Do you need an airlock to ferment vegetables? Nope!

People often tell me that one needs an airlock to ferment vegetables. I say to that, Humbug! You can use an airlock if you like, but you do not need one to be successful at fermenting delicious, healthy, long keeping yummy things.

Ages back, I wrote about why the gospel of airlocks is mistaken. I'm not certain it fully meets the publishing standards for this site, as it comes across as a bit 'fact' heavy. So I'll give you the highlights and if you're interested, you can give the full version a read.


The conclusion is that you can use an airlock to your hearts content. It's not, however, necessary. In actual practice, the belief that using an airlock is the only way to get the full health benefits is based on some rather uncertain premises.

Do I need an airlock to make sauerkraut, kimchi, and other fermented foods?

There is a lot of debate out there as to whether or not you need to airlock your veggie-ferments. People are very passionate and sometimes a bit carried away. There is supporting evidence for both sides, but as you may have noticed I prefer the open vat method. In this post, I would like to give you a simple overview of the debate and tell you a bit about why I decided that the airlock is optional.

Open vat fermentations are basically a wide mouth container, some veg, some salt, some water, and possibly a starter culture. The veg is weighed down with an inner lid and a weight like a rock or bottle of water and covered with a towel to keep out flies and dust. The inner lid and weight insure that all the veg stay below the level of the brine, and thus out of contact with the air during the fermentation.

The top of the brine, however, is exposed to the air. Sure there is a slight layer of CO2 gas (fermentation farts) that settle on the undisturbed brine, which protects against some O2 (oxygen) contact, but how well it works is limited.

Airlock ferments have basically the same contents as the open vat, only an extra stage is taken to prevent the surface of the brine from touching oxygen. This will be something that allows the ferment farts (CO2) to escape without letting any gas back in. The Pickl-It system is the best example of this, but some people use those snap jars with the rubber rings like this one:

The idea is that airlock ferments allow more non-airloving invisible beasties to grow, and fewer airloving invisible beasties. This is, as far as I can tell, accurate. There is a lot of data and research on it. At the surface of the ferment, airloving invisible beasties penetrate into the brine. As time goes on, they penetrate further and further, sometimes turning your pickled cabbage into slush. It's far more complex than that, but in my usual fashion, I'm oversimplifying to make this idea more accessible to people new to the topic. If they are interested, they can look up the sciences. Wild Fermentation, The Art of Fermentation, and Nourishing Traditions are (in that order) excellent starting places for those who whish to learn more.

Air locks slow down this penetration of airloving invisible beasties into the brine. I don't dispute this.

What I have trouble believing is that we must do everything in our power to prevent this; that all fermentation must be done with an airlock. That's simply not true.

The airlock school of thought has some great science that talks about how many more good bacteria an airlock system can produce and how that the part of the brine that has exposure to O2 reduces the amount of these specific bacteria and grows air-friendly invisible beasties.

I've read the science, I'm not disputing any of it. It's good science!

However, it does rely on a few assumptions.

1. exposure to all air bacteria (aerobic) is harmful to us
2. if some anaerobic (living without air) bacteria (invisible beasties) for us is good, then way more of it is better
2.5 this also assumes that our body has an unlimited ability to use these bacteria.
3. That it is only the anaerobic bacteria that is good for us.
4. It is only the quantity of the bacteria that is good for us, not the ratio.

In the blog post, I examine these assumptions and show why they aren't as strong as they first appear.

I am slightly obsessed with the history of food and food preservation pre-refrigeration. Lacto-fermentation - the fancy name for what happens when you make sauerkraut and what we've been talking about this entire post - ... Lacto-fermentation has been used by people for a few thousand (probably a few ten-thousand) years, and during this time, it was almost always in an open vat kind of system. The 'airlocks' available until the 19th Century, were slightly porous, which allowed the food to breath. For example, a bladder (pre-20th Century clear-wrap) is very slightly porous and over time, 'breaths'.

So I look at history and I see that for most of human history people have been using open vat fermentation without any obvious ill effects. Especially none of the ill effects that some of the more enthusiastic pro-airlock followers declare will happen.

Looking at what we are learning about ecosystems (because what is a gut full of invisible beasties if not an ecosystem? - rhetorical question), human health, and history, it makes me wonder if looking only at the quantities is missing out on the really important aspect of fermenting (and how it relates to our health). Maybe there could be something to the ratios of invisible beasties - and possibly, just possibly, maybe using an airlock is detrimental to our health. This needs more study.

I know, shocking. And not, I think, going to win any popularity contests.

I'm confident no one here, would bash someone over the head with "the one right way to do something", this blog entry was written in response to something I kept seeing elsewhere on the internet that breaks my heart.

Person gets really enthusiastic about something. Say, making sauerkraut.
The go to the internet to learn more and hopefully gain momentum for their excitement.
They read that they can't do such and such without all this equipment and education. Or they go to a forum and are bashed over the head with all these people saying "you're stupid for wanting to try something new, go watch some TV"
They go watch some TV instead of making sauerkraut.

I came across this kind of situation again recently. Someone told me, "I want to make miso paste, but I don't have the right equipment to do it properly, so I didn't bother." What? Not the right equipment? You got a pot? Got a bowl? A spoon? A bucket? The person answers "yes" You have everything you need. "Yes, but it's not the proper equipment." It worked for the last thousand years, why would you need something different? "Because the internet..." Sigh.

For those of you on the receiving end of those well-meaning lectures as to why you must only ever always use an airlock when fermenting. Be strong. These people have a lot of science and aren't afraid to use it. They are also very intelligent and vocal. It's hard to stand against that, especially when all you have is an unarticulated feeling in your gut that maybe something they say isn't right, but you can't find any fault in their logic or science.

What you can do is look a history. We've been successfully fermenting without airlocks for thousands of years. And only using airlocks in earnest, in popular culture for the last 10 years.

If you feel an airlock helps you, then go for it!

If you don't want to use an airlock, that's fine too!

If you're new to fermenting, then go for it with what you have on hand!

If you want to tell people the one true way to do something, then go somewhere else.

I agree. I do both regularly. I think they each have advantages.
John S
PDX OR

great post ... thank you ...

i wonder how many of the articles/posts on the internet that say you ll need an airlock are from people who are selling these airlocks...

Tobias Ber wrote:great post ... thank you ...

i wonder how many of the articles/posts on the internet that say you ll need an airlock are from people who are selling these airlocks...

I wondered that too at first. There is certainly that element to it.

I think it's gained so much momentum, that people read a book, they tell their friends about the one right way to do it, then the idea continues to grow until no one remembers there was a time one could ferment in open vats.

on most of my covered ferments I use a plastic lid on a glass jar. any excess pressure builds up and self burps but the lid doesn't really let anything back in. I have done sauerkraut with no lid before.

Right! We have made several hundred liters of kimchi and Ladakhi pickle with no airlock, and it always comes out delicious, and stays good for at least 7 months in cool storage. We make huge amounts every October because there will be no fresh veggies available until April or May except from our root cellar and greenhouses.

We reuse 15-liter cooking-oil containers (food-safe) with wide-mouth screw tops, not airtight. We don't even weigh down the top of the veg or anything, and it stays perfect, every time. We just pack it in as hard as we can, leave some headroom for juice bubbling up, put the top on, and stand it on a tray in a sunny window. For the first several days, liquid oozes up and out. When it settles down after a week or so, we store them in the cool root cellar for the rest of winter.

My experience:
-- Airlock is unnecessary for a salted, cabbage-dominated ferment.
-- Ferments made with mostly cabbage-family plants and enough salt are always successful.
-- Sunlight or dark has no effect. It is just cultural tradition one way or the other, and feelings run strong.
-- Keep it in the warm for about a week until it's sour and tasty, and the bubbling up has slowed. Then don't forget to shift it to cool storage, so it will stay good for months. If you keep it in the warm place too long, it can go oversour.
-- I can testify that garlic, oil, and/or specific spices make no difference to successful fermentation and preservation.

I think it's our consumer culture. The answer to everything is a purchase of some sort.

I'm not immune myself! I remember when I read about barefoot running and saw the brilliance of the unencumbered foot, with the arch serving as a muscular spring. Perhaps my foot pain was better served by more time without arch supports instead of expensive custom orthotics!

My first response was . . . to buy a pair of "toe shoes," those cute shoe-like products that fit your foot more like a glove. Of course what fixed my foot pain was miles and miles on the treadmill in just socks, I didn't need the toe shoes. I do like them for other things, but I didn't really need to buy them.

Same thing with airlocks. They can be helpful, I think they are pretty essential for making alcoholic drinks and it's fun to see the bubbles coming out, but they are in no way necessary.

My first fermentation read was Wild Fermentation. I gave sauerkraut a go in a glass jar with a freezer bag full of brine as a weight on top of the cabbage. Worked well and am now hooked. I've tried an airlock system. That works too. My preferred jar is a clip lock type. I don't bother weighing the contents down. If the top layer is icky I just scrape it off. I find my nose is a good judge of the state of the ferment: sour or beery smells = yummy, rotten smells = toss it out!

shaking or stirring the contents from time to time will help to get the floating particles washed over with the brine. this will help prevent rot/mold.

While you don't need an airlock I think it's important to exclude external air(carrying yeasts and fungus spores) from entering before the ferment takes hold fully.
Most containers do a fine job of this already as the ferment is producing heavier than air CO2 that sits on top and forms a barrier of sorts. Warm temperatures get a good ferment going, producing lots of CO2 and driving off external infiltration of contaminants.
I've chosen to use a tall, narrow container. This allows a good column of CO2 gas above the ferment.
A simple flexible cover (silicone bowl) allows excess pressure out, no contaminants back in.
In my experience, anything floating on the surface is asking for trouble. My #1 rule - keep everything submerged in brine at all times.

I agree you do not need an "airlock" but everyone here posting is using a form of an "Airlock"
Whether it is a cap on your re-used jug or a lid on your Fido or a silicone bowl on your beaker..... you are using a device that allows CO2 to build up and most agree that CO2 helps keep down failures.
If a person offers to sell you an airlock as a convenience and it offers some relief from burping many containers.... then that is your choice to go for that convenience or not. For him to tell you that you need his airlock is false advertising. And for under $1.50 a standard winemaking 3 piece airlock can be added to your lid. So it is not going to make a person rich selling you a little convenience. Same goes for the seller who offers to sell you a glass weight to hold your stuff under the brine. It is your choice to buy or not. If he tells you that you need it... that is false advertising. You can use whatever you want.
Keeping a lid on your ferment I would call a needed thing. It is your choice to use cheesecloth, a metal lid or plastic or whatever. Open fermentation vats are still used today. I would think you have enough smarts to know when to use cheesecloth or not depending on how many gnats and flies are in your area. The choice is yours. BUT don't let a person shame you into NOT using an airlock if you see fit to incorporate that into your fermenting system
While on the subject of "airlocks" no one mentioned a popular one we used to use which is a child's balloon. Great way to tell how much CO2 your ferment is putting out and can help you tell when your ferment is nearing the end of it's cycle.

Luckily, no one on this forum would attempt to shame anyone else to use or not use an airlock, as it would break the Be Nice rule. It's nice to have alternatives, so that each individual can make their choice.

It was mentioned that airlocks reduce the chance of failure, my experience is this is true with starter cultures ( aka, mothers or store bought cultures) and sterilized ferments, but I've never had this with wild ferments. The air contains the same microbes as are in the skin of the veggies we rely on to start our fermentation. Some people like to keep these out, I don't see the need for short term ferments of less than a month or two.

Someone said that we all use an airlock. Really? We must be using different definitions of airlock. Here's my current chili sauce batch. Jar open, smaller jar inside to prevent garlic from floating, a light towel to keep the dust out. I'm not seeing the airlock, as I won't be closing the lid until the ferment is in finished burping and into storage.

Yes I see you are an open container person. You are indeed correct . I generalized to much and you caught me.
The people I refered to used a cap, a lid and a silicone bowl. Those are indeed a form of airlock. In that same manner a cloth laid over an open crock acts as an airlock as CO2 is heavier than O2 and will settle under the cloth to an extent as it is heavier. This same principal is taught in most chemical plants and refineries as well.
And yes it seems the general theme of the thread is that people are being led into not using an airlock and I took the initiative to stand up for the use of the airlock as the general drift of the thread did indeed leave a reader thinking it was a waste of time and $1.50 or so.
A mother like in kombucha or vinegar requires O2. If doing an F2 ferment you will not have the scoby or mother in the container and then it becomes an anerobic ferment and would require an airlock or lid. An airlock like a cloth would not be suitable. I am also sure the mother of vinegar is the same as one way to rapidly produce said is to pump O2 into it. The result is vinegar in 24 hours at times.
Another reason for an airlock / lid/ covering is that some places like here has lots of gnats and flies that are attracted to the smell of fermenting foods.

I'm confident that shaming isn't the intent.

If you are seeking a bit more balance, how about starting a thread celebrating airlocks. Airlocks are often useful and even I use them from time to time. I especially like them for long term ferments (more than 2 months). You could start the thread by describing some of the different types of airlocks and see where it goes from there. That would give people access to more information and an opportunity to choose which style works for them.

I started this thread because so many people tell me "I can't ferment veggies, I don't have an airlock", which made me sad. Of course they can. I want them to go and try it with what they have in their kitchen, see what it's like, then experiment to decide if they like an airlock or not or sometimes.

I agree and apologize if it appeared I was serving my own interest. Starting another thread would not be possible as my title would be the same as yours It is how I feel. The only thing I would do would be add the word "commercial" in front of airlock.

It is important that people know they do not need one! Without a doubt! I think your thread pretty well covers the topic. I was just trying to add not so much to your initial post but to the general drift the replys were seeming to take. Your post was indeed fair.

With every successful or failed ferment we learn. The first thing is what one looks like and the second is what one smells like. I have had failures using airlocks as well as without one. I am to this day guilty of throwing together a ferment with no weight or commercial airlock. I have had a few bent lids but no explosion though I do know it could happen. Leaving my mason jar lid cracked serves its purpose and common sense lets me know when I can tighten it more as the ferment slows. If i had started fermenting using all the conveniences, I would maybe not have learned that valuable piece of information.

Again I apologize if I was taken the wrong way. My interests are the same as yours. I wish everyone to try fermenting for what ever reason they want to. I think it should be taught in school along with gardening and canning as well.

Sincerely,
Mike

How about this for a title: In celebration of airlocks - why I love using an airlock for fermenting vegetables. Positive, says what's it's about, friendly and invites clicks.

I think you sell an airlock product (looks really good, by the way). Please include a link to it in the post, just be sure to include other kinds of airlocks as well, so it doesn't come across as too much self-promotion and get shuffled off to the Blatant Advertizing section by an enthusiastic staff member who didn't see this conversation.

It would be a great thread and wonderful resource for people to learn about airlocks. I think you're just the person to start a thread like that.

Nukadoko (Fermented Rice Bran Bed) for Pickling

This is a very old and well understood form of fermenting.
It is clearly not air tight.

alex Keenan wrote:Nukadoko (Fermented Rice Bran Bed) for Pickling

This is a very old and well understood form of fermenting.
It is clearly not air tight.

Yes this does not require a commercial airlock for sure I think this type fermenting is over my head and out of my comfort zone to personally attempt

Mike Harmon wrote:

alex Keenan wrote:Nukadoko (Fermented Rice Bran Bed) for Pickling

This is a very old and well understood form of fermenting.
It is clearly not air tight.

Yes this does not require a commercial airlock for sure I think this type fermenting is over my head and out of my comfort zone to personally attempt

You purchase you rice bran online.
You mix salt, water, rice bran per instructions.
You add some vegies per instructions.
Once it gets fermenting it is little work. The main job is stiring the bran.
You can get totally different taste than crock fermenting.
http://www.gardenbetty.com/2014/08/how-to-make-nukadoko-fermented-rice-bran-bed-for-pickling/


I have a german crock and will be starting another rice bran bed this fall in a tub.

In defense of airlocks, I have never lost a ferment when I have had an airlock on it. I have lost ferments, particularly my trouble-fraught attempts at cucumber pickles, only when I was not using an airlock. I fermented sauerkraut, ginger carrots, and radishes without airlocks quite successfully. But, even knowing that I can ferment without an airlock, I have gone to always using an airlock. If I was working with bigger batches, investing in old-school crocks would make more sense, but a half-gallon mason jar is usually as much as I want in any one batch. Except for salsa. Can anyone ever have too much lactofermented salsa?

This rather nifty review of fermentation devices supports R's view that airlocks are not needed (setting preferences aside):  https://fermentersclub.com/smackdown/.



At the link above is a video playlist of the comparison steps and the results.

I've used the Masontops silicone toppers ("pickle pipes") and I really like them for a number of reasons - the main one is that I'm cheap and lazy. (Hm, did I learn that from Paul, or is that a reason why we're a good match? )

Jocelyn, I was intrigued by the glass weights that the Pickle Pipes people sell, so ended up getting a few lids as well. The glass weights are really nice and should last indefinitely.  

After three years of failed attempts at lactofermenting cucumber pickles, I gave it one last go with the glass weight and a PicklePipe lid.  Presto.   No disaster in the form of various unknown kinds of mold and slime.  Actual cucumber pickles.   FINALLY.   And pretty tasty, too!

Congratulations!  My cucumber vines have not done so well, I think they've gotten overly thirsty too many times to be thriving.  I should think about getting some cukes at the market. . . or see if my friends at the Columbia Ecovillage have a surplus.

Woohoo! Go K! So glad the Pickle Pebbles and Pickle Pipes worked for you! (I also have their Pickle Packer from their Kickstarter - so fun to say all three! -and later this fall my rewards include a webinar with Sandor Katz!)

You mentioned slime and mold. A lot of folks scrape that off the top and keep the ferment, though that's hard for me to do. In the video I shared, if I recall, I think that happen to a batch and then the blind taste testers didn't like its flavor.

Julia, good luck with your or finding cukes! We still have some summer left!

You mentioned slime and mold. A lot of folks scrape that off the top and keep the ferment, though that's hard for me to do. In the video I shared, if I recall, I think that happen to a batch and then the blind taste testers didn't like its flavor.  

In the unlikely event that the world totally collapses, I'd be willing to do that.  For now, unless it was something solid like miso where the mold could cleanly be scraped off, nope, nope, nope.  Life is too short to be eating mold. Except on cheese. Then it's cool.  

I do think the glass weights made a big difference in keeping the tips of anything from surfacing above the brine.  I think even having that 1/4" or 1/2" creep above the surface now and then is enough to spoil a batch.

K Putnam wrote:
I do think the glass weights made a big difference in keeping the tips of anything from surfacing above the brine.  I think even having that 1/4" or 1/2" creep above the surface now and then is enough to spoil a batch.

One other stacking functions type hack I've used is to use glass tealight candle holders as a weight in wide mouth jars. I have three that look sorta like this, though I think mine are a flatter disk shape and less bowl-like:


(Image source:  uber cheap tealights at Target - no diameter listed.)

My tealight holders and the ones I've Googled now were/are so cheap though (cheaper than the Pickle Pebbles!) that I do wonder if they might have lead in the glass. I'm thinking an unheated ferment might not be a concern for that, though I don't really know and I feel far better using the Pickle Pebbles.

The Pickle Pebbles (Amazon affiliate link) list as 2 1/4 " diameter while most of the cheap glass tealights I could find on Amazon (again too bowl-like to work as well as mine) list as 3" diameter.

Just a thought since candle holders are usually plentiful at thrift stores and such.

Jocelyn...great alternative!  In a pinch, I have used shot glasses...ubiquitous, and food-safe.

I have some river stones that I picked up specifically for this. They get a good cleaning every so often when I make beer or something that needs to be more specifically cleaned. I also have some tiny silicone molds for--- teeny bundt cakes? not sure what they're for, the kid bought them to make soap and I stole a few. They are flexible but work well on top of pickles to push them under, against the lid.
In another pinch, a plastic bag filled with water (I always think of goldfish in a bag....) works well too.

I've only done some fermenting and use the silicone tops with a glass weight. But I only have so many, so I sometimes just use a smaller jam jar filled with water and covered in cloth, and that works well too. I'm hoping to try more this year, since we're getting pretty good with the garden plot.

I've bought just about every kind of fermenter lid there is for a mason jar. I recently was offered some of these to review, and I think I like them more than any others I've tried because they don't take up extra height on a shelf and work well. I just love mason jars. The airlocks I've bought sit unused in a drawer. They are just too much of a hassle. I think something like this is the best of both worlds.

https://www.amazon.com/dp/B09NPGLRN3

r ranson wrote:Luckily, no one on this forum would attempt to shame anyone else to use or not use an airlock, as it would break the Be Nice rule.  It's nice to have alternatives, so that each individual can make their choice.

It was mentioned that airlocks reduce the chance of failure, my experience is this is true with starter cultures ( aka, mothers or store bought cultures) and sterilized ferments, but I've never had this with wild ferments.  The air contains the same microbes as are in the skin of the veggies we rely on to start our fermentation.  Some people like to keep these out, I don't see the need for short term ferments of less than a month or two.

Someone said that we all use an airlock.  Really?  We must be using different definitions of airlock.  Here's my current chili sauce batch.  Jar open, smaller jar inside to prevent garlic from floating, a light towel to keep the dust out.  I'm not seeing the airlock, as I won't be closing the lid until the ferment is in finished burping and into storage.

COOL.  can you elaborate on your chili sauce?  do you ferment the garlic cloves and fresh? chilis, and then scoop them out as needed when you want to make sauce?  or do you ferment them and then blend them together, and then keep fermenting in sauce form?  

I did a ferment in a glass peanut butter jar which has a gasket ring in the lid.  Used a stone from the top of the wood stove figuring it was sterilized by the heat. Figured if the lid was too tight it would bulge to remind me to burp it.  Keeping it on the counter top so if I see bubbles trapped along the sides I tap the jar on the counter to bring them to the surface.  Have not had to loosen the lid. What should fermented kale be called?