year and it's happened to me before, too. I wonder if we didn't have a rolling boil going- if the contents didn't get hot enough. Or, if maybe the lids weren't soaked in hot water long enough to have the red rim get pliable enough. Just guesses here, but it surely is maddening!

  19. About #2, it is important, no matter whether you use paper or cloth towels to wipe your rims, that you use a clean part of the towel for each jar. Also, check the towel after each wipe to see if it picked up any food residue and rewipe with a clean part of the towel until no residue remains. Use a damp towel. A dry towel isn't capable of removing all the residue. I dip mine in the boiling/still hot water in my canner. I cringe when I watch canning vids showing the person wiping several jars in a row with the same piece of towel. One woman even held up her towel after to show how dirty the part of the towel she was using got.

    Warning: Many people started having multiple lid failures after Jarden, owners of Ball and Kerr, changed the coating formulation on the lids.

  20. Today, for the first time ever, my pickles did not seal (using open kettle method). Think problem was that the cucumbers and the syrup cooled as I packed....and jars cooled. My dh was in charge of heating them and he confessed he let "some" set on counter until I asked for more. Only the first 2 jars sealed properly. First thing in the morning I will dump the contents, reheat pickles (and jars) and give it another try. Very, very frustrating!


Just a friendly reminder, if you know me personally please try to refrain from using my name. There are those who may try to locate me, break into my pantry and steal my pickled beets. Thanks:-).

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