Secrets of a Vacuum-Packer: 10 Tips for Getting Lids to Seal on a Mason Jar

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Are you having trouble getting the lid to seal when vacuum-packing a Mason jar?

It’s a classic case of seeing things differently after you experience something yourself.

Over the last 3 years of blogging about salad in a jar (a method of preserving chopped lettuce in a vacuum-packed glass jar), I’ve had the occasional reader ask me why they couldn’t get their jars to seal. I would gently repeat the original instructions and most would write back saying something was upside down, backward, inside-out, topsy-turvy or whatever. And they finally got it to work.

Then it happened to me. I have one Mason quart jar in my cabinet that will not seal no matter what I do. NOW….I feel your pain, with apologies to all of you who have ever had difficulties.

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Wide-mouth attachment as seen upside-down

In this case, I think it is my jar although that may not be the case for you. Regarding the wide-mouth attachment seen above, the blue rubber must form a seal around the ridge at the bottom of the top of the jar (See below). If there are any bumps or other irregularities, it may be unable to form that seal. If you look carefully at the jar in the picture, you can see that the lowest ridge has some ripples. This is completely unnoticeable to the casual observer but I can feel it with my fingers. Looks like this jar will receive a new job description that doesn’t include storing lettuce.

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See the bumpy rim on this jar?


  1. Is the flat lid bent? (You can reuse these lids many, many times so this will occasionally happen.)
  2. Does the rim of the jar have a crack or chip?
  3. Is there a piece of food between the lid and the edge of the jar preventing a clean seal?
  4. Is the rubber gasket on the attachment dirty? Wash in soapy water.
  5. What brand of jars are you using? Do they match up to the wide-mouth attachment? The FoodSaver website recommends Ball and Kerr brand jars. However, these are not the only ones that work. One person did some research and found that out of 12 brands she tried, 10 worked and 2 did not. Trial and error may be the order of the day on this one.
  6. Is your jar a mutant like the one I described above? Use it for something else that doesn’t need to be vacuum-packed.
  7. Foreign particles may be blocking the hole in the attachment at the top where air is sucked out of the jar. If you are packing something powdery, try cutting a piece of paper the diameter of the jar and laying it on top of the contents to prevent the small particles (e.g. powdered sugar or flour) from entering the attachment.
  8. If you are using a hand-held sealer, you may not be pressing firmly enough, or at the right angle, or directly over the center to create a seal between your sealer and the top of the attachment. Sometimes, just applying more pressure to the white FoodSaver lid attachment while you are sealing will cause the jar to seal.
  9. If you are using a full-size FoodSaver machine with a port, your hose may not be attached securely and completely. Make sure it is inserted as far as it will go into the machine. Also make sure the hose to the attachment is inserted securely.
  10. No matter what method you are using, are you operating the machine long enough to pull out all the air?  You should hear a difference in the sound of the motor as it slows slightly. If you are vacuum-packing with a hand pump, be sure you have pumped it several times and then do it one more time.

FoodSaver suggests you try using two flat lids, one on top of the other if you are having difficulty getting a seal. Of course, you will remove the second lid when you are done as it is just laying on top. I have found this tip most helpful when sealing regular-mouth jars (as opposed to wide-mouth jars). For some reason, the smaller opening seems harder to seal, which is why I only buy wide-mouth jars if I’m purchasing new jars. Besides that, wide-mouth jars are easier to get the food in and out of and easier to clean.

If you are still having trouble or you have another suggestion based on your own experience, please leave a comment.

p.s. Just a reminder that the vacuum-packing process is not a substitute for heat canning. Perishable foods must be kept in the refrigerator even when vacuum-packed.

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{ 43 comments… read them below or add one }

rick jones June 19, 2017 at 9:42 pm

I have my own freeze dryer. it maybe is overkill, but I pack freeze dried food
in vacuum sealed jars with an oxygen absorber packet.seems to work very
good. i’ll let you know in 20 yrs.


Paula June 23, 2017 at 9:01 am

It might be overkill but…..:-)


Joanna May 6, 2017 at 3:07 am

Awesome website Paula, keep it up!
I really enjoy your content. My ideas have expanded so much because of your posts here. Thank you 🙂


Tammy July 19, 2016 at 4:54 pm

Does this method also work with dried fruit?


Paula July 26, 2016 at 5:37 pm

Yes. Also nuts and other grains, coconut, cereal, seeds, etc.


Martha June 30, 2016 at 9:11 pm

Help. The blue gasket came off and stayed on the jar. I removed it without paying attention to how it was positioned. I don’t know how it goes back into the jar sealer. Does the open or closed side of the gasket go facing the jar?


Paula July 1, 2016 at 4:58 pm

Hi Martha,
Hoping you got your jar sealer put back together by now. The larger flap goes toward the jar.


Margo Daugherty June 18, 2016 at 6:41 pm

I had the same problem with the regular size lids. What I was told to do was to
put the lid on the jar, then put another lid inside the lid sealer, and then go through the sealing process. This works great for me. Sometimes both lids
stock, and very carefully I have to pry the top one off. I just keep an old lid in the
box with the sealer.

The wide mouth lid sealer works great just as it is

Hope this helps.


Mary May 14, 2016 at 10:26 am

I finally solved the problem by a combination of 3 things. Using two lids but heating the lids with a hair dyer before placing the on the jar and putting the cap on. Once the cap is on, I give it a little twist to ensure the lids are seated properly. Never had a problem since. Just thought in canning the lids are warm to hot from being in the water so thought to heat the lids.


Kim April 20, 2016 at 8:24 pm

Thank you for the two lid trick on the regular mouth jars!! I thought I was going crazy because my machine works fine. That did the trick! It got everything lined up beautifully.


Jessica Gopinko March 26, 2016 at 12:18 am

Great informations on vacuum sealer. I am currently doing some research and found exactly what I was looking for. Thanks for guide!


Melissa March 20, 2016 at 2:46 pm

Hi Paula,
I couldn’t find the cheap hand pump, so I went ahead and bought the Foodsaver handheld vacuum. I don’t have the Foodsaver wide mouth jar attachment. Can I use the hole prick/electrical tape method with the handheld vacuum?


Paula March 20, 2016 at 3:22 pm

Yes, Melissa. You can. See this post.


Steven March 4, 2016 at 6:01 pm

Just replaced a broken Jar Sealer and also bought a new tube. The old was cracked, and before I discovered the crack had tried to clean the machine gaskets etc. Also adjusted the altitude setting on the bottom, but believe it back to where it was.

I can seal jars, but not get them machine to offer the green light or turn off. Tried new and old tubes and jar sealer gaskets.

Any ideas where my problem may lie?


Paula March 6, 2016 at 10:15 pm

I am not a technician or repairman so I don’t really know. But I do know the average vacuum pack machine seems to have a relatively short life–especially if you use it almost daily like I do. I feel good if I can get 2-3 years before I have to get a new one. Maybe another reader will have an idea. Paula


Sean Tite February 17, 2016 at 8:33 pm

The vacuum sealer makes a weird noise as it sucks the air out of the jar. The closer the sealer gets to creating a vacuum in the jar the higher pitch the noise becomes. The vacuum sealer will automatically stop when a vacuum has been created in the jar.


Patsy August 15, 2015 at 4:12 pm

Thanks so much for the double lid trick. I just did 2 quart jars of Raw Pistachio Kernels. I was getting very frustrated before I read the “double lid” trick. I also had to gently hold down the sealer attachment to get the seal. Now, back to the kitchen to vacuum seal jars of Hersheys Cocoa and anything else I can find to vacuum seal in a jar. 🙂


Tracy July 26, 2015 at 6:58 am

I’m so greatful for your website as I am planning to give salad in a jar for my birthday at work. Already bought the bottles last month. Blessings


Anne wood June 26, 2015 at 1:53 am

Hey great tips Paula it totally helpful!


rudy January 29, 2015 at 8:35 pm

hi, we have tried all the suggestions but so far what has worked for us in mhy home was to boil the lids to soften them up . hope this helps


jojo883low December 24, 2014 at 12:52 pm

Thank you!! I have had a very difficult time getting my regular mouth jars to seal when using my vacuum sealer. I added another lid as you suggested and PRESTO!! It worked!! Thank you!!


Lynn December 3, 2014 at 8:21 pm

Thank you for the informative review! I have a question regarding perishables. I have FoodSaver & just ordered the lid for jars & will buy wide mouth jars. Does this method extend a “best before” date? I have a large bag of cat kibble that expires Feb 23, 2014 & I wonder how best to store it once in the jars. Do I keep it in a cupboard, the fridge or freeze the jars? And do I still need to use it by Feb 23rd? I’m just not sure what the point is for dry foods other than the obvious, like keeping little critters out, but that’s not my issue. I need to extend the life of the kibble as the formula changed & this is my last bag of the old formula. I can’t use it all up by Feb 23rd…Tks for any advice!


Paula December 4, 2014 at 8:01 am

I don’t have a good, authoritative answer for you. With dry human foods, I can taste that they are fresh much longer than they were before I started vacuum-packing everything in mason jars. But I couldn’t tell you for sure how much longer–I just have to smell/taste. I am afraid of most dogs so I have never had a dog and have zero experience with dog food. And I’m pretty sure you don’t want to taste it yourself. Maybe you could ask the FoodSaver people?


maj October 31, 2014 at 12:03 am

I’m not from the US, so the ziploc vacuum isn’t really an inexpensive option. Wondering if this would work? Aka, how big is the hole on the top of the foodsaver suction device?


Erica July 6, 2014 at 7:45 pm

Way late to the party here, but I found you on a google search because I couldn’t get my jars to seal. Was making me crazy! I’m not doing this for lettuce, but for a conserve I’m going to freeze and I wanted to remove the air before the freezer. The 2nd lid worked like a charm.

Thank you for posting this!!!


lynne March 12, 2014 at 6:30 pm

Hi I made two jar salads the other nite and just put tops on with my hand Should no be vacuuming first? Seems like a large expense?


Paula March 13, 2014 at 7:57 am

Hi Lynne,
I’m not exactly sure what you mean by “jar salads”. If you mean you put lettuce and other veggies in a jar together, it is best NOT to vacuum-pack them. They won’t stay fresh long but since you only made two jars, I guess it won’t take you long to eat them. See this post. On the other hand, if you put only chopped lettuce in the jars and you want them to last a week or longer, they will stay much fresher when vacuum-packed. It doesn’t have to cost a lot of money. See this post. You can also do it cheaply with a hand-held vaccuum-pack machine. See this post.


Toni November 29, 2013 at 6:54 pm

How do you unseal the lid without bending it?


Paula November 29, 2013 at 9:49 pm

Very carefully. I use a pop top can opener.


Marla Riedling April 27, 2013 at 1:27 pm

I would like to add one little thing that can also make a difference in the longevity of ANY fruit or vegetable: use a porcelain knife!!!!
You can get them at any Harbor Freight store and I just noticed they have them at Walmart now too. The difference between using steel versus porcelain is incredible! No more brown edges. Period. Try it and you will be sold! 🙂


Paula April 27, 2013 at 2:36 pm

Hi Marla,
Thanks for writing. I did a little experiment with knives and vacuum-packing in regards to chopped romaine lettuce. You might find it interesting. You can read about it here.


Paula Erisman April 16, 2013 at 8:07 am

I have not been successful printing any of you instructions from the print/pdf. Not sure if it is my printer for sure. Thought I would let you know. I end up highlighting and printing that way. Your method for making Greek Yogurt is the best. Thanks so much for simplifying it. I have done it twice now and have told several friends.


Paula April 17, 2013 at 7:17 am

Hi Paula,
Sorry you aren’t having good luck with the print button. I just tried it myself and it worked fine so not sure what to tell you. But if highlighting and printing works for you, then all is well, although not as convenient. 🙁


TimAyn Stafford April 9, 2013 at 1:16 pm

Thank you for sharing this awesome technique! My foodsaver does not have a attachment port, would the same result occur if I used a food sealer bag?


Paula April 10, 2013 at 6:21 am

TimAyn, I do not use the bags for lettuce because the leaves would be crushed. The jars protect the lettuce.


Karen M April 6, 2013 at 1:16 pm

I love this and am on my second batch of lettuce (Romaine and Iceberg) BUT I also use it for cucumbers and another jar for green peppers. My husband and I are retired and with just the two of use, we don’t use up some of the produce as a family would. I am going to use a smaller jar for my ginger and for garlic. Before I know it – I might have a whole refrigerator full of jars! Thanks I love this idea.


Paula April 6, 2013 at 10:11 pm

Hi Karen,
Thanks for writing. Both my refrigerator and pantry are full of Mason jars which also means my dishwasher and cabinets are often full of them too.


Betty April 6, 2013 at 1:02 pm

I’ve never tried the double lid method- that will come in handy! 🙂


Rachel April 6, 2013 at 12:29 pm

I wipe the jar rim with a damp paper towel before applying the lid. It always works for me. Rare time it does not, I use the double lid method.


Paula April 6, 2013 at 10:12 pm

Good habit, Rachel.


Vicki W. April 6, 2013 at 4:31 am

I was just talking with a friend and suggested something I would like to add. I always use a canning funnel when I add my lettuce or pantry goods to the jars. That way the jar rim stays nice and dry when packing lettuce, or powdery things don’t get on the rim to interfere with the sealing process. The funnel only costs about $1.50 and lasts forever.


Paula April 6, 2013 at 10:25 am

Thanks for the suggestion about the funnel. Great idea! Don’t take up storage space either.


Vicki W. April 5, 2013 at 3:23 pm

Thank you, Paula, for this post. I am definitely passing it on to friends who are vacuum sealing mason jars. I agree with you that it is much easier to seal the wide mouth jars. If buying new, that’s what I go with. However, I have a lot of the regular mouth sizes and as I store dry goods in my pantry, I do use them. The double lid trick is what usually works for me. If I had not found out about that trick, I imagine I would have been one frustrated lady, lol. Just yesterday I showed a young man (whose family is into emergency preparedness) how to vacuum seal with a Ziplock hand pump and a widemouth Foodsaver jar adapter and jar. It took several tries (even with me guiding) to get it. But once he got it – he got it! So hopefully everyone will not give up. And I really think your videos are REALLY helpful. If they follow your suggestions, I’m sure they will have success.


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