Sauerkraut Survivor – Final Report

Although I will be reporting how the jars do in the fridge, I do consider this my Final Report.

Let me remind you why I did Sauerkraut Survivor in the first place- there was a lot of hullabaloo over which jars are safe for fermenting and which are not. There was a blogger or two who insisted the Pickl-It was the only safe jar to use – using mason jars was akin to eating junk food. Then there were those who insisted mason jars were safe and never got mold in them. And those who admitted to getting mold regularly, but skimming and tossing was not harmful.

Who to believe? The only way for me personally to know, was to do an experiment myself.

Before starting the line-up of 18 jars, I wrote The Science Behind Sauerkraut Fermentation which is based on my crash-course research when I was on a mission to find the truth. I learned a lot in those two weeks of research! I was convinced oxygen was the enemy – but how much was too much? I had to find out – and Sauerkraut Survivor was born.

The day before we packed the jars, we tested the seals. We proved mason jar lids do create a tight seal after all – and so does a lowly salsa jar. We also learned the Fido (with gasket that acts as an airlock) and Pickl-It (Fido with an extra airlock) are not airtight, but do allow for excess CO2 to be released if needed via the gasket.

Day 1 shows what all the jars looked like after the jars were packed. Baseline pH, glucose, and brine samples were taken. 24 hours later photos and samples were taken and recorded. Day 3 showed the beginning of the gaseous stage, which continued though days 4, 5 and 6. CO2 was dying down by Day 7. I had to purge some jars on Day 10, as they were getting moldy, or brine was no longer covering the top due to the pressure from tight seals and brine pushing out the test ports. Day 14 shows the second stage of the ferment. Day 21 shows by the drop in pH, glucose numbers, and brine samples that we are just about done. I transferred some jars to the fridge on Day 23 since the brine was starting to fall back down in the cabbage where the cracks were from the heaving (gaseous stage) and I didn’t want them spoiling. And, finally, you have the Day 28 results for when I opened the Harsch and Fido for the first time ever, and the Pickl-It for the first time since Day 7. Brine sample was reviewed using this AmScope microscope. Photos were taken on the microscope with this AmScope camera.

My goal in this experiment was to see which jars kept out mold and yeast. Did I really need an expensive jar to do the trick? Or was there a more affordable way?

After this experience there are jars I am comfortable with using, after having tested them, and jars I wouldn’t use. And then there are jars I would use if I had to, IF.

I also confirmed this: the longer you leave your sauerkraut out, the more LABs you get. Putting them in the fridge on Day 3 is a popular method, but one I don’t intend to follow. The pH hasn’t dropped enough to keep spoilage away, and the first stage bacteria have barely begun.


Before I post my final results, I just wanted to personally thank all of you who have been so supportive of my research. It has been a lot of fun to go on this journey with you.

One of you mentioned it was like watching a horse race in slow motion. I agreed!

Another said it was “like watching a National Geographic episode unfold, complete with the soothing deep voice of the narrator.”

I was fondly called a geek – and a nerd! Yay for geeks and nerds! And I think I saw the works “sauerkraut rockstar” – that cracked me up :)

I also want to thank those of you who gave financially. Many of the supplies purchased for testing were mostly covered due to the generosity of:

Jar #12, Lacto-fermentation Air-Lock System, was generously donated by the manufacturer, Cooking God’s Way.

Jar #13, Pickle Pro, was generously donated by the manufacturer, Homesteader’s Supply.

Jar #14, Pickl-It, was purchased through the generosity of GNOWFGLINS.

Jar #15, Harsch crock, was purchased by the generous donations largely from Homesteader’s Supply along with with GAPS Diet Journey, Hybrid Rasta Mama, and Dishrag Diaries.

I could not have done this without your generosity! THANK YOU!

So…are mason jar ferments safe? You be the judge…

I fully expect everyone knows I am not a scientist. I did this experiment for my own personal research so I would know what jars are safe to use for fermenting. My conclusions are my own – you’re welcome to take them or leave them! :D Here they are…

Jar 1 (Cheesecloth)

I don’t think I need to go into why this jar didn’t make it :) This was booted from the line-up on Day 10.

Jar 2 (Olive Oil)

This jar is effective at keeping the oxygen out, although I probably wouldn’t use it unless I lost my lids. If you’re worried about dust on the oil – loosely cover it. it’s not easy to remove the oil when you’re ready to eat it, but you could always just mix it in. Full disclosure: a yeast was detected which seems to be the helpful yeast, Saccharomyces cerevisiae. Since I am not a scientist I am waiting for confirmation. At 28 days the LABs were mature and moderately populated.

Jar 3 (Baggy with Water)

I really don’t recommend this jar. I found it near impossible to prevent cabbage from being trapped between the baggy and the glass. Those pieces spoiled. I would only recommend this jar if you are sure you don’t have any cabbage pieces trapped.

Jar 4 (Cabbage Leaf held down by small jar)

You might be able to get away with this method if you don’t leave it out more than a few days. But to properly ferment the ‘kraut, you want to leave it out around 4 weeks. Of course by then the cabbage rots and infects the sauerkraut. Ew! I can’t recommend this jar.

Jar 5 (Cabbage Leaf, Shot Glass, White Lid)

This jar did well on all days, except Day 14 when spoilage was detected in the brine. I believe it is due to the brine not covering the cabbage entirely. No spoilage was detected on the cabbage when I moved it to the fridge on Day 23, though. I would only recommend this method if you are sure the brine stays over the cabbage.

Jar 6 (White Lid)

Low levels of spoilage was detected on Day 21. Until then, this jar did well and had nice LABs. I can’t recommend this jar (unless you use the added protection of a baggy – Jar #7).

Jar 7 (White Lid with Baggy)

This jar has a leg up due to the baggy and is effective at keeping out oxygen. LABs from Day 23 (before placed in fridge) showed really great LAB density. I would use this jar.

Jar 8 (White Lid with Airlock)

I am not seeing much of a difference between jars 7 and 8. If you’re lazy, just go with the baggy and skip the airlock installation. :) I do recommend this jar.

Jar 9 (Metal Lid)

The metal lid and band makes for a tighter seal than the white lid. LABs for this jar (and jar #10) have always been better (longer and more populated) than the white-lidded jars. LABs on Day 23 were incredibly active and populated. However, I must tell you that I had a glass tube installed in this lid so I could access the brine for sampling. This is where the pressure was released in this jar. If you use the lid and ring tight without an airlock you could risk a bruise from the lid popping off – or worse. Screwing the ring on loosely could allow for oxygen. Be safe and use an airlock (Jar #10).

Jar 10 (Metal Lid with Airlock)

As I stated for Jar 9, this metal lid and band makes for a tighter seal than the white lid. LABs for this jar (and jar #9) have always been better (longer and more populated) than the white-lidded jars. I would use this jar.

Jar 11 (Cork with Airlock)

The cork goes into the jar quite a ways, not leaving much room for the brine to go anywhere – but out. I would try this jar again without filling the jar so full. I had to dispose of this jar on Day 10 because there was no brine left. I am not sure, at this point, if I would use this jar or not, but am willing to try it again.

Jar 12 (Lacto-fermentation Air-Lock System generously donated by Cooking God’s Way)

This set-up is a white lid with a gasket to make for a tight seal. This jar has always done well. LABs were super dense when I transferred this jar to my fridge on Day 23. I would use this jar, and the price is right.

Jar 13 (Pickle Pro generously donated by Homesteader’s Supply)

The LABs in this jar have always been active and “happy.” No spoilage ever detected. I would use this jar, and it is affordable.

Jar 14 (Pickl-It purchased through the generosity of GNOWFGLINS)

It was nice to be able to test this jar after having it untouched for a few weeks. The LAB activity was great, although the LABs seemed smaller than other jars. I would recommend this jar because it works, although I wouldn’t use it personally. The airlock installed is redundant as the gasket itself acts as an airlock. If you can afford this jar, I suggest grabbing a few Fido’s instead for the same price.

Jar 15 (Harsch purchased by the generous donations largely from Homesteader’s Supply along with with GAPS Diet Journey, Hybrid Rasta Mama, and Dishrag Diaries)

I am completely torn about this crock. I did get a faint whiff and taste of mold when I tried it on Day 28, but I didn’t detect any in the brine visually or under the scope. I am going to try it again with larger cabbage pieces that won’t float to the top and see how that works out. Even without the mold, there are other far less expensive jars that do a great job.

Jar 16 (Bucket)

I am not surprised this method failed. This was covered with cheesecloth, but just look at the mess. By Day 10 I had to toss it. I won’t be re-testing this set-up, and I don’t recommend it.

Jar 17 (Fido)

It was fun watching the brine foam out of the side during the gaseous stage. It was a blast opening it on Day 28 (did you see my video on YouTube?). LABs were mature, active, and densely populated. This jar didn’t let me down. This jar was sealed the entire four weeks and did a great job holding in plenty of CO2 for pressure – just like it was designed. Exploding jar myth? Pay no mind.

Jar 18 (Salsa Jar)

This little jar surprised me. It has a great seal – in fact it’s so tight the pressure in the jar had nowhere to go but out my test port. This explains why there was no brine covering the cabbage by Day 10, and I had kick this little guy out. By itself, it could hurt you due to pressure build-up, so I only recommend this jar if you install an airlock. You can get one for $.99 and a grommet for a dime, so for just over a dollar you could have a great fermenting jar.

To re-cap without photos… out of eighteen jars, four I do not recommend:

  • Jar #1, Cheesecloth
  • Jar #4, Cabbage leaf held down by small jar
  • Jar #6, White Lid
  • Jar #16, The Bucket

Six  I would use…”if”:

  • Jar #3, Baggy with Water – only if you can get all the cabbage pieces down with none trapped between baggy and glass. A tall order, unless you chop the cabbage bigger
  • Jar #5, Cabbage Leaf with Shot Glass and lid – only if you can keep the cabbage leaf under the brine
  • Jar #9, Metal Lid – seals wonderfully, but only works with airlock (Jar #10)
  • Jar #11, Cork with Airlock – I need to repeat this with a less-full jar to compensate for the cork dropping below the top of the glass
  • Jar #15 – Harsch – I need to repeat this. Whiffs of mold, taste of mold, but none detected in the brine
  • Jar #18 – Salsa Jar – such a great seal – only use with an airlock, though!

Eight I would recommend and/or use:

So there you have it!

Did any of the jars surprise you? Which ones?

Are you going to keep with the same method you’re currently using, or will you be changing jars?

I will report how the jars do in cold storage in a couple of weeks.

Thanks again for all the support!

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proud contributor
Lea Harris founded Nourishing Treasures in 2006. A mom passionate about her family's health and well-being, Lea believes education is power. Encouraging others to take baby steps in the right direction of health for their families, Lea's goal is to raise awareness of what goes into our mouths and on our bodies, providing natural alternative information that promotes health and prevents disease by using traditional foods and nature's medicine.

Lea is a Certified Health Coach graduate from Beyond Organic University, and a Certified Aromatherapist graduate from Aromahead Institute.

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You can also find me on Learning About Essential Oils forum, and Fido Fermentation Facebook group.

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Sauerkraut Survivor – Final Report — 143 Comments

  1. This has been absolutely FASCINATING!! Thank you for doing such a detailed research project and sharing it with all of us! Can’t wait to pop down to the local brew shop and grab some goodies to adapt my collection of olive jars into fermenting vessels!

  2. Thank you for such an in depth experiment! I am going to switch my system to the J10. The way I fermented kraut isn’t in the experiment.

  3. Really interesting results! I’ve never tried to ferment anything for longer than about 10 days, so I can’t say how my original method would have held up. But I just started a ferment today in my new Pickl-It and plan to leave it for 3-4 weeks, so I’ll see how that goes. The Fidos are interesting (and definitely cheaper!) so I might consider buying one of those as well.
    Thanks Lea, for all of your hard work on this, it has been really interesting!

  4. Hi, Lea!

    Thank you again for all your hard work. This has been fun! I’m confused about the bucket, though. Was this your first time fermenting with that kind of setup? I have not used a bucket, but regularly use a large Ohio Stoneware crock, which works in the same way. I have never had anything like that happen. Occasionally I might get a little “mold flower” develop on the brine that I can scoop right off with a spoon. It is very firm and compact, not scummy like what you got. I have gotten the scummy, cheesy-smelling mold in jars. I’m wondering. . . were all the fermenting vessels close together? Maybe they contaminated each other?

    I don’t think I’m giving up my crock. My kraut is too good. Also, it is the same thing my grandmother used. I’m curious though, whether that environment would tend to create more acetic acid than lactic acid, and fewer LABs. Too bad the bucket didn’t last long enough to check the LAB count. I do think the fact that there were so many tiny floaties could have been part of the problem. I slice my cabbage by hand and don’t have many of those, and usually remove the ones that do float up.


    Sarah M.

    • If your method isn’t giving you issues, then it’s probably fine. I actually didn’t have floaties in the bucket, so I doubt that contributed. I chalked it up to the fact it was open to the air and only draped in cheesecloth. That is the bucket method some use, and I wanted to simulate it.

      Cutting the cabbage larger than I did is a great idea. I used my food processor to shred it – I just didn’t have the time to do it all by hand (it took 12 hours as it was! LOL). Now that I’m discussing it, I could have used my “slicing” blade. Next time :)

      Thanks again for taking the time to leave feedback!

  5. Hi. Thanks so much for doing this! I have been baffled about all the info out there lately. I’m concerned about the validity of some statements, being that people may be trying to plug certain products. People have been using crocks AND canning jars for decades with no problems. Their ancestors showed them how. They know it is fermented because of the taste. I know folks thats can taste a spoonful and automatically tell you it’s not done. I have a hard time distinguishing between “done” and “not done” sometimes. You are brave and inspiring!

  6. Thank you for all the work and time you’ve put into this project. You have been so thorough. I will definitely not buy any more pickl-its, and just stick with fidos! I can’t thank you enough for the wealth of information you have given to our blogosphere!

  7. I’m going to nominate you for the Sauerkraut Peace Prize =)
    Thanks so much for everything you put into this project. It has been such a fun and informative adventure!!!

    Be well Leah!!

  8. Thank you, thank you, thank you!!! I adore my sauerkraut (and all my other ferments!) and while I had no intention of changing my method based on the latest hullaballoo, it is nice for the reassurance and to be able to direct any naysayers here! My yummies are safe!

    “Sauerkraut rockstar,” I LOVE IT! Fabulous ferments all around!

  9. Great job Lea. I almost missed some of your updates because, although I joined your e-mail list, I didn’t receive most of them (didn’t go in my spam folder either).

    I’m going to order some Fido jars. I was waiting to hear your outcome.

    Thanks again for taking so much time and giving such attention to detail.

  10. did you use the weights for the harsch? mine has fitted stones that keep all if it under the solution. and i am working to find a low sodium method too. thanks.

    • Yes, I did use weights in the Harsch. I think a good idea would be slicing and not pulverizing LOL I am going to try larger pieces next time.

      If you use a good sea salt, like REAL salt, the salt is beneficial. Plus, you want the salt so as to discourage spoilage organisms.

  11. Thank you so much for all your hard work on this. I am so comforted as I have been using Pickle Pro (Jar 13) for my ferments. I love it as you use your own quart or half gallon mason jar and when you are done fermenting on the counter, you can just put a different lid on it and remove the Pickle Pro top and transfer to the frig. No moving from one container to another. I mainly do fruit chutneys.

  12. Lea, thank you for your work and sharing the results. I hope you don’t mind my questions.

    Is this from one of your other pages basically your recipe for this experiment? “Salt should be added at a ratio of about 2-3%. Much more than this andthe Lactobacilli can’t thrive. A good rule of thumb is one tablespoon of salt per two pounds of cabbage.”

    Can whey replace the salt? If not, would it be helpful to add whey with the salt?

    I’ve been using white plastic lids, with on top a rubber seal and airlock which I bought from a wine-making supply company, and I will probably keep using that method but it seems it would be better to also add a gasket inside the lid to make a better seal. I’d also like to try the metal canning jar lids with a rubber seal and airlock. I’ve never let my jars go for as long as you have and didn’t realize it was so beneficial.

    When you used such lids with airlocks, you didn’t need any weight to push the cabbage under the liquid, correct?

    Did the liquid reach the top of the jar when you first sealed them or is a bit of space and oxygen at the top okay?

    Also, I sometimes use spring water to add some extra liquid to cover the kraut and I wonder if water should be boiled first to kill any unwanted bacteria?

    About fermenting jars like Fido – if carbon dioxide can get out through the seals then why can’t oxygen get in the same way?

    Sometime ago I came across this post on Lacto-Fermentation lowering carbs, thus being beneficial for diabetics, and you might find it interesting:

    Thank you again for testing so many methods and thank you for your kindness and help in answering questions.

    • Donna,

      I welcome questions with open arms :)

      Yes, the 2-3% ratio is what I used. To be exact, I used 15 grams of salt (weighed) for 2 pounds of cabbage. I used REAL salt and this ended up being just shy of a full Tablespoon.

      Many people use whey to replace salt. I have not tried this method for several reasons. One, salt is easier to use, and two, because the bacteria involved aren’t even the same (see: Why I Don’t Use Whey as a Vegetable Fermentation Starter by The Liberated Kitchen).

      I do recommend a gasket between the white lid and top of jar since you’re also using an airlock. I do encourage you to leave them on your counter longer before refrigerating. The nature of the ferment prevents it from spoiling.

      You need a weight for all your ferments, regardless if you use an airlock. Brine is your friend, and you want it covering the cabbage at all times. Otherwise, the top tends to dry out, just from being exposed to the air.

      When I packed the jars, the brine was to the level of the bottom of the cap. You know that bump-out of glass below the threads? The brine reached to there. The cabbage itself, two pounds, hit the three-cup mark. The gaseous stage caused quite a bit of heaving and more brine coming out of the cabbage than I expected, and because I was worried about overflow, I removed about 1/4 cup from each jar. Hindsight being 20/20, I should have not filled the jars so much, or just put out towels and let it overflow :) Not a big deal.

      I do recommend you not adding just water, but a salt water mixture to inhibit spoilage organisms.

      Great question about the Fido’s gasket. I thought the same as you – if it can get out, it can get in. I was wrong, though! It works as a check valve. The seal is such that oxygen can’t penetrate, yet the pressure from the excess CO2 will cause the gasket to move, allowing the CO2 to push between the gasket and the glass. In my earlier Fido photos, I had a photo of the foam on the side where excess CO2 did get out. And if you saw the video when I opened the Fido, you could see it was all CO2!

      I am glad you brought up carbs. That is something I was aware of and completely neglected to mention anywhere. The longer you let your ferment go, the more probiotics and the less carbs. Since the LABs consume glucose for fuel, the longer you leave the ferment, the more glucose is eaten and the less carbs in the final product. This is especially good news for diabetics.

      Thank you for all the great questions!

  13. Pingback: Sauerkraut Survivor from Nourishing Treasures « Corn Free Lifestyle

  14. I’m interested in your response to mold. Maybe you discuss this elsewhere, but in this article it seems that you take for granted that the presence of mold equates to a lost batch. But many of us just scrape it off and eat what’s underneath. I’ve read of accounts of old-time kraut-making in barrels where the mold acts as a lid — you don’t want to eat it, but the stuff underneath is fine. So, how does that sort of understanding of mold play into your decision making about jars and processes?

    • It is true mold = lost batch. I know it’s popular to take the approach that mold or yeast in your sauerkraut is acceptable, but it’s actually harmful. Just because it’s common, doesn’t mean it’s good! The only mold that is not harmful to our bodies is in blue cheese and similar molds that you are trying to make as part of a food.

      In my experience, mold on top, even when removed, still shows up in brine samples in sauerkraut on the bottom of the jar. Even if you can’t see it with your eyes. The roots of mold are far-reaching and give you no health benefits.

      So, if a jar tested for mold, it is not acceptable. We do not want to injest mold spores.

  15. Where would one find the airlocks and grommets? I would like to see a close up of these so that I could know what you are talking about. I have been making sauerkraut for several months. I make it in quart jars with 2 part canning lids – they seem to do fine for me. However, I have only been fermenting for one week and then refrigerating. Am I missing out on something by doing it this way?

    • Here are the grommets: eBay.

      Here are the airlocks: airlocks.

      The 2-part canning lids work very well as a tight seal, but they do need a way of letting the excess CO2 escape.

      Yes, you are missing out on tons of probiotics by refrigerating so soon. Leave it 4 weeks and your guts will thank you! :)

  16. I have been fascinated by your experiment. After watching your posts for a week I purchased Fido jars and began my own experiments. I loved comparing notes. I made Beet Kvass. I compared the Fido to Mason jar with white lid. The Fido made EXCELLENT Kvass. The best I have ever had..even a little carbonation like bubblies….Not so with just the mason jar..It was almost slimy in texture, not bubbly. It was fine to drink but not the same product.

    Did it matter if the product was submerged in the Fido jar?

    • Thank you for stopping by, Mo! It’s wonderful you did your own experiment – I encourage everyone to test out the jars they have and see what results they get in their own homes.

      I think it’s great if you can keep the product submerged. Clearly there is no oxygen in the Fido, so it likely won’t mold, but it’s always best to keep things under the brine. In fact, maybe I should do a test for that: Fido with stuff under the brine vs. Fido with stuff not under the brine and see if, in a Fido, it matters. Hmmm….

  17. I started a batch so I’ll let you know in about a month : )

    I have been using these jars to make water kefir soda (the second ferment) and I think they are working great. They pop and all sorts of bubbles come out like in your video. So I hope that means its good!

  18. I am so totally new to this. My one batch of sauerkraut so far went moldy – not enough brine.

    How do you get enough brine and/or weigh the cabbage to be under the brine?

    Thanks and thanks for doing this experiment. Great info!

  19. So, just to clarify with the Fidos — they are made with the intention of letting gasses escape? I always thought they were a tight seal, but this would make sense because when canning, the lids need to allow gasses to escape, too. I am afraid because I used some Grolsch top bottles for my water kefir’s second fermentation and did have them explode and quite violently. I shudder every time I think of how close my kids and I were to serious injury. We had just left the kitchen when they exploded. I have been too afraid to resume kefir-making. Since I like my kefir fizzy, would the Fidos be safe for secondary fermentation with fruit juice?
    Thank you for this great info!

    • Yes, they are made with the intention of letting gas escape. They are a tight seal as far as they don’t let oxygen in, but at the same time, due to the vulcanized rubber, they do allow excess CO2 to escape when needed.

      Grolsch top bottles aren’t quite the same. I have used them, and they can catch you by surprise. I use the Fido jars for my first and second water kefir ferments and they work very well and are absolutely safe!

  20. Hm, I’m making sauerkraut for the first time and I don’t see the *exact* method that I’m using. I’m using a large pickle jar, and have a smaller jar with water in it as a weight. The smaller jar is close enough to the size of the mouth of the larger jar to only allow about a quarter inch crack all the way around, and the brine is almost to the top. I’m wondering if that leaves too much oxygen exposure, now. I’m only on day four, but no issues yet.

      • Ok, I’m finally getting back to you on how it went.

        I left my sauerkraut out for 20 days on the counter, before putting it in the fridge. I never had any yeast or mold show up, at all. The kraut smelled wonderful throughout the process, and filled the house with the smell. I was very happy, although I’m not sure how much my family appreciated it. :-p

        The sauerkraut has been in the fridge for about a month, and is still doing fine. It’s getting more tangy, however, more quickly than I expected it to.

        I’ve eaten a fair amount already, it’s quite addicting. I’d heard that sauerkraut was good for digestion, but I thought that was just because it promoted good bacteria in the gut over time. But I noticed recently, that when I inadvertently ate some food that I’m intolerant to and had stomach aches, that eating the sauerkraut would immediately calm down my stomach. So wonderful.

        I don’t know if my success was a fluke, or if my process was ok. I guess only time will tell. I’m thinking of making pickles this week.

    • I’m glad you now feel comfortable with fermenting! LABs are “lactic acid bacteria.” These guys consume the glucose in the cabbage and create lactic acid, which are your probiotics.

  21. I’m reading _the Art of Fermentation_ and one of the jars he recommended is similar to the Fido. I want to make some sauerkraut tonight, but I was afraid to try it. But thanks to your in-depth analysis I have no fear.

    I bought my jars here – for a good price. I was using them to make shrub but now have a second use for them.

    Thank you so much for your hard work on this.

  22. In my view the Pickl-it people have done a great job in creating a “problem” and providing an overpriced solution for it. They have done some great marketing and they must have earned a lot of money right now by making people stressed, afraid and insecure enough to either quit fermenting and living healthy or to actually buy an unnecessary and very expensive Pickl-it jar.

    I have always used the ‘Fido’ jars since they aren’t expensive, work great and look nice. So the outcome of your experiment hasn’t surprised me, but I’m very glad that you’ve cleared up this whole issue so that people don’t have to worry anymore or waste any more money

  23. Leah, I posted on another thread of yours about my experiment with a crock pot, a plate and a layer of olive oil. Well, today I opened the package. There was funky layer of mold on the hardened oil which was gross. But below the hardened layer of oil was good looking red cabbage sauerkraut. No floaties except some bits of oil. But after digging the kraut out, it was apparent that something didn’t go quite right. The kraut at the bottom was weird looking. And the smell was off. Not sure if it was packed too tight or if it needed a few more days or if it just went bad. Since this was my first batch ever of kraut, I’m not sure if the taste was normal or off. It seemed off to me. Anyway, I have four jars of Pickle-Pro kraut going that will be done in a couple of weeks so then I will at least have a frame of reference. So at this point, I don’t know if this method was successful. If the Pickle-Pro works, I think I’ll just stick with that and put my crock back in my crock pot.

    • Yes, I remember. I am sorry it didn’t work out for you with the crock pot :( You can definitely tell by the smell, so if you thought it was off, it probably was.

      I am sure you’ll have better success with the Pickle-Pro :) I found it to perform super well for me.

  24. Thank you SO, SO, SO, SO, much for this post, totally cleared some things up for me without hours of research. I am going to do the route of the fido, best price and I can find them locally. Thanks again, this was an awesome series of posts.


  25. I do have a question though, can I use a jar just like the Fido but not by that brand or is there something special about the Fido?


  26. Hi there! Loved your post. I was wondering if I could use Tattler lids with regular rings instead of the Fido jars. The Tattlers have a reusuable BPA-free white plastic lid with a rubber ring, for use with a standard metal canning ring. What do you think? If so, should I tighten the bands, or just loosely turn? Thanks!

  27. Pingback: The 3 Biggest Fermenting Mistakes You’re Already Making | Food Renegade

  28. Great experiment! I’m also a big fan of strictly anaerobic fermentations, but as far as I can see, you didn’t adequately test my favorite option, which is also cheaper than any of them! My preference is for a mason jar using a white plastic lid with a canning jar seal underneath and no airlock. Second would be a canning jar seal with a metal band instead of a plastic lid, but the metal bands rust very easily. The reason I don’t favor the airlock has more to do with storage than with anything else, but cost is also an important factor. I find that if all air is purged from the jar by the CO2 created during fermentation the food can be stored in the jar for a long period of time until it is opened. I put up green olives, and peppers in large quantities and keep them sometimes well over a year on the shelf without spoilage. But that is only possible if the blanket of CO2 is intact, or if the jar is absolutely full of brine. If there is an airlock sticking out of the top of the jar, that makes it inconvenient to store and the water in the airlock can evaporate leaving the food vulnerable. If the jar is opened to remove the airlock so that it can be replaced with a lid for storage, then air is let in, so I find it best to use a canning jar lid in the first place. Using regular old mason jar lids and seals is very similar to the European style jars which you are referring to as Fido jars. I like those too, but they are not cheap and the salty acidic brine corrodes the metal wire eventually.

    There are some problems with the canning jar seals that are worth pointing out and I think there is a more ideal solution waiting to be invented. One problem is that the brine often spills over during fermentation which is not often the case with airlocks (depending on how full the jar is). The other problem is that the metal seal will eventually rust during storage. I use both new and used seals, as long as the used ones are not scratched on the underside. Neither of these problems is a deal killer however when compared to the existing options. Some aspects I like about the lids is that they are inexpensive, and that one can use any size of jar from a 1/2 cup to 1/2 gallon and then put it away for later use once the primary fermentation is done. So, I can divide my gallons of Kraut into pints or quarts each fermented in it’s own jar and tucked away safely until I want to open one. Actually, I prefer to store Kraut in the fridge after primary fermentation, but I have stored it at room temperature for up to a year and still had edible Kraut. After opening I always store ferments in the fridge.

    It appears that you didn’t adequately test either the Plastic lid with a seal underneath, or the metal ring with seal. I may be misinterpreting, but it appears that you’ve made the assumption that if you had not released the pressure with your test port, that the pressure would have built up and blown the lid off? If so, that assumption is erroneous. I have used these for over 10 years every year and pressure is just not an issue beyond that it can cause some leakage of brine out the edges of the jar. If the lid is screwed on extremely tight, it can cause the seal to bulge out and could presumably break the jar, but I have only done this one time and I screwed the lid on very, very tight. The lid bulged, but the jar did not explode. The other problem you point out is that a person may not screw the lid down tightly enough. In my experience, that is not a problem. Screwing the lid on moderately tight is ideal allowing gasses to escape as long as there is pressure in the jar, but preventing the ingress of air with the subsequent reduction of that pressure when fermentation subsides. The jars are made to function this way in a canning bath where expansion of the food and gasses in the jar create internal pressure that must be purged from the jar during processing, but not allow air or liquid back in as the jar begins to cool. The only time I’ve had trouble with lids not being tight enough was when experimenting with screwing them on just enough to let gasses escape faster to reduce overflow of the brine. At this point I’m inclined to just put the lid on moderately tight and then snug it down prior to storage. I have never had a jar break from pressure.

    I also do not use anything to push the food under the liquid anymore. I’ve found that it just doesn’t matter that much. With a blanket of inert CO2 in the jar the food will, at worst, sometimes slightly discolor in the small area exposed above the brine. I think that pushing the food below the liquid is a practice left over from fermenting in open containers where it is extremely important. Open container ferments are semi-anaerobic though allowing for the formation of scums and moulds on the surface of the brine and you don’t want those scums growing on your vegetables. In truly anaerobic ferments pressing the food below the brine doesn’t seem to be necessary although I always start them covered with brine. I would use something if it was convenient or part of a very inexpensive device, but when putting up large amounts of food, I can’t be bothered anymore. The one advantage I can see of a pressing plate of some kind is that it would allow the use of less brine. If the brine is further down from the top of the jar, then it is less inclined to overflow during fermentation, so I think using such a thing could be useful. My problem is typically that I am doing enough jars that it becomes inconvenient to find enough items to press the food below the surface of the brine in dozens of jars. I think the ideal device would have such a contrivance, but again, under the circumstances, I find it most practical not to bother.

    I’m not a big fan of harsch crocks. They are ridiculously expensive, high maintenance and when you get all the kraut done you still have to put it up in airtight containers.

    I am not at all opposed to fermentation in large open containers and that is how people have done it for centuries, so it clearly works. I would just propose that if people in the past had possessed the technology to produce sealed anaerobic ferments they would have used that technology and that very anaerobic ferments are lower maintenance and more reliable. I am also not against airlocks. I use airlocks for large ferments in carboys sometimes as well as for making cider and wine. I just do not think the expense or hassle are warranted in lactofermentation of vegetables in small containers. I have used a lot of different set ups over the years, but over time have simplified to the most basic functional method. Fermenting in the jars you will store in is very efficient. In summary, don’t waste your money on airlocks when you don’t need to! Just try the white lid with the canning seal. I’ve put up hundreds of jars of stuff this way and it’s pretty fool proof. If you want to minimize spillover, which is the only major issue with this method, use a press plate of some kind to keep the food below the liquid an leave 3/4 inch of space between the top of the jar and the top of the brine. Don’t open the container until the food is to be eaten, then store in the fridge until it is consumed.

    Below is a link to my pepperoncini article, which needs a little updating, but probably has more information than most people want to know about practical details of lactofermentation.

    • Steve, thank you for such a calm and intelligent reply. In an environment of doubt, fear, and expensive jars it was the best thing to read about your successes using cheap simple products. Thank you especially for the reminder that jars used with the 2 piece lids are made for off gassing in the boiling water baths. Duh!
      I also find it reassuring that we really don’t have to submerge the veggies under the brine. This was after discovering a couple of days ago that the small regular mouth plastic lids fit inside of wide mouth lids, and they can be weighted down with decorator’s glass stones or marbles. All that can be sterilized well. I plan on trying that out soon. I had tried to put glass marbles in a small baggie in the top, but the bags got bloated with air as they’re difficult to sterilize – yuckie. Thanks again.

  29. Thank you for your hard work in researching this. I have been searching all over for more traditional ways of fermenting food. (The Whey way does not seem right to me) I have also been looking for what jars to use. I had placed an order with the Pickl It website and for some reason, after two weeks, my order had not been shipped. When ordering, I was told that I had to use the pickl it jars to store my food in , so that meant I had to buy about 500.00 in jars. ( I do a large garden ) After your research in jars, I feel safe in using fido jars. Or even mason jars. (even though I dont like the idea of the BPA in the lids) I was able to find some Fido jars at and got a total of 1 – .5 liter, 4- 1 liter, 6- 2 liter, 3 – 3 liter, 1- 5 liter, and 12 extra gaskets plus 4.95 shipping for less money than the 5 jars from Pickle it. You have saved me so much money and making it possible for me to ferment my own food and heal my belly!!!!

    • No, whey doesn’t make sense when you’re talking veggies. Crate and Barrel has wonderful prices for Fido’s as does Sur la Table ( I purchased quite a few myself. If you have a Christmas Tree Shoppe near you, they have even better prices!

      Thank you so much for taking the time to leave your comment. :)

  30. I just read your experiment with great interest, and was hoping to see the Weck jars I’ve been using. I’d love it if you’d take a look at this link and tell me what you think:
    It looks like they’d work similarly to the Fido jars. because of the gasket & clamps. Could you give me your thoughts on these?
    Thanks so much…

    • I have no experience with Weck jars, but I am going to stick my neck out and say Yes, I would recommend them. do you know the country of origin? They appear to work in a similar fashion as Fido’s.

  31. Lea, how do you drill a hole into a metal canning jar lid and have the edges smooth and a perfect circle? Our drill made the hole a bit jagged. Not going to fit the airlock end.

    The white lid with the baggie – was the baggie rubberbanded over the top of the lid and jar? Did you release the carbon dioxide that collected in it?

    Where do you find rubber gaskets that would fit on top a wide-mouth canning jar underneath the white plastic lid? I already have plastic lids with airlocks and grommets on them so I might as well use them.

    Thank you for your help.

    • My husband placed the metal lid on a piece of wood to help keep it flat. It can be filed afterwards so the sharp edges don’t break your grommets.

      No, the baggy was simply slid over the top of the mason jar. No, I did not release any CO2 from any of the jars.

      I was unable to locate any gaskets that would fit under a white lid. The best I could find was rubber sheets that could be cut into circles – but they weren’t food safe.

      Thank you for your comments and questions! I hope I helped you :)

  32. They’re German made. I’ve used them for my standard 14-day ferment, opening up to push down contents as needed. Now that I’ve read your study, though, I’m going to try locking them for the whole 28 days and see how it works without pushing down. Nice to think I can get even better results fermenting using your suggested method.

    • 28 days would be the minimum – I am sure they can go much longer. I have a jar ready to open on 9-8 that will be there 8 weeks and I am going to compare LABs to the one I opened at 4 weeks. I have another I will be opening at 12 weeks.

      The longer the better! :)

  33. I am looking at fermented salsa recipes. Most of these recipes also do 3 to 5 day fermentation. Off hand without experimentation, would you think that longer fermentation for salsa would also brew the higher quality biotics? Is the longer fermentation suggested for most ferment recipes?

  34. Do you have web pages or an ebook that have step by step instructions on it for “learning to ferment” If so, got a link? I managed to get my Fido jars in stock, now I have a 2 liter filled with Chiogga stripped beats and have no clue what to do next!!! I have 3 books and all tell me to do something different and none tell me to ferment longer than 3 days ( I like the way you do it , that makes more sense.) Do I make the brine, ( 1 tbs of salt to 1 cup of water) and poor it in?

  35. Wow – just fantasic Lea, thanks for putting in all this hard work!
    I live in Japan where it’s not so easy to source supplies sometimes, but I’ve been using a brand of jar called cellarmate ( which seems very similar to a Fido and of reasonable quality. Have you heard of them?

    I’ve just noticed that I can also order Le Parfait from a Japan based retailer too, which are a little more expensive but perhaps worth it for peace of mind!

    Happy Sauerkrauting!

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  37. thanks for all your hard work. I’ve avoided trying fermentation because of all the “don’t use the mason jar” stuff out there this summer and the Pickl-it seems so pricy. The ones that you put on your jar seem like a perfect option. However, do you have to seal the jars or anything when you add the normal lids? (is that in the instructions? )

    Also have you seen or heard of this kit? It was under the “you might also like” on the fido jar link.

    I’m brand new to this. I want to do some peppers actually- ive in NM and it’s chile season. I just want to do it effectivly and not too costly. Out of the 2 or three kits that you used a normal jar with, or the fido, which tasted best to you and seemed to have the highest LAB? (either I missed that or something) THanks!

    • It’s tough when you’re told the only option is an expensive one. I am glad to have found several affordable solutions that work.

      No, there is no need to specially seal the jars.

      I am sure the Perfect Pickler would do well. I see it has the little cup to keep the brine down, and the gasket around the top rim of the glass. I have not tested it, but looking at it, I would say it would do a good job of sealing out the oxygen and allowing the CO2 to escape.

      My two favorite mason jar lids are Cooking God’s Way’s Airlock kit and the Pickle Pro.

      Let me know what you end up using :D

  38. I just put up 2 fido type jars of sauerkraut last week and I noticed that the kraut is now above the brine. It seems to be drying out. There was a ton of brine above the cabbage to start with though. Do you think it will be O.K.? I don’t want to open it and expose it to air.

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  40. Couldn’t you use an airlock device on the bucket? Drill a hole and add one. Or use a beer fermenting bucket…. We use one at work to make kraut.

    Also, to take off the olive oil from the top pop it in the fridge at the end of your ferment. The oil should solidify..

    • I used to use an airlock on a 5 gallon bucket having been a home brewer for years. It works well for fermenting large amounts, but not too well for storage as I didn’t have enough room in a fridge to keep the whole pail in. After I took out a couple or 3 week supply, I sprayed inert gas (argon) on top of the brine to prevent spoilage or bloom, and recover with the lid and a regular cork in the hole. This gas is expensive at a wine store or relatively cheap at a wood working store:,190,44133,30268 I also found that when I would take 3 weeks worth out of a pail and store them in smaller plastic containers that sometimes they would get air in the containers and spoil slowly in the fridge. Also occasionally, I would loose a lot of the pail contents if the garage got too cold and froze or it got too warm. I have quit using a pail and now ferment in two litre glass jars with glass rocks to weigh down the veggies. They are sealed with wide mouth two part canning jar lids. During fermentation brine and gasses escape and dribble down the jars, but when they’re done and I open the jars, just like in Lee’s video, gasses and veggies bubble up like it’s boiling. I also noticed after opening that the veggies were “dry” the brine having bubbled to the top. I put some water in the jar to rehydrate them as I have found that dry ferments in the fridge spoil pretty quickly.

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  42. This is incredible! I love moments like this — where a community who cares about something gets together to better it. So you’re not a scientist… so often studies are just funded by different companies, anyway. Much thanks to you and your devoted companions.

    I’ve recently begun to learn about lacto-fermented foods, but have never attempted them. I’ve never personally tasted these foods, or known anyone who makes them. With so much talk about possibilities for mushiness, mold, LAB growth and taste, it is overwhelming.

    I’m thrilled to find this page as I’m about to dive in to this for the first time.

      • Thank you! I will definitely be doing that in the near future.

        I have one quick question if you can spare a moment. You mention the optimum fermenting time for sauerkraut being 4 weeks. Do you know if the time would be different for say, pickles? Or could you point me to another resource?

        I’m told even in NT they recommend shorter times for ‘kraut so I wasn’t sure if there were any dependable resources on timeframes like that.

        Again, thank you! Have a great day.

        • Pickles go through the same bacterial cycle as sauerkraut. I’ve done my pickles 4 weeks and they are great! Most other vegetables can go just 2 weeks (although I have not yet experimented with all of them). I have let beets go 3 weeks and they are delicious. But I have not tested them at varying times like I did the sauerkraut.

          Everything is shorter in NT. They want it right in the fridge within a week or so. I don’t agree with that method – and neither do any microbiology texts! :)

  43. Thank you so much for the great info. I am new to fermenting but excited to learn it. I did make a batch of kraut in a class just using a mason jar with the lid on loosely. I let it sit for 2 wks before eating and love it. As I sought more info, it got more confusing about the types of jars to use and the accessories that go with them. So, I trying a few different types- pickle jar with air lock, fido jar. Ordered the fido jars from Crate and Barrel great prices. Hubby drilled holes in lids of pickle jars for air locks.
    The problem is that the brine went up the airlock, turning it pink (kraut with beet shreds)then it went clear again. The jar had brine to the bottom of the rings on the jar, the vegs were about an inch below but the contents seem to have expanded, even though I used a cabbage leaf over the top.
    1. should I pack the jar less so the bring doesn’t end up in the airlock?
    2. is it ok to have the bring go up into the airlock?
    3. can I use the food dehydrator screens you mentioned to keep the vegs down or do I need to put some type of weight on top of them?
    4. how much space should I leave when packing the vegs into jars, does it matter if using a fido vs pickle jar?
    5. when putting the air lock into the stopper, should it go all the way down in the stopper or just half way? I do have then almost to the bottom of the stopper.
    Sorry for all the questions and thank you for sharing your knowledge.

    • First, welcome to the fascinating world of fermenting :)

      1 & 2) You do want to make sure your jar is packed to the shoulder, but no more. This allows room for heaving, without it reaching your airlock. Although it’s not “bad” to have this open, it does expose your brine to oxygen, and that is something we’re trying to avoid when fermenting sauerkraut.

      3) I found the dehydrator screens wedged well even during heaving, and the weight was not needed. I also found that you don’t even need to weigh them down if you use a Fido jar. Check that out here:

      4) I would not pack above the shoulder. No matter the jar you use, it will heave.

      5) As for the airlock, you want to push it down so the tip (where the holes are) are sticking out. But remember, the more you push it down, the greater the chances the brine will come up into it.

      Let me know if you have any more questions! :)

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  45. Thank you, Lea, for the prompt and helpful responses. I pulled some of the kraut out, to get it below the shoulder, placed a cabbage leaf on top and added some brine as it was not covering the cabbage leaf. Within hrs it heaved its way back up but no brine in airlock. My husband is now watching this whole process and thinks I have lost my mind, again! I can’t wait to get my fido jars, they seem to be the way to go, at least for beginners. Thanks again.

  46. Thank you for doing this. I started checking a couple ferments I’ve got going right now and caught a couple of ‘em with a little bit of mold on the surface. First, does it make any difference with veggies in brine, such as beets? And second, have you ever caught a batch early enough with just a little mold on top and checked the rest of the batch to see if that was enough to ruin the whole thing? I’m contemplating getting a microscope now just to make absolutely sure. I brought a bunch of these to my dad’s house for thanksgiving, the last thing I need is for people to actually get sick from my kooky “bacteria” laden food…

    • Mold is mold and should never be acceptable. I have tested to see if the mold on top affects brine on the bottom of the ferment where there is no visible mold and yes, I can see mold spores even that far away. Jar #3 was done in 1/2 gallon mason jar, and there were a couple of pieces of cabbage trapped near the top between the baggy and glass. They got slightly fuzzy. I took a sample of the brine that was at the bottom of that jar, and detected mold :(

      It is frustrating to get mold, especially when you invested the time and money into the food. But it’s just not worth the health risk.

      That said, it’s possible you won’t even feel sick if you eat something like that, due to the bacteria in our guts that helps deal with mold and other pathogens in our food. But I don’t recommend making a habit of it! :)

  47. Hi, I want to thank you for all the info you have on this site, it’s so helpful. This may be a stupid question, but I’m not sure if I understand what a FIDO jar is. I have 2 crocks at home, and I am making sauerkraut at home, but I’d like to do a bunch of other vegetables like beets, and I have several mason jars I’ve bought for $5-10 each in the past, and they have the rubber seal and clamp down lid. Are these Fido jars, or is there something special about Fido’s that I am missing?

      • Those look like them…, but they seem more expensive. $15 for 25 ounce/.75 litre for example, whereas I got one of those for around $5-7 in Victoria, Canada. But otherwise, they seem like the same…just a glass jar with a lid that you pull that metal thing on the side to clamp it down, and it seals pretty tight because of the circular rubber thing around the bottom of the lid? That’s great to know that these could work for fermenting, instead of Fido’s or especially Pickle it’s, because I couldn’t afford too many of those…

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