Do I Have to Use a Special Vessel To Ferment In?

Do I have to use a special vessel to ferment?

No.  Of course not.

I know this answer will surprise many of you since I kind of took a hard line on fermenting anaerobically last year.  But here is the deal, I’m not going to tell anyone they HAVE to do anything.  I am going to recommend to you what I think is the best way but that’s not me saying you absolutely have to do it my way.

I started out fermenting in mason jars with whey like shown in the book Nourishing Traditions.  It worked for me and I liked the results.  I began researching how fermentation was done traditionally and found a whole lotta different ways.  Many of these ways tried their darndest to make the conditions anaerobic, some tried not quite as hard.  I decided to make the switch to an anaerobic jar (the kind listed under Fido’s with an Airlock) and ditched the whey and loved the results.  My ferments were good before but now they were a whole ‘nother level of awesome.  This is the only way I ferment now.

The purpose of this post is to go through a few different methods and give you my thoughts on them.  Take it or leave it, it’s just my opinion.  I’ll put them in order of what I think is worst to best.  This is JUST my opinion.  To really know how well these methods compare, one would have to test all of them to determine how many CFU’s they contain and what strains of bacteria and yeast are growing.  Both things I just cannot do.

To avoid anyone accusing me of making money off of this by promoting only one product, I’m not going to put any affiliate links in this post or even name names.  If you want to know, just email me:

To be completely honest, I don’t have an affiliate account with any airlock or fermentation crock company besides Cultures For Health.  Purchasing a fermentation vessel through them from a link on my website is the only time I would a commission off of a fermentation vessel.

Crock Covered with a Cloth

I had the opportunity to sit down with my German grandma this past fall and talk about sauerkraut.  She has made way more sauerkraut in her life than I ever have and she has never heard of the term anaerobic fermenation.  She used a crock, weighed the cabbage down with a heavy plate and covered it with a cloth.  The one way I highly recommend people not do.  Is it anaerobic?  Not really.  Keeping the cabbage submerged under the brine reduces it’s contact with air but through diffusion, it can get to the cabbage.  But the thing I fear most with this type of ferment is the suggestion to just scoop off the mold that will grow on the top and keep going.

A hundred years ago when our ancestors used this method, the time was very different.  People ate real food.  People were not on antibiotics from infanthood on.  People were not exposed to toxins like we are today.  They weren’t taking medicines like we do now.  Their guts, for the most part, were healthy.  Scooping mold off the top of a ferment was probably fine at the time.  Their strong immune systems and gut flora could deal with any bad things that might might get into the ferment.  If mold is growing on top, mold tendrils are reaching down into the ferment.  It’s impossible to scoop it all off.  We don’t live in that same world.  Many people (I would guess nearly everyone) has some level of gut dysbiosis.  Some might be able to handle but not everyone can.  People do get sick from ferments done improperly.

This is why I recommend people not use this method if they are seriously trying to heal gut issues.  If your strong as an ox and don’t care about a little mold, I’m not stopping you.

Bag of Water On Top of the Ferment

Fill a bag with water and plop it on top of your ferment to keep it away from air.

The biggest issue I have with this method is the plastic being in contact with the ferment.  Acids break down plastic and I don’t want to eat plastic yuckiness.

Air can creep down the sides of the plastic bag through the creases so I would not label this a good anaerobic solution.  This method is prone to mold too.  If air can get in, yucky things can grow.

Mason Jar

There are two groups of thought here.  Loosely covered and tightly covered but burped daily.

Loosely covered fits into the same category as a crock covered with a cloth for me.  Again, especially if you have gut issues, I wouldn’t do this.

Tightly covered mason jar.  It’s a step up and actually quite a big step up but still not ideal.  To keep the jar from exploding, you need to release the pressure daily by opening the jar.  This lets the gases out but also lets air in.

So is it horrible.  Meh, I wouldn’t say horrible but I wouldn’t say good.  It seems to do an ok job keeping most of the air out and you’ll have less of a chance of mold happening than if you used an open crock.  That’s why I say it’s a step up from an open crock with a cloth covering.  If you have to worry about the jar exploding, it’s pretty tight.  Plus the pressure inside is greater than the pressure outside.  If air was to make an exchange, it would be the outside air leaking out and not so much the other way around.

Storing in a mason jar is a different story.  Once the fermentation activity dies down, there won’t be pressure inside pushing out and air can get in.  Oxidation in storage is very likely and has happened to me.

I used this method for quite a long time and never saw mold grow.  But I live in a cool climate.  I suspect a hotter climate might have more mold issues with this method.

If you still really want to do this method, I would suggest using a vegetable starter.

Olive Oil Topped

I wrote about this method here: Olive Oil Topped Ferment

I have mixed feelings on this method.  It is a traditional method and it does seal the air out but using enough olive oil over the top can get spendy after a while and there is a risk that botulism can grow in the oil.  I’ve never heard of an instance of this happening but that doesn’t mean it can’t.  So this one, I’ll leave up to you to decide if it’s worth the risk.

Mason Jar Airlock Methods

There are a few options under this banner but I think all of them are far superior to the 3 methods I addressed.  My scale would look something like this form worst to best:

open air–>tight mason jar————————————->olive oil—>airlocks—>hermetically sealed

My first venture into airlocks was a major flop.  This was actually my first ferment to go wrong.  Way wrong.  The problem with the airlock I first used was the fact that it was a plastic lid with no gasket.  Might as well just use nothing. Plastic isn’t strong enough to hold down the lid tight enough and without a gasket, air can go in pretty freely.

Most mason jar airlocks on the market are better than this first one I bought.  Many do contain a decent gasket.  If you want to go with this method, make sure the gasket is not a thin tiny one but fairly thick.  The gasket on the metal lids that come with mason jars isn’t enough in my opinion to make it truly anaerobic.

Also, read my post on some of the plastic caps.  I don’t feel comfortable enough with plastic to use it with ferments.  DIY Airlock Update.

One argument I hear against this type of airlock is the fact that the metal rings or plastic cap just don’t bear down on the gasket enough to be airtight.  Honestly, I’m not so sure it’s as big of a deal as I once thought.  During fermentation, gasses are produced and push up and out.  There is more pressure inside the container than outside so I just don’t see air working it’s way it.  Once the fermentation activity slows down and there isn’t as much pressure inside the jar, there might be more of a chance of air getting in.

Fido Jars

This is another method I have mixed feelings about.  You can read my thoughts here: Fermenting in Fidos.  Basically, I’m unsure of the affect the trapped gasses have on a ferment.  It’s enough pressure to push the CO2 into the ferment making it quite fizzy.  The verdict is still out on this method.  My suggestion if you want to try it is to very slightly lift the lever to release the gasses at least once a day.  Not enough to let air in but enough to let air out.

Synthetic cork with an airlock

If you don’t have a latex allergy, this could be an excellent option.  A large synthetic cork fits nicely inside a regular mouth mason jar.  Fitted with an airlock, you’re good to go.

Here is a great article about how to make one yourself,

Harsch Crock

A Harsch Crock (or similar fermenting crock), is a large clay pot with a lid that sets in a moat filled with water.  The water seals the jar so no air gets in but air escapes easily through the water.  This method is excellent if you want to make large batches but not so great for small batches.  They are also very expensive.

Fidos with an Airlock

This is the only method I use.  That’s how strongly I feel about it.  You can buy these or you can make them.

I’ve been hesitant to tell people to make their own because of the risk of glass dust getting into your ferment or injuring yourself by drilling glass but after talking with many different people experienced in glass drilling, I don’t feel it’s all that bad.  Can you get sick from consuming glass dust?  Sure but it would take a lot.  I don’t normally quote Snopes because I don’t think they are always right but this is a time where I believe they get it right.

Is drilling glass risky?  Not if you do it correctly.  Use a diamond edge drill and water and you should be good to go.  Here is a great tutorial on it

If you do think it’s too risky, don’t want to eat glass dust, don’t want to bother with drilling, you can buy them pre-drilled.  The company that sells them uses a special method of drilling and polishing to make sure glass dust isn’t a problem.

I do feel this method is the best method.  Fido jars are certified hermetically sealed which means no air gets in.  Adding the airlock takes away the concern that trapped gasses might have a negative effect on ferments.  You can read more about why I think this method is the best here: Anaerobic Fermentation.  Bottom line, if you have major gut issues that you are trying to heal, seriously consider using this method.  You don’t want to mess around with methods that might work.  Stick with a method that does work.

What Method Should You Use

Don’t take my word for it. Do your own research and figure out what is best for you.  While I do have my opinion on what is the best way, I’m not going to tell anyone they HAVE to do it my way.  Giving information about different methods and why one way might be better isn’t telling people they have to do it that way.

ETA: Other factors like where you live will affect your ferments.  Places that are more prone to mold will need to care extra care to use an anaerobic container.

Please, please, please don’t be scared to ferment.  You’ll know right away if a method failed or succeeded.  If there is mold or it stinks, it’s no good.  If it looks, smells and tastes great and has no mold, it’s good.  On the microscopic level, an extra good anaerobic jar is probably superior but a less than perfect jar might just end up with less lactic acid bacteria.  If you have gut dysbiosis, this might be the difference between healing in a matter of months to a matter of years.  If you are scared, stick with the more tried and true anaerobic jars.

Part of Traditional Tuesday, Fat Tuesday

**This post may contain affiliate links. Purchasing from these links helps support Pickle Me Too, allowing me to post and store all of my free recipes. Thank you!**

13 comments to Do I Have to Use a Special Vessel To Ferment In?

  • Marya

    Thank you!!! This is what I needed to know!

  • Thank you, very useful. I enjoyed it as well.

  • Thanks for this post! It’s very balanced, sensible, and informative. Thank you!

  • Guro

    Great post:-) What do you think about the Pickle-pro lid? Would you be concerned about the plastic?

  • Where do you get a Fido with Airlock? I wish you had included links and am happy to support great websites through affiliate links for their hard work 🙂

    I have always done sealed mason jars for my ferments, but would love to try a different way if it’s better. The only thing I use a cloth on is Kombucha because I was told that it’s not supposed to be anaerobic.

    • Thank you for your support! I just wish everyone felt that way. I’ve been accused of promoting only one jar to make money which I find hilarious because it’s the one jar that doesn’t have an affiliate program. You’ll only get honest opinions out of me 🙂

      The fido with an airlock is from

      And yes, kombucha and vinegar do need air. Let those babies breathe!

  • PJ did pressure tests on the plain fido jars. They withstood 30 pounds of pressure just fine, before blowing the contents out the top.
    No breaking or shattering. Pretty sure a ferment cannot come close to that kind of pressure.

    • Yep, I’m not concerned about the fido exploding. I’ve seen them off-gas myself. The problem I see with fidos is the fact that they don’t off-gas easily. There is quite a lot of pressure in there, enough to throw the lid back when opened and enough to push CO2 into the ferment to make the veggies carbonated (which is actually kind cool, fizzy dilly beans rock). I just don’t know the effect this pressure has on a ferment. I would love to see a comparison of LAB content of a fido ferment vs a ferment allowed to off-gas easily but I personally don’t have the funds to have them analyzed. Maybe someday…

  • Hi Melanie –

    Thank you for the great information. I just read the Body Ecology Diet and immediately felt that fermented foods are what I need to help me overcome candida. After watching some videos on You Tube, I had the impression that all I needed were some mason jars and culture starter.

    So I ran out and bought my supplies. My first ferments (cabbage) gave me awful gas. Following the (bad) advice of many, I only let it ferment for 5 days before eating it.

    Your website helped me realize that there is a good way to ferment and there is a much better way. I just ordered a set of Pickl-It jars along with a nice set of Fido jars. I can’t wait to get started the right way!

    One question – why is that that store-bought ferments like Wild Brine and Rejuvenate Foods taste so differently from one another and each so different from home-made ferments? Isn’t the process the same? I really love the briny flavor of Wild Brine and want my own ferments to have that tang. How can I control that?

    Thank you again for your excellent information!

    • I’m so glad my blog has been such a help to you. That’s exactly how I think. Ferments are great but why not make them the best you can.

      I’m not familiar with either of those brands. I live in a fairly small town and don’t see any of the commercial brands here 🙁 They might have a bit of a different process like they might age their ferments for different lengths. They might also use a different amount of salt. More tang comes with time. I like my sauerkraut sour so I wait at least 3 months before consuming. I have sauerkraut that’s almost a year old now and is super tangy! The same goes for pickles. A pickle that’s only 1-2 weeks old will be very fresh tasting where a pickle that is a few months old will be a full sour pickle. The same recipe will taste different stages.

  • Mom2gaggle

    I have the ability to vaccuum pack the mason jars with the metal lids. Would this be good or a disaster? Just started my first jar today and just have a screw lid on it. Now I am thinking I jumped in a little too quickly!


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