How to Check That Your Seal is Good

November 10, 2009(updated on October 3, 2018)

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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295 thoughts on "How to Check That Your Seal is Good"

  • 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.

    1. 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.

  • 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?

    1. 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.

  • 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?

    1. 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.

      1. 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 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 ?

  • 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!!

    1. 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.

  • 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?

  • 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?

  • 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?

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

  • 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?

    1. 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.

  • 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.

    1. 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.

  • 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.

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

  • I canned peaches yesterday ,and after quite a while maybe 2 hrs they still hadn’t popped down so I helped them and they stayed down on half, really did the 7 that didn’t. Also had to help.was. it because I did the cold pack method.? Cool peaches in sterilized jars going into a hot canner for 30 mins. Also tested them all this morning and they are all down don’t sound the same with spoon method but could be some are fuller than others.I have them upside down I figured if they leak they r no good.what r your thoughts? I’m a seasoned canner I should have done the hot pack method , I just didn’t want soggy peaches

  • Hi I have canned bread and butter pickles the last ones to come off hot water bath was late checked them 3 did not seal barely touched them and sealed should I put them in frig are they safe to eat. Thank you!

    1. Remove the rings and check to make sure that the lids are firmly sealed in place. If they are good, the seals are fine.

  • Hi, I tried canning pickles for the first time ever on Friday. I didn’t realize I didn’t have a tall enough pot to water bath can them so after filling them all, I stuck them in the fridge. I got a bigger pot but is it now too late to water bath them? Also, they sealed in the fridge so are they safe to leave out of the fridge or do they need to stay in?

    1. To can them at this point would mean taking a major hit in quality and crunch. And even though the jars sealed, it will be a relatively weak seal that may not hold up on the shelf. At this point, it would be best to keep those jars in the fridge.

  • Hi , my first time canning , I forgot to take the air bubble out on my green ketchup , look like they are properly seal , would it be ok?

  • Hi, I made some salsa for the first time. My jars seemed a little sticky after resting 24 hours. Lids are all sealed tight. Do I have a faulty seal somewhere? If so what should I do, since I can’t tell which jar it came from? Thank you.

    1. Sometimes jars leak a little during the cooling process. As long as the lids seems securely sealed, it isn’t an issue. Just wash the jars and store them in a cool, dark place.

  • I don’t have much experience canning however, I do have recipes from experienced canners. Yesterday I did cold packed peaches and tomatoes. After 12 hours I pushed all the lids down and they stayed down. Why do you suppose none of my lids went down on their own? Is it safe to keep them? I’m so frustrated!

    1. Tiffany, I’m really sorry you had this experience. Without being in the kitchen with you, I can’t begin to know why your jars didn’t seal.

  • My in-laws canned spaghetti sauce a few weeks ago. When I went to open one I could take it off with my fingers. Is this a good seal? The ones I can I can’t open with my fingers. I always use a can opener.

  • I’m new to canning. I canned pickles and when pressing on the lid it is firm, but only some of the lids are concave. Does this mean that the jars that are not concave didn’t seal even though the lid is firm?

  • I made canned salsa in July but I went to open a jar and it had a light seal. It had some pressure and sound but I was able to open it with fingers.Should I just throw them all away

  • Hello. A quick question…

    I’ve canned off and on for many years so I’m not completely new to the process. However, while placing quart size jars filled with apple pie filling into the canner earlier today I thought I heard one of the seals pop at that time. I still processed the jar, and all seems well although it’s still too early for me to investigate the jars too directly. Does that ever happen? A seal can pop when it first enters the boiling water bath?

    1. It could have formed a weak seal if it was filled and sitting outside the canning pot for awhile. It’s not a big deal though. You can still process it at that juncture and thus ensure yourself a strong, reliable seal (rather than the weak one you’d have gotten otherwise).

  • I canned pickled beets two days ago. I went to put then in the pantry and found one had not sealed. From what I have seen in your responses I should be able to put them in the refrigerator and they will be fine is that correct?

  • After making zucchini relish, I water-bathed following timeline from Ball Home Preserving Book. My seals all pinged lightly and the centers went down. However, I can remove the lids with my fingers with little effort. Are the seals good? Can I reheat and reseal this batch? It has been a week since I made it. Thank You!

    1. I can’t really give you more information about how to test your seals beyond what this post details. But lids should not come off easily. If you reprocess, you will compromise the texture of the finished product. You are better off refrigerating and using/sharing promptly.

  • I have a general question as I have some chicken and pork in the freezer that I would like to get canned up. I usually can around 40 half-pints of trout each year, and it has always turned out fabulous and never a failed seal. I recently had to purchase new lids and they were the Ball Sure Tight lids. I had never used them before because I had so many of the older ones left. Recently I canned some spaghetti sauce using the new lids, as well as pickling some Chileno peppers. Doing the seal test that I have done in the past, picking the jars up by the edges of the lid, and then just pushing up a bit against the lid, they were actually very easy to just pop off. I have never had that happen with anything I have canned before. The lids were all popped down/concave as usual. Now I am really concerned about canning the pork and chicken and having seals that are not actually as strong as they seem to have been in the past, and wasting an immense amount of meat. As I said, I can pry these lids of easily by just pulling them up with my fingers – I do get the de-vacuuming sound. How easily should this be able to be done? Is it the new Sure Tight lids. Any help would be appreciated. Thanks.

    1. I’m not sure what to tell you. I don’t think they should be that loose, but I haven’t had that experience with the newer lids. Perhaps do a test run with something less precious in the pressure canner and see how they perform there?

  • I made pomegranate jalapeno jelly. 3 pints didn’t seal. I put those 3 in the fridge to reprocess. It has been over 24 hours but right at 48 hours since I made the jelly. Is it ok to reprocess if it was in the fridge for 24 hours?

  • During the pandemic, the 2 piece lid/rings have been hard to find. My local Ace is carrying a brand called “Pur,” which is reportedly affiliated with Purrell according to an Ace employee. Any thoughts on canning with this brand or any other “off brands”? Are they supposed to be FDA approved? Thanks!

  • I pressure canned a few jars of green beans. It appears the one lid sealed but has a kink nonetheless. Should I be concerned? It “popped” indicating it sealed. Took the ring off and cap is tight. Just don’t want botchalism or something bad.

    1. The kink is typically an indication that the ring was applied too tightly and that the air wasn’t able to escape. The lids are designed to buckle in this situation to prevent the jars from breaking. I might put the jar with the kinked lid in the refrigerator rather than risk it on the shelf.

  • Today I made wild blackberry jam for the first time. I made sure the jars were hot and the jam had reached 220 degrees F when I poured the mixture into the jars. I heard the jars pop later, even though I didn’t hot water bathe them. Is this seal still safe? Thank you!

    1. Were the jars sterilized? While this is not the current recommendation for how to seal mason jars, as long as they were sterilized and the seal has formed, there aren’t any major risks. There is a small chance that the seals will fail over time, or that they jam could become moldy, but those are slim risks. If you are at all worried, you can always refrigerate the jars

  • I pressured cooked hatch chilis, 4 point and 3 quarts. I later read not to use can chilis in quarts and dedicated not at same time. I processed them for 35 min. At between 12-15 PSI but I noticed a couple of the lids had small dimples but the lids are on tight and concaved. What do you recommend?

    1. Unfortunately, I don’t have any experience canning chilis, so I can’t really advise you here.

  • I made peach salsa and then canned some peaches using Denali lids since Ball have been hard to come by. Five of the salsa jars didn’t seal and two of the peaches didn’t seal. I put them in the refrigerator and now they’ve sealed. Can I trust these or should I reprocess them?

  • Hi, came across this and Ive already learned a ton. I canned for the first time yesterday by canning some cowboy candy. I heard one pop and the other not. I didnt want to mess with them so I put them in my pantry under the stairs. I came back 24 hours later. The bottun was concabe and didnt pop on either of them. When I went for the lift test one did fine. The other did not, in fact, the lid shot off after taking the band off. Even eith the button rock solid. I put it in the fridge? Is it ok? Can it be reprocezsed?

    1. You don’t really want to reprocess a product like cowboy candy, because the added heat will soften the jalapeños and make them unpleasantly soft. The best choice is to keep that jar in the fridge and use it first.

  • I canned tomato juice 3-4 weeks ago. I had to use an off brand lid due to not being able to find the kind I usually use. Everything sealed but I just now realized it doesn’t seem to be a strong seal, I can pull the lid off with my fingers. It does pop tho. Is this juice good or should it be thrown out since it’s not a strong seal?

  • Made old fashioned “Catsup” (ketchup). Button on the lid of some jars, was not down. When I removed the rings, the lids were all secure when I picked up each jar by the lid and jiggled. Pressed the middle button on each of those lids and it went down and stayed down. It doesn’t pop back up when pressed again. Can I trust the seal? Do lids sometimes seal without the middle concaving?

  • I thought my blackberry jam was sealed properly, two weeks ago. It’s been out of the fridge since then. Today I turned one upside down and it moves and slides to the jar’s top. Is it any good? Thanks a milllion

    1. The movement of the jam in the jar has nothing to do with the quality of the seal. As long as the lids are on tightly, the jam is fine.

  • I seen on YouTube were a lady took a pen and tapped on the lids of her stored jars she said if it makes a pinging sould it’s good but, if it makes a dull thud then it has a false seal. Is this accurate

    1. I don’t think I’d rely on that as a seal check technique. I much prefer removing the rings, grasping the edges of the lid, and lifting the jar up an inch or so. That’s a much more reliable test.

  • In Preserving by the Pint you make a lot of use of 4oz jars, and I’ve tried to use them many times (with jam mostly), and I have never had a single jar “ping” as it cools off after the water bath. The seal seems ok around the edge when I check the next day, but the top does collapse after even a tiny big of pressure from my finger tip (just barely touching), but then seems set and doesn’t move. Would you think this is sealed? I haven’t tried the tapping test, but will in the future.

    1. Those jars don’t typically give that ping or snap sound because of their size. To test the seal, remove the ring, grasp the edge of the lid and lift the jar an inch or two. That’s the best way to test the seal.

  • hi!

    I bought a few jars+lids. And well, because i’m new to this world (usually i use jars i have at home) so i didn’t know that you can have lids without a button. So thats what i have! 100 jars and 100 buttonless lids……

    So, how can i be sure that my pumpkin jam is going to last a few months? I’ve done the boiling my jars, putting the jam, and then boiling again!

    thank you!

    1. Pumpkin isn’t safe for water bath canning, so the style of jars you used doesn’t really matter. I’d discard that product immediately.

  • If the seal did not pop on its own, but i tapped it lightly, and it stayed down, do i have a safe product?

    1. The only way to really check is to remove the ring and lift the jar holding the edges of the lid. That’s the best way to determine whether the seal is good.