How to Check That Your Seal is Good

concave lids
I got a question tonight from a reader of this blog about seal quality and as I was writing her back, I realized that there may be more of you out there who could benefit from a brief seal-testing tutorial.

When it comes to canning, sometimes you miss the pinging sound that gives you auditory confirmation that your jars have sealed. Just because you didn’t hear it doesn’t mean that the jars didn’t seal. Here are some ways to test….

  1. Press down on the center of the lid. Does it move up and down or does it feel solid and concave? Solid and concave means a good seal, movement means no seal.
  2. Tap on the lid. Does it sound tinny or hollow? Tinny means sealed, hollow means poor or no seal.
  3. Unscrew the band you used to hold the lid in place during processing. Now attempt to pick your jar up holding onto nothing but the lid. If you have a good seal, you should be able to do this easily. You’ll know pretty much right away when you remove the band whether your seal is good.

How else do you guys check your seals? And, while I’m answering questions, who else has got one?

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244 Responses to How to Check That Your Seal is Good

  1. 101
    Britney Adams says:

    Hi ladies,

    I made strawberry jam last weekend and all the tops sealed. However, today I noticed one was up and when I touched it, it went down and has stayed down. Should I throw this one out?

  2. 102
    Callandra says:

    Great Article! We just made our first batch of pickles – the jars were just a touch too big for our canning pot, so when we took the lid off of of the first batch, we realized the water was about 1/2 below the top of the lid. I popped those back in for about the time I think the water was too low. One of the lids is now convex – I am assuming that seal didn’t work? Two questions
    1) How long do i wait to actually eat pickles ( they need to sit right?)
    2) How long will the one with the crappy seal last in the fridge?

    Thanks so much!

  3. 103
    Lori says:

    Canned pickled cabbage. All jars appeared to seal. Heard them ping and all are depressed or concave. Theres no give in the lid. However, at the right angle I can see a slight ring in the center. Are these sealed and safe?

  4. 104
    Stephanie says:

    I pressed the middle of the lids down before some of the jars had a chance to pop on their own. I’m a first timer and didn’t realize that I wasn’t supposed to touch them! They’re staying down on their own now (not going up and down when I press on them). Did I screw up my pickles??!! Lol Or will they be ok? Thank you 🙂

  5. 105
    Cynthia says:

    If they didn’t seal what do you do?

    • 105.1
      Marisa says:

      If you caught the seal failure within the first 48 hours, you can either put in the fridge or try to reprocess is (though if the texture of your preserve is important, this isn’t the best option). If a jar isn’t sealed and it’s been awhile since you made it, it’s better to throw it away.

  6. 106
    Megan Aasen says:

    Hello, i have made several jars of pickled beans and they all sealed until yesterday now i cannot get a seal? i haven’t changed anything and the pickled carrots seal it is just the beans that refuse to seal now.

    • 106.1
      Marisa says:

      Could it be that you’re using a different batch of lids? Are you doing the boiling water bath process properly? There’s no reason that I can think of why your beans wouldn’t seal while everything else does.

  7. 107
    Lana Johnson says:

    I made cran-blueberry jam recently and all four lids popped, so I felt sure they were all sealed. Days later, not sure how many, but under a week we discovered one lid unsealed. We immediately put it in the fridge, but are unsure now if it’s safe to eat. What do you think?

    • 107.1
      Marisa says:

      I think it’s fine. The worst that can happen with that jam is a little mold. If the surface looks entirely normal, it is safe to eat.

  8. 108
    ryan says:

    hi new to canning , I didn’t hear my jars ping and mistakenly touched them, they didn’t seal , right away I used a tea towel to help me push the centre down for a minute and the lids of now sealed and pass the lift test the next day . Are they going to be OK?
    thx
    ry

    • 108.1
      Marisa says:

      I can’t judge the safety of your seal. You’re not supposed to touch the lids in any way, and holding down the lids is a sure way to give yourself a false seal. They can sometimes take as long as half an hour to seal.

      • ryan says:

        thx for the quick response, I am definitely going to be hands off next time. I panicked because every book I had said I should hear the ping right away . So even though with the bands off, when I lift the jar by the lid and it doesn’t come off its possible I have a false seal ?
        thx
        ryan

  9. 109
    ryan says:

    thx for the quick response, I am definitely going to be hands off next time. I panicked because every book I had said I should hear the ping right away . So even though with the bands off, when I lift the jar by the lid and it doesn’t come off its possible I have a false seal ?
    thx
    ryan

  10. 110
    Amber says:

    I just tried canning for the first time ever tonight. I made up a big batch of strawberry jam. I followed my recipe to the letter but I don’t think I got a good seal. I didn’t hear any kind of popping sounds when they came out and the button on my lid is still popped up. I pushed the button in on a couple of the jars before I decided to turn to google and came across your blog. Help please!!

    • 110.1
      Marisa says:

      Did you process the jars in a boiling water bath canner for the proper amount of time? Was the water at a full rolling boil the whole time? Were the lids relatively new? Jars sometimes take 15-60 minutes to fully seal.

      If the answer is yes, you can always try reprocessing with new lids.

  11. 111
    Susie says:

    I wonder if you’ll see this….if not, no big. I just canned a few jars of dilly beans this morning. I thought I laid out enough lids before jarring the beans and spices, so I was surprised that I didn’t have enough when I got to the last jar.

    I realized, seeing that one of the jars’ centers hadn’t popped, that I had maybe doubled up on the lids – two for one jar. I unscrewed the lid, and sure enough….there were two flats. I carefully removed the top flat lid, and the other lid was sealed.

    So, two questions: can I reused the lid that wasn’t really used as a lid in the first place, and do I trust the seal on the jar?

  12. 112
    T. Kay says:

    I made sand plum jelly yesterday. Upon removing them from the water bath, the lids popped down almost instantly. I’ve never had that happen so quickly before. Any thoughts on that?

  13. 113
    Jane says:

    I canned relish today. It was hot when it went in to the jars. Processed for 15 minutes. Some jars appear sealed when coming out of the bath. Can they seal during processing?

    • 113.1
      Marisa says:

      It’s unusual for the jars to seal while in the canner, but if the tops were at all exposed, it is possible.

  14. 114
    Seth says:

    I canned chokecherry syrup the other day. After about 12 hours only maybe half the jars had popped down. I just barely touched the tops of the ones that didn’t and they did pop down and have stayed down. I removed the rings and one lid popped up the rest stayed down. Do you think they are safe? Too much head space?

    • 114.1
      Marisa says:

      If the lids have stayed down, they are ok. If they popped up, they should be refrigerated. Not knowing how much headspace you left, I can’t say whether that was the issue.

  15. 115

    I just canned pickles for the first time today – but didn’t use a hot water bath. I received the recipe off of you tube (maybe a mistake!) which had you heat the glass jars in the oven for 20 minutes at 250 bring the mixture to a boil, add the garlic and dill then pack the pickles without any touching the top, fill with the boiling mixture (water, vinegar, pickling salt) to the very top, close and then turn over on the top of the lid. I haven’t heard any popping sounds in the past about 3 hours, turned the jars back on the bottom and checked the lids most are down. A couple have very slight movement (which I probably checked too soon before cooling?). What would you recommend that I do? Next batch I will use a hot water bath to make sure it is a really strong seal.

    • 115.1
      Alison says:

      That is not a safe canning practice. Acidic foods (like pickles) need to be water bath canned to kill any botulism spores. Botulism can kill a person in a couple of days and is not to be messed around with. Please toss that batch and follow an approved canning recipe next time.

  16. 116
    Teresa says:

    Does the loudness of the ping when lids seal determine how well they sealed? I made salsa and normally the ping is quite noticeable. Tonight with this batch I did hear it but was slight. Thought maybe lids were not good.

    • 116.1
      Marisa says:

      The loudness of the ping has nothing to do with the quality of the seal. Some lids seal loudly and some seal quietly.

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