DIY Airlock: Fruit and Veggie Ferments

This post may contain affiliate links. We only recommend products and services we wholeheartedly endorse. Thank you for supporting Traditional Cooking School by GNOWFGLINS with your purchases. Our family thanks you!

You’re going to love this! Jen, a GNOWFGLINS eCourse member, came up with a do-it-yourself airlock for fruit and vegetable ferments. She got the idea from seeing a commercially available product and thought, “I can do this, and at a fraction of the cost!”

Once her airlocks were made, she compared finished ferments: those done in a plain old Mason jar versus in her DIY airlock. She shares her results at the end of this guest post. Thanks, Jen, for sharing your idea with all of us! –Wardee

I’m still enjoying making fermented veggies! My cabbage tends to get supper bubbly, so I’ve started using airlocks. I also wanted to keep from opening the lid too much, to let the air out, during fermentation.

Here’s How I Made My Own Airlocks

I purchased 3/8″ rubber grommets at the hardware store. I purchased the airlocks at a local wine and beer hobby store. They have all kinds of groovy stuff!

I first drilled a 3/8″ hole in the top of the lid (secured with a clamp on a work bench) with a 3/8″ drill bit and drill. Then I inserted the grommet, which was not easy to do. I had to use a small flat headed screwdriver to help get it into place. When I went to wedge the end of the airlock into the grommet, it wouldn’t fit snuggly, so I had to remove the rubber grommet and drill a slightly bigger hole. I’m unsure of the size of the bigger bit, but it was the next size up. Then I inserted the grommet and the airlock fit better. Nice and snug.

The Results

I could definitely tell a difference between a jar of cabbage that had the airlock, and the one that did not. The flavor from the cabbage with the airlock was much better, the cabbage was crunchier, and my digestion of the cabbage improved. The ginger carrots fermented with an airlock jar tasted better than the one without as well. I plan on using the airlocks in the future!

The Cost

The airlocks were $1.25 at our local brewery hobby shop.  I’m sure you can get them cheaper online. The same brewery hobby shop sold the rubber grommets for 35 cents each.  Before I saw those, I bought a package of 5 grommets at my local hardware store for $2.45 per package.  One may be able to find the rubber grommets sold individually at a large hardware chain like Lowe’s, which I plan on doing if I have to buy more in the future. A quart size mason jar is about 90 cents.

Total cost: $2.50 per quart size jar with airlock.

Great, isn’t it? Thanks, again, Jen! I’m always looking for guest posts. If you have an idea or desire, please use the contact form to let me know. Speaking of the contact form, it hasn’t been working for awhile. If you’ve used it to contact me and I haven’t written back, that’s why. I am sorry about that and have fixed it. Please do resend your messages!

I’m sharing this post (a day late) in the new blog hop carnival, Simple Lives Thursday, which I’m co-hosting. “Consume less, produce more.” I’m also sharing it with Fight Back Friday! hosted by FoodRenegade, who just birthed her third baby, Alina Mae, at home. Congratulations, Kristen!

This post may contain affiliate links. We only recommend products and services we wholeheartedly endorse. Thank you for supporting Traditional Cooking School by GNOWFGLINS with your purchases. Our family thanks you!


  1. says

    Ok, now I’m intrigued! I’ve seen the commercial one, but never knew how it worked. So once you put the air lock on, what do you do with it? Open it occasionally?

    • sharri stowers says

      i make homemade wine and what is here is what i use….. the airlocks are what is pictured (the funny looking tube aparatus…. it is then filled with water and i would insert what is called a campden tablet it is sulfer in composition this tablet will prevent gnats from wanting to get into your fermenting goods…..the air just rises from the jar and upward to escape thru the water…..alll these components can be resanitized and reused over and over thru the years just like your canning jars

  2. JenE says

    Hi Tara! Jen here. No, there’s no need to open the air lock. One puts water into the air lock chamber. There is a fill line on the chamber so you know how much water to add. The water allows the ferment to “burp” on it’s own, letting air out, but no air gets back in. Make sense? : )
    I also posted my pics at the GNOWFGLINS class forum site under the Natural Pickled Foods: Questions and Impressions.

  3. Cheryl Lee says

    Fantastic idea! Thanks!

    Haha! @ WK (Jen’s brother, hee)… she could! And, I would happily buy them. 😀

  4. says


    Thanks so much for sharing this! I bought one of those big gallon sized fermenting jars that uses the airlock and love it, but it’s not always practical to make a gallon size of everything, so having a smaller option would be great! I love that these are so easy to make and I’ll have to make up a few smaller ones to use with smaller batched ferments. This would make a great gift as well!


    • says

      Susan — That’s a good point! And 1/2 gallon jars can be made, too. Even gallons, if we could come up with an airtight lid. As far as I know the gallon jars are not quite airtight.

  5. JenE says

    Thanks Cheryl!,
    My brother and I are discussing putting packages together. I’ll keep folks updated : ).

  6. says

    Wardee, I love this. I have purchased one airlock that I feel was way overpriced after seeing it! I love it though and will for sure make my own! Thanks for this post!

  7. says

    Oh jeez! I wish I’d thought of this. My husband brews beer and we’ve got a bunch of those airlocks laying around, plus several quart size canning jars. Genius!

  8. JenE says

    Just a quick note… be careful when wedging the rubber grommet into the hole in the lid! The just-drilled edge of metal can be sharp!

  9. vesperlight says

    I can remember my dad making an airlock for a jug of fermenting apple cider. He bought a rubber cork with a hole in it and put plastic tubing through the cork. He put the cork in the bottle of cider and ran the tubing into a jug of water next to it. Air bubbles came out through the tubing and bubbled into the jar of water, but air couldn’t come back the other way.

  10. Michelle says

    I just made sauerkraut this morning and tried something new…but I am wondering if I am going to have a disaster on my hands! I have a vacuum sealer mason jar attachment that vacuum seals the jar with the lid on. I guess it has removed the air in between the liquid and the lid. Am I setting myself up for an explosion or has someone else tried this?

  11. JenE says

    Hi Vesperlight, was your grandfather’s set up kind of like this one?

    Hi Michelle, I don’t know anything about using the vacuum sealer. Perhaps someone who knows better will chime in. Seems to me the excess air created during fermentation needs to go somewhere, but I’m still fairly new to all this.


  12. vesperlight says

    Jen – yes, kind of like that, but without the fat plastic part just above the cork.

    Michelle – I think the good lacto-bacteria need some oxygen to grow! I don’t want to be an alarmist, but you could be setting up an environment for anaerobic bacteria (like botulism which is not detectable by taste or smell) to get a foothold.

    Wardee may have better advice than I do though.

  13. Michelle says

    OK, so when I ran to unscrew the top of my vacumm sealed jar, it was already loose–I guess the bubbles must have just pushed it right up! So hopefully it’s OK that it went a few hours being sealed…
    I bought an airlock at my bewery store. The guy actually suggested just running a peice of tubing into a jar of water, as was listed above, but for $1 I figured I’d go for the airlock. Don’t exactly have tubing just sitting around…

  14. says

    Jen you compared the flavor of the kraut made with the airlock to that made without but curious how you made that without. Did you just use plain old canning jars with closed lids? or were you submerging the cabbage under liquid the whole time as with a crock?

  15. JenE says

    Hi Sustainable – Yes, I used ball jars. I made both jars in the same manner (following Wardee’s recipe), and at the same time. The only difference between the two was the airlock. I’ve never tried the crock method.

  16. says

    Has she decided to sell these yet?! I could use a few! Veggie ferments, secondary DK ferment hmmm i can think of all kinds o fuses and we don’t even drink! hah lol

  17. says

    I’m totally unfamiliar with airlocks, but I just ordered some from my nearest city to make quart fermenting jars (or I might do a couple half-gallon size). My question is after the initial ferment at room temp do you replace the airlock lid with a standard lid when you put it in the fridge? Or do you open your fridge door and see a line-up of jars with strange-looking topknots on their heads? I’ve made fermented salsa, pickles, sauerkraut and beets for the past 3 years but always with a regular jar lid (and mixed success, especially with the pickles). I’m looking forward to this improved method! Thanks for your input.

  18. JenE says

    Ack! Hope it’s not been to long for me to reply! ; )
    Yes, once the ferment is done, I replace the lid with one that doesn’t have a hole in it.

  19. Alan says

    You should be aware that the grommets you get at hardware stores are NOT food safe! Also, it is hard to get a good seal with canning jar lids, the lids are designed to ‘heat seal’ when hot-water canning, not to provide an airtight seal just by screwing on.

    A commercial solutions like Pickl-It offers a wire-bail jar with glass lid, true rubber seal and food grade silicone grommet provide safe and guarantee an excellent seal for fermenting.

    • Sarah says

      Alan, you are correct in all your points. This is an incredibly creative and smart idea, but unfortunately, I don’t believe it’s an effective system at keeping out oxygen (which would defeat the purpose of fermenting for health) and neither does a popular blogger who got the anaerobic fermentation idea going strong. I wish this post would be updated so people aren’t misled, but I appreciate the original idea and intent behind it!

  20. says

    Thanks so much for this post. I bought an airlock at the local brewing store, but couldn’t figure out how to hook it up to the mason jar. I didn’t realize they sold grommets that would fit.

    • says

      Diane — Yes. Some veggies are more buoyant than others. If the veggies, fruits, or mixture won’t stay submerged beneath the brine, use a weight. A good one is often just a regular mouth jar lid. It fits well inside a wide-mouth jar. In the eCourse, someone just told me that she used a lemon slice to weight down the cucumbers for pickles. Also, you can use rocks — scrub and boil them to get them good and clean, then weight down a lid or cabbage leaf to hold everything down. People get very creative!

      • Alan says

        Use Rocks? bad idea… How do you know that the rock you chose doesn’t have elements you don’t want in your food. Even sterilized there could be lead, cadmium, arsenic, etc. in the rock, things that will more easily leach into your ferments in the acid environment.

  21. says

    I showed this to my husband, and even though he knew better he did not use a clamp. The drill bit caught the metal lid, spun it in his hand and sliced into his thumb and forefinger. Ouch–pretty deep cuts! Just a word of caution to those who might try it!

  22. says

    dear jen e i cannot find the grommets anywhere what hardware store did you buy them at i tried lowes , home depot , several ace hardwares and multiples of auto places . please let me know if you can help i live in so cal and you would think it would be easy to find . thank you very much

    • sharri stowers says

      forget the hardware store you can get all this online from a wine supply place and its dirt cheap…….if making or intending on making a dozen or more to use at one time buy a dozen of these to make the shipping cost effective…… i use midwest brewing its out of kansascity missouri….. my order was here in a couple of days and they sent a catalog which is terrific for all my future needs….shipping is cheap but make your purchase worthwhile…… these can be re-used and reused if you do this method

  23. Patrick McBride says

    I had to laugh, Before my salvation I used to brew my own beer. Airlocks?

    Down to the brew shop for 2 airlocks and rubber stoppers, over to the hardware store for a drill bit, home to the work bench with 2 lids from mason jars, a little drilling, a little grinding with my dremel, and a touch of sanding to smooth the edges. Only trashed one lid in the process. Wash it all, then prepare NT Ginger Carrots. Now watching, waiting and salivating :-)

    Thanks for the inspiration!

    Merry Christmas!


  24. Richard says

    I wonder if there are any alternatives to canning jar lids? They are made with BPA, and I’m doing everything I can to avoid that.

    • Vanessa says

      But does the BPA even come in contact with the food? I don’t think it’s a risk unless the food is soaking in it…

  25. Concerned citizen says

    Hey this is slightly off topic, but why the hell to you have a link to ron paul on the sidebar!??

    You do realize he has direct links to neo nazi groups, right?

    I’ve just finished a depressing read about the rise of neo nazis in Greece and thought I would think about something else like good organic food and veggie fermentation; I would have never expected such right-wing views to be connected to anything I associate with organic, local, and self-sufficient food movements.

    Have you read any of his policies? I hadn’t until now but the closest thing I could think of to his dark vision of a future was that scene from back to the future ( ) According to his own manifesto he wants to end amnesty status for refugees, abolish the welfare state, abolish what little restrictions there are on raping the planet for oil and gas, destroy women’s rights for abortion, and somehow remove birthright citizenship (don’t know how else you’re meant to gain citizenship, or is he saying himself and all other European decendents should be sent back to Europe?).

    Seriously, could somebody Please explain??

  26. says

    I’m the founder/moderator for Punk Domestics (, a community site for those of use obsessed with, er, interested in DIY food. It’s sort of like Tastespotting, but specific to the niche. I’d love for you to submit this to the site. Good stuff!

  27. Theresa Z. says

    The airlock directions call for a 3/4″ drill bit. Is that so? The photo doesn’t look like it.

    • says

      It’s supposed to be 3/8″! I emailed Jen (the author) and she said:

      “Yes, it must be 3/8 inch. (I haven’t made one in a long time, so I can’t say for sure, but it certainly makes sense to me!) If someone wanted to make sure they have the correct size hole and grommet, I suppose one could start out with the air lock, then find a grommet that fits nice and tight, then drill the according sized hole.”

  28. Jodi says


    I use the cylinder airlocks (they are easier to clean). They look like this, although they are much cheaper at a brewery supply/hobby shop as opposed to the Amazon prices (note the shipping):

    Also, I use tattler lids. They are BPA Free, dishwasher safe, and will not react with the food. Money very well spent!!


  29. Lori O'Leary says

    I just started reading your blog and this post is PERFECT timing. Learning how to ferment veggies is next on my list!

    Thank you for sharing and cheers from a fellow Ron Paul supporter 😉

  30. KLynn says

    Curious if you still use this system for your ferments? So many are screaming about the ineffectiveness of the mason jars with an airlock at sealing the jar -it is frustrating and confusing. Yes an expensive specially made jar sure would be nice but when we have about 5-6 different ferments going all the time, it is hard to justify that expense…

    • Phoebe says

      I am very anxious to see if anyone has any insight to this issue, as well. I have read that it’s not best to use Mason jars for anaerobic fermentation because they don’t seal well. I am having problems with my water kefir and am wondering if it’s because I use Mason jars. Does using this airlock in the lid help with the supposed air-sealing issue?

      Thanks for posting this. It’s nice to find a more affordable alternative to the commercial products.

  31. sharri stowers says

    the rubber grommets are referred to in my wine supply catalogs as bung holes or rubber bungs for fermenting buckets….and thats what all of my wine recipe books refer to them as as well….since they are from a wine supply store with a known purpose of using near a consumable product i am hoping i can assume they are food grade(i dunno but i am hoping) my source is midwest brewing supplies and they are on the internet ….i hope this helps anyone who is still searching for them with their technical name…but yes food grade tubing may also be used as long as it fits very snuggly into the hole that you drill out in the lid and sit a jar filled with water next to it and make sure to anchor the tubing inside of the plain water vessle securely..or it will pop to the top and out of the water when your fermenting veggie jars are burping so to speak… they have a wide variety of other supplies even for canning…once you place an order they send you a very nice detailed with pics catalog…shipping prices are really good and things are very cheap to buy

  32. says

    This is such a great idea! I am a homebrewer and thought of this as well, you were the first google search on air locked food fermentations.

  33. Joanna says

    I tried this and ended up just ripping through the lids. Any tips? I almost need to find a metal punch or something so it doesn’t trash the lids…

    • says

      Yes, it’s supposed to be 3/8″! I emailed Jen (the author) and she said:

      “Yes, it must be 3/8 inch. (I haven’t made one in a long time, so I can’t say for sure, but it certainly makes sense to me!) If someone wanted to make sure they have the correct size hole and grommet, I suppose one could start out with the air lock, then find a grommet that fits nice and tight, then drill the according sized hole.”

  34. says

    AAAAHHHHH!!!!! I just made a 1/2 gallon of fruit kimchee ina gallon fermenting bucket. I put an airlock in hole, and left it, but did not weight down the fruit & am now concerned the fruit might not have fermented properly. Any thoughts (before i poison myself & anyone else).

  35. Diana says

    I just bought a set of airlocks on ebay and they came with grommets. Also found the plastic lids someone already drilled holes in on ebay too. Then there are the silicone seals on ebay I bought those- I now have a set of eight on my jars. Also bought plastic lids without holes for after they are done fermenting.

    I also just found these jar weights on ebay – they look awesome. Hope to get those next month.

Leave a Reply

Your email address will not be published. Required fields are marked *

Notify me of followup comments via e-mail. You can also subscribe without commenting.