The Science Behind Sauerkraut Fermentation

I’ve been eyeball-deep in microbiology and ferments the past two weeks. I had just purchased some cabbage and was about to start my sauerkraut ferment when I first heard the theory mason jar ferments are less than ideal due to the lack of airtight seal.

Like many of you, I was scared I would be harming my family’s health, yet unable to afford an expensive jar. I was confused that a familiar method was no longer safe.

I was totally out of my comfort zone on this one – I admittedly didn’t have enough experience with microbiology to know if she was right. Some of it made sense, but surely she was wrong on other points. I didn’t like this torn feeling in my gut. I had to know. Is mold really that scary? Is oxygen really a threat? Are mason jars really evil?

This post is born out of endless hours of research gained, sleep lost, and too many hours of my children parked in front of movies. I thought some of you might like to read what I have discovered.

What did traditional cultures use for ferments?

One of the first things I wondered was, “What did traditional cultures use?” Because certainly they didn’t have an airlock like we have. Obviously, they also didn’t use mason jars. So what did they do?

Traditional fermenting crocks were made of pottery or clay. Cabbage would be packed tightly in, a cloth large enough to drape over the crock and cover the top of the cabbage was placed next. Then, rocks were used to weigh down the cloth-covered cabbage. The brine would then be at or over the level of the rocks, providing a brine seal. If any mold did get on the top of the brine, it wouldn’t reach past the rocks and cloth, and the cabbage below was safe.

Often, an additional step was created, similar to the current German and Polish designs of a “moat” around the lid where water would be filled, creating a barrier between the oxygen outside and the ferment inside. The small amount of oxygen left inside would be quickly pushed out with the help of carbon dioxide produced by the lactic acid bacteria. This method ensures air could be pushed out through the water, but none could make it in. Current German and Polish crocks like these were designed from these traditional crocks that were made and used hundreds and even thousands of years ago. They have been updated somewhat to provide for more consistent results.

Koreans had a similar method, but they would bury theirs in the ground, providing a barrier from the air that way.

Other cultures used the stomachs of animals or other various organs that would allow for carbon dioxide to be released without allowing air inside.

So no, they didn’t have a fancy airlock gizmo – but they did have an airlock system. They were clever enough to keep the oxygen out using a simple, yet effective method.

Benefits of Ferments that Traditional Cultures Experienced

The art and science of fermenting foods has been around for thousands of years. Even though traditional cultures may not have known the science behind fermenting, they did not have refrigeration and for them it was a practical way to increase the “shelf life” of their food supply.

What traditional cultures experienced were the benefits of increased vitamins levels in the final product, and the ease of digestion a fermented food, like sauerkraut, gave them.

Although they couldn’t have realized naturally-occuring toxins were reduced and pathogens were destroyed, they saw the detoxifying effects of the acidity of sauerkraut by the fact that it did not spoil. What they had was a food full of lactic acid bacteria which has now been discovered to not only be probiotic, but is also effective in protecting one’s self from cancer.

What’s going on in a ferment, anyways?

Fermentation in general has been defined as “a biochemical change which is brought about by the anaerobic or partially anaerobic oxidation of carbs by either micro-organisms or enzymes.” This is distinct from putrefaction which is proteins being broken down.

In sauerkraut, the fermentation process has a very specific purpose: to quickly proliferate through the food by lactic acid-producing bacteria (LABs), primarily Lactobacilli. These Lactobacilli cause the pH to be reduced, making the environment acidic and unsuitable for the growth of unwanted bacteria. Since the goal of making sauerkraut is to provide the best environment for Lactobacilli to grow, it pays to get to know LABs and what makes them thrive.

What Are Lactic Acid-Producing Bacteria?

Lactic acid bacteria (LABs) produce lactic acid as the result of digesting carbs. LABs are vital for fermenting cabbage into sauerkraut (as well as making sourdough and dairy kefir).

Although LABs in general are anaerobes, which make it very hard for them to live in the presence of oxygen, there are different sub-groups of LABs. One of these are the LAB Producers, and these include the microaerophiles Lactobacilli and Leuconostoc, which are vital for sauerkraut fermentation. By definition microaerophiles require small amounts of oxygen to function.

Now this isn’t a free pass to not cover your sauerkraut. The oxygen present in your jar and on your cabbage when you’re packing the sauerkraut in your jar is sufficient.

The three stages of sauerkraut fermentation

In order for sauerkraut to be a success, it must go through three specific stages of fermentation.

Stage One

Leuconostoc mesenteroides initiates sauerkraut fermentation. Since Leuconostoc mesenteroides produce carbon dioxide, it effectively replaces the oxygen in the jar, making the environment anaerobic (oxygen-free). When lactic acids reach between .25 and .3%, Leuconostoc mesenteroides bacteria slow down and die off, although enzymes continue to function.

This stage lasts between one and three days, depending on temperature.

Stage Two

Lactobacillus plantarum and Lactobacillus cucumeris continue the ferment until lactic acid level of 1.5-2% is attained.

High salt and low temp inhibit these bacteria, so I hope you didn’t over-salt your cabbage – and be sure not to refrigerate yet.

This stage continues for 10-30 days, depending on temperature.

Stage Three

Lactobacillus brevis (some sources also include Lactobacillus pentoaceticus) finish off the ferment. When lactic acid reaches 2-2.5%, they reach their max growth and the ferment is over.

This final stage lasts under a week.

You will know your sauerkraut is ready for long-term storage (or to eat!), when no more bubbles appear on the sides or top of your jar.

There is a nice image of the stages here.

What can affect the way my sauerkraut turns out?

Although the process is simple, and will complete well on it’s own with the right amount of salt added, there are some factors that do influence how sauerkraut will turn out. These are: moisture, oxygen concentration, temperature, nutrients, and pH. Let’s address these one at a time:


Bacteria that love to spoil sauerkraut will have the upper hand if you have an insufficient level of brine. Too low a water/brine level and you’re giving the undesirable aerobic (oxygen-loving) bacteria and yeasts the food they need to grow on the surface. This can cause off-flavors and discoloration at minimum, or even an allergic reaction to those with sensitivities to mold and yeast.

Although white yeast “scum” on the surface can be scraped off without harm to you, mold is another story and will be addressed further in another section. Briefly, one way to eliminate the mold problem (because you certainly can’t drain the moisture out of your ‘kraut) is to make sure oxygen exposure is kept to an absolute minimum since molds need oxygen to survive. Which brings me to…

Oxygen Concentration

Lactobacillus plantarum, the primary bacteria responsible for Stage Two, works best without oxygen. Anaerobically (without oxygen), Lactobacillus plantarum does their job the way we want them to – they cause fermentation of cabbage via lactic acid. Aerobically (with oxygen), it will produce acetic acid (vinegar). Since we’re making sauerkraut, oxygen must be avoided.

Sauerkraut that is allowed oxygen will not contain any vitamin C in the final product after just six days. It will also increase chances of mold forming. If you are regularly getting mold on the top of your cabbage, this is a visible sign you are allowing too much oxygen in. Oxygen also allows pink yeasts to grow and could result in soft ‘kraut.

Finally, don’t mess with your brine. When brine is stirred, you introduce air which make conditions more favorable for growth of spoilage bacteria.


Micro-organisms are classified into three categories according to their temperature preferences. Since sauerkraut falls into the mesophilic category, the bacteria involved prefer a minimum of 50-77° F; an optimum of 86-104° F, and a maximum of 95-112°F. These are the temps that all bacteria prefer (non-pathogenic as well as pathogenic).

In the first stage of fermentation as described above, the Leuconostoc mesenteroides from stage one likes a temperature range of 65-72° F. It’s a little flexible, and built to resist some change in temp.

The second- and third-stage bacteria Lactobacillus plantarum, Lactobacillus cucumeris, Lactobacillus pentoaceticus, and Lactobacillus brevis prefer a temp of 72° F – 90° F.

It’s important to keep these temps in mind, to be sure you provide the right environment for these bacteria to grow.

Temperature also affects enzymes, which are destroyed once the temperature has risen to 115 degrees.


Nutrients also affect the outcome of sauerkraut, salt being the primary nutrient of concern.

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.

Be sure to add salt as evenly as possible – if you create pockets of cabbage that aren’t salted, you are sending an open invitation for spoilage bacteria to invade and turn your cabbage brown, or for yeasts to turn it pink.

It is essential to use pure sea salt. Salts with added alkali may neutralize the acid, resulting in a failed sauerkraut.


pH is a measure of hydrogen ion concentration. Foods with a pH above 4.6 are low acid and these foods won’t prevent bacterial spoilage.

However, since sauerkraut has a pH of 4.6 or lower, it is termed a high acid food. This acidic environment will not permit the growth of bacterial spores and thus is resistant to spoilage.

Lactobacilli thrive in an acid environment, but so can molds and yeasts. So it’s important to find out what the mold and yeast don’t like that Lactobacilli can tolerate in order to prevent mold and yeast from growing at all. I discuss this next.

Signs you’re doing it right – or wrong

Okay, so now you know the particulars on moisture, oxygen, temperature, salt and pH. It’s easy to tell if your brine is above your cabbage, and you can use a thermometer to check temperature. You’ve measured your salt correctly, and you can use pH strips to test the acidity. That leaves us with oxygen. How do you know if you’re keeping out enough?

Fortunately, there are visible signs to help you figure out if your set-up is working.

Firstly, you will see your cabbage darken. It will turn a brownish color. This also tells you your vitamin C content is tanking – or gone. If you have a pinkish color going on (and it’s not from adding red cabbage) then you have a yeast issue. Finally, you could have mold.

All three of these are preventable. All three, like lactic acid bacteria (LABs), can survive in an acidic environment. But how do you kill off the yeast and mold without harming the vitamin C, and while keeping the lactic acid bacteria happy?

Keep the oxygen out.

Yeast and mold both need an oxygen source to thrive. Vitamin C deteriorates when exposed to oxygen after just six days.

The “Big Deal” About Mold

I know, I keep bringing up the mold issue. It’s such a wonderful big red flag that I can’t help but use it as a visible clue something is going wrong.

And you’re asking yourself if mold is a big deal or not. After all, some cheeses mold and that’s supposed to be a good thing – so what’s the crime if sauerkraut molds? Can’t you just spoon it off and throw it away?

Well let’s check that out.

The first thing you need to know is that moldy cheese is created on purpose. Gorgonzola or blue cheese that has been cultured to create mold is different than moldy swiss cheese or even cheddar. Saying moldy sauerkraut is acceptable because some cheeses are meant to mold is like comparing cheese to sauerkraut :) On a microbial level, it’s a whole other world.

Further, scraping off the mold leaves it’s roots behind, and ingesting this can end up causing problems in the long run. Those already sensitive to mold can react immediately – they can tell you it’s nothing to fool around with. Others may not get sick right away, but in the long run? I really don’t want to take that chance, personally, but you are free to make that decision for your own family.

A Word on Yeasts

Yeast is another major inhibitor which requires an abundance of oxygen for growth. It’s often one of the first signs that you’re allowing too much oxygen near your sauerkraut. In the presence of oxygen yeasts can be oxidized to form vinegar - not something we want in our sauerkraut. Yeasts can also cause off-flavors and discoloration, visible signs you need a better seal on your sauerkraut. Pink sauerkraut (not from red cabbage) is a sign of yeast. This could be due to too much salt, or an uneven distribution of salt, or too much oxygen exposure. If you see a creamy film on top and/or one that smells yeasty, throw it out.

There is one yeast, however, that is helpful. Saccharomyces cerevisiae, a member of the ascomycetous yeast family (as opposed to the candida family) is probiotic and can help with candida overgrowth. Interestingly, Saccharomyces cerevisiae has the ability to shift its own metabolism from fermentive to oxidative. Do you know what causes it to make the switch? Oxygen. When present, oxygen will cause Saccharomyces cerevisiae to oxidize; keep the oxygen out, and this friendly yeast can help your sauerkraut to ferment and provide you with delicious probiotics.

White Film, Slime, Sediment, and Starter Cultures

Although mold is harmful, white film is not. This is just your friendly probiotic yeast at work. This happens more often when cabbage isn’t properly submerged under the brine, or the container isn’t sealed well.

Slime, however isn’t to be tolerated. This is most often the cause of too little salt, or salt that wasn’t evenly mixed into the cabbage.

What about white sediment on the bottom of the jar? A small amount is normal and a good sign. When coupled with slimy sauerkraut, it’s a bad sign.

Starter cultures – are they bad? Although unnecessary, they aren’t to be frowned on. Starter cultures can ensure consistency and speed up the fermentation process. Controlling a ferment in this manner can give consistent results.

The Bottom Line

If you’re aiming to make sauerkraut, you want to be sure you do all you can to encourage the good bacteria to grow (correct salt ratio), and to keep the bad bacteria out (suffocate them!). It’s part art, but mostly science.Since we know what environment the good bacteria prefer, and what the bad ones don’t, it should be easy to get great results with sauerkraut.

What I Learned

What I learned was oxygen IS a very important factor. Although I thought it was over-rated at first, I believe after educating myself that it is one of the most important factors of all.

I also learned how harmful mold can be – and more importantly, how to use it as a sign things are going wrong.

I learned we can’t trust trends. Just because “everyone” has been using a certain jar set-up for the last decade, doesn’t mean it’s ideal. Accessibility and low cost are motivators, but we need to learn the science behind fermenting before we blindly trust a popular method.

At the same time, we can’t dismiss new methods solely because they are modern. I love my dishwasher, and I like not having to do them all by hand. The end result is the same – clean dishes. Similarly, I love my airlock and since it gives the same results as a traditional method, I don’t feel compelled to give it up.

The Final Unanswered Question – What Set-Ups Will Keep Oxygen Out

Now that I have all the science worked out in my mind, there is one final question that I still need to prove to myself: what set-ups will keep oxygen out effectively? Is a $30 airlock set-up or a $120+ crock truly the only methods of effectively keeping oxygen out? Or will a $15 or $3 set-up be as effective?

What is the difference, from a microbial standpoint, between the various set ups?

This is what I aim to find out, when, in a few weeks, I test for myself. I will have a dozen or more various set ups and will put them to the test. Which will be the last sauerkraut standing? Wait and see…

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Sources: mold 1, mold 2, mold 3, , mold 4, Micro-Organisms and Fermentation, Handbook of Fermented Functional Foods, sauerkraut fermentation stages, controlled fermentation of sauerkraut pdf, Fermented Fruits and Vegetables, a Global Perspective, pickle product problems pdf

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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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The Science Behind Sauerkraut Fermentation — 59 Comments

  1. following with interest, glad someone is testing to compare results of the different methods. And as an aside – I have read that the white yeast “scum” that bubbles up during fermentation is called barm, and that in the past it was collected and used as a source of active yeast for leavening breads. If anyone runs across any information on the technique used to do this I would love to know!

  2. Very insightful post and I’m glad you actually did the research to come to a conclusion rather than knee jerk like many have done to KA’s post ;)

    I would love to see a side by side comparison of several fermenting methods. How are you going to “test” it though? I’d love to be able to see an actual lab test on the bacteria counts, is that possible? I wonder where one could get this done.

    • I don’t want to give away all my secrets (yet) but there is a way for me to test the bacteria at home. I will also be checking pH and of course any visible signs of oxygen getting through and ruining the sauerkraut. I’ll have a dozen different set-ups to compare. It will be loads of fun – I can’t wait :)

      • awesome!!! I had thought about this myself. I was like, why not just settle this by testing…do the same ferment in the same house, same conditions etc…but with all the different methods. Do blind taste tests with people who are used to eating said ferment so they can rate the flavors/taste, crisp or mushy etc…then test for the levels of healthy bacteria.

        I’d love though if we could test for other yeasts and mold activity too or at least photo document if there is any visible signs of molds or yeasts in any of the batches.

        I’m excited to see your results!

        • I will be taking photos. Frequently the first week, then weekly for several months.

          Fortunately, yeast and mold are easily visible so they can be duly noted, as will any browning.

  3. Wowsah! Awesome in depth post!

    So – the recipe in Nourishing Traditions isn’t even really making true sauerkraut – due to the amount of time recommended alone! I wonder if anyone actually gets their home ferments tested for mold/bacteria etc……. which by the way, I will be this week, as my brother works in a lab that tests this kind of stuff. It should be very interesting to see. I do wait until the bubbles subside and longer ferment my kraut and have been doing so for some time now. I think this is super important info to get out there! Thanks for all your research and for siting your sources!

    • I think many people prefer a less acidic flavor. Since they are fermenting “to taste” they miss a lot of the benefits of letting it set longer.

      That is super exciting you have access to a lab. I wish I did :) Let me know your results!

    • You’re welcome!

      If you refrigerate it, it will just take much longer. I wouldn’t say it’s “wrong.” Maybe I will do a test (but not this time) for refrigerating early vs. not.

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  5. Thanks for your informative post. I recently had sauerkraut that I did in a Pickl-It develop a slimy texture (the brine). I was told that it was just going through a stage and would be fine (It also did not have an off smell or taste). I put it in the fridge and the slimy texture developed back into brine. Any ideas? Is it bad? I am still fermenting it.

    • From what I’ve read, slime is not a good sign.

      That said, as much as I have read about all this, there are so many more sources out there. I did not explore slime in-depth. There could be safe slimes and unsafe slimes – it would take me more research before I could answer this one. If it turned back until brine, it sounds like it was okay.

      I’ll jot this down so I can be sure to find out more about this.

      Thanks for asking!

  6. Love your post! And hopefully commenters will be respectful :)

    Actually cabbage based ferments – kraut – go through 4 stages of fermentation – all lactoferments go through three stages – kraut is unusual in that it goes through one more

    From the Pickl-it site which details each stage:
    4. Only fresh, unpasteurized sauerkraut will undergo the final stage for full nutritional and flavor development.
    • Lb. brevis and some other heterofermentative species metabolize pentoses – remaining sugars – such as aribinos and xylose which become dominant (living plant material normally does not contain free-pentoses)
    • Pentose are further fermented to lactic acid
    • The resulting flavor of sauerkraut is a combination of: lactate, acetate, ethanol, carbon dioxide and diacetyl.
    • Total acid increases to 2.5%
    • pH decreases to as low as 3.4

    • Pickl-It is the only website that claims four stages. All my sources list three. Various sources from various decades all show three stages.

      If you look carefully, Pickl-It stage 4 is really ferment stage 3 (L. brevis). Their stage one is “cabbage is filled into containers” which isn’t one of the three stages of fermentation. It’s one of the steps of creating your sauerkraut, just like ” buy your cabbage” and “finely shred your cabbage.”

      The three stages of fermentation are:

      Stage One

      Leuconostoc mesenteroids initiates sauerkraut fermentation. Since Leuconostoc mesenteroids produce carbon dioxide, it effectively replaces the oxygen in the jar, making the environment anaerobic (oxygen-free). When lactic acids reach between .25 and .3%, Leuconostoc mesenteroids bacteria slow down and die off, although enzymes continue to function.

      Stage Two

      Lactobacillus plantarum and Lactobacillus cucumeris continue the ferment until lactic acid level of 1.5-2% is attained.

      Stage Three

      Lactobacillus brevis (some sources also include Lactobacillus pentoaceticus) finish off the ferment. When lactic acid reaches 2-2.5%, they reach their max growth and the ferment is over.

      Thanks for your comment!

      • Farnworth clearly describes four steps/stages of cabbage fermentation. You are correct, stage 1 is when the cabbage is loaded into the container, but that is also the first stage of fermentation which he describes as starting immediately.

        • Well then I want to add another step – when you mix the cabbage and salt, that immediately starts drawing water out of the cabbage and maybe that is when it truly begins. Or maybe when you cut through the cabbage – maybe that’s when it should really begin :)

          The basic message is that three stages of bacteria take place in a ferment. Leuconostoc mesenteroides initiate it, then the heterofermentative lactobacilli, and finally homofermentative lactobacilli.

          Thanks for replying to another one of my posts :) Have a great day.

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  8. Awesome post! I’m eagerly anticipating the results of your test. Too bad it’ll take months to know the results. :) This leads me to a few questions. Are you going to test using a layer of coconut oil on top of the brine to make it airtight? I’m assuming all lacto-ferments need to go through the three stages, not just sauerkraut? I assume not disturbing the brine is only important while it’s going through the 3 stages? Otherwise, how do you get some out to eat without disturbing the brine & introducing oxygen? If you only use up part of the ferment at a time, how do you preserve the remainder? Thanks for your time!

    • Stephanie,

      I will begin testing first week of June, so you’ll see results starting in less than two weeks.

      I will be using an oil layer as part of my test. I will use olive oil, though, so the CO2 can more easily escape though. I’m afraid the coconut oil could be too thick – although that could be a good thing :)

      Yes, the stages are the same for all vegetable ferments. Kefir and kombucha are different, and I will address those next.

      Leaving the brine undisturbed is preferable while it ferments, yes. Once the ferment is completed, you can eat it.

      Long-term preservation is an issue I will be addressing closer to the end of my experiment. Because it is certainly important to keep oxygen out even after fermentation is complete.

      Thanks for your questions and comments!

  9. Just to clarify – the pickl-it site has the sources listed and this is why a fourth stage has been specified by the Pickl-it creator:

    Three stages are for factory-food processors that end their fermentation at Stage 3. For home-fermentation, specifically for kraut, there needs to be a stage four for full-flavor development. I’m very specific and clear about that in this following the example of food chemists. I’m not a food chemist, don’t have a lab, so rely on research and advice from numerous microbiologist and food-scientist advisers that I’ve worked with through the years. I’ve provided the source-material for the construct on that page for 4 stage development of kraut.

    • If you look close their stage 1 is just “pack the jar.” That’s not a stage of fermentation :)

      If food processors skip the final stage (whether that is “stage 3″ or “stage 4″) then fine. But there are three stages of true fermentation that we should all let our ferments go through before consuming.

      Thanks for the comment! :)

    • The one I currently have going is an airlock in cork. It’s doing very well for my kefir :)

      I will include Pickle Pro and Pickl-It in my lineup (as well as the cork) for a total of 17 jars.

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  11. I have been making sauerkraut with just whey and salt, this has been placed in the warm oven with the light on and I have kraut in two days and it is so nice I just add more cabbage to it, and continue making it. I read that you can have it for up to five years this way. I drink the “juice” everyday and need two batches going at once or even three :) We are loving it and enjoy the kraut with beef heart and with our bone broths too.

  12. My big question is if you get an airlock system that is effective what happens after the sauerkraut is complete? Can you cap it and store it in the fridge? Do you have to keep the airlock on it as long as you have kraut left? When there’s very little kraut left in the bottom of the jar will the airlock be effective or will it get exposed to too mucn oxygen?

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  14. I made homemade German Kraut with a friend for a couple years in a row. He learned from his grandfather and was even using the same grater, masher and crock that had been his grandfathers. It was all done by memory…no measuring, just a few tastes in the making. And he used a garbage bag filled with water on top of a plate and then another plastic drapped over the whole thing. It would burp and burble and create its own aroma. My friend would check it every couple weeks. If there was a little bit of foaminess on the top he just scooped it and threw it off. The first year I did it with him we just bagged it and put it in the fridge after it had fermented to the right taste (about 5 weeks). The next year we did a canning method with Mason jars and lids AFTER the usual fermenting process. They were still good a year later. And for me…I have IBS…eating Sauerkraut regularly is a very good thing. :) Thanks for posting all this…love science.

  15. Hi Lea,

    Great site, great science projects! Thanks for all your efforts and experiments. You are totally a dedicated “mad-kraut” scientist!

    I stumbled on your site when I was looking for another fermenting vessel option. I was using my homemade mason jar air-locking system, it worked but made such a mess with the brine being pushed out. Well you convinced me Fido is the way to go. Its so brilliant and make so much sense. I believe the air-locking system is redundant on a Fido jar, like you pointed out the rubber gasket work likes an air lock. So far I have used it for pickling (fermenting) kirby cucumbers, green tomatoes, and kohlrabi with great success!! I tried a fruit kimchi from Sandor Katz’s book, but I didn’t care for it, I guess its an acquired taste.

    I have a question regarding your salt ratio when you make your kraut. You use 1 TAB to 2 lbs of cabbage. I was wondering how you came up with that amount. I have been using 1 TAB to 3 lbs of cabbage with great success. Its so confusing about the salt ratio and there are so many recipes out there with different amounts. As you know over salting can be as bad as under salting.

    I have been using this wonderful little booklet by Klaus Kaufmann called “Making Sauerkraut and Pickled Vegetables at Home.” He suggests:

    Salt to Cabbage Ratio:
    1 tsp salt to 1 lb (454 g) cabbage
    4 tbsp salt to 12 lbs (6 kg) cabbage
    1 tbsp salt to 5 quarts cabbage

    Just wanted to know your thoughts on this.

    Again thanks for your hard work and efforts on the science of fermenting!


    • Thank you for stopping by – I love the “mad-kraut scientist” title. WOOT! :)

      I got that from the Harsch booklet that came with my Harsch. When doing Sauerkraut Survivor I wanted consistency. Since they recommended that for the Harsch, I used it for the other jars as well. There are varying amounts of salt recommended. I did weigh it and used 15 grams of salt per 2 pounds of cabbage. I used REAL salt. It was a little over a tablespoon measured.

      I wouldn’t go with the 1 tsp per pound. That just isn’t enough. You want 2-3% brine for cabbage. 2% for the 1 pound, at the 454 grams you typed out would be 9 grams salt. Double that and you have 18 grams salt for two pounds. 3% brine would be 13 grams per pound. Going by that, the Harsch recommendations are a little lower. I haven’t had a problem with it, though.

      • O.K. I can see the logic and also you wanted to be consistent concerning your experiments using various vessels and some might not be air tight.

        However, my curiosity took over, I did a search and found a Harsch booklet posted online (yippee.. how did we ever live without net before..). What I found surprised me, you said you use 15 grams per 2 pounds, but that amount is the maximum Harsch recommends:

        The Harsch booklet’s salt ratio:

        “5-8 kg. (11-17 lbs.) Cabbage for the 10 liter pot
        5-8 g (max 15g ) salt for 1 kg. (2.2 lbs.) Cabbage
        The better the pot is sealed the less salt is required.”

        What could be better sealed than a Fido jar since you proved that hands down!

        The booklet had some interesting recipes and one they used whey. I use whey in all my ferments, however, this latest batch of sauerkraut I didn’t, again I was curious, because of your recommendation. I will have the pleasure of tasting that in four weeks (plus I used the salt ratio recommended by Kaufmann).

        The Kaufmann booklet I mention earlier also suggests using whey or a starter for all veggies but it is not necessary for cabbage or cucumbers. He recommends whey or a starter because without help it will ferment slowly or not at all. I have been using whey in all my ferments and they always turn out great. I did have a couple of batches of pickles tasting a bit off but I think that was caused by the blossom ends, so now I cut the ends off and no problems since then.

        I’m just trying to find the least amount of salt I can use safely and I feel the between the Kaufmann and Karsch booklets they help me to understand the ratios I need. I admire the folks that can just throw it in, taste it and know its salted enough, I’m not one of those so I need a number and scale.

        Also have you seen the Pickl-it website regarding their brine water/salt ratio chart? I think its helpful when you need to make brine for veggies that don’t make their own like sauerkraut.

        Happy fermenting…… Irene

        • There are so many suggestions for salt out there. If you want the least salt, try the 5g’s per 2.2 lbs and see how that works for you. Is there a reason you are trying to avoid salt? If you use a mineralized salt (I like REAL salt. If you use regular table salt (white stuff that has been bleached), then I understand :)

          During some recent research, I found pickles need 5-8% or maybe more of salt. I disagree with the 3.5% brine.

          Play around and see what works for you and your jar and home :)

  16. I guess its a matter of taste and health. I don’t like salty foods. I don’t like to consume a lot of sodium, regardless if its sea, real or table salt, its still sodium. I eat fermented foods all year, so yes I’m concerned about sodium intake.

    I never used table salt, its either sea salt or pink Himalayan.

    You said you found that pickles need 5% – 8%, I disagree. According to Sandor Katz, a 3.5% brine make a half-sour pickle and it is acceptable amount, which I had great success. He also said that 5.4% makes a salty sour pickle, which is fine if that is the taste you’re after. However, 8% is very high and I would be surprised if it fermented at all. Salt and Temperatures work hand in hand. According to Sandor, “A general rule of thumb to consider in salting your ferments: more salt to slow microorganism actions in summer heat, less salt in winter when microbial actions slows.” Wild Fermentation is a great book, worth checking it out…

  17. We’ve never done cabbage before. This is how we did it, we shredded the cabbage, put it into the quart jars, poured boiling water in jars until full, put salt and vinegar in each jar. Then we sealed the jars and are letting them ferment for 6 weeks. It is now been about 2 weeks and the lids on the jars are starting to bulge. Is this OK, and if not what should we do? Your help is greatly appreciated. Thanks, Tami

    • Oh dear. :)

      Well first of all, if the jars are about to bulge, I would carefully place a towel over them as you try to unscrew them slowly to release the pressure.

      Secondly, if you ever want a probiotic food, you never, ever want to pour boiling water over it. This kills the lactic acid bacteria that you need to create the ferment.

      Check out my FREE Sauerkraut 101 video ecourse to see how I made mine. You can sign up here:

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  25. I have made many mason jars of Sauerkraut with only one bad one and the only problem with it was to much salt. It was my first. The tricks, one it is much like making yoghourt. Keep things sterile this is very important. tools, jars, boil water etc. Use wood tool and glass bowls not metal. The first set I made stopped fermenting before it was good enough that could have been to much salt but from then on I put in vinegar to help it out and have not had a bad one since.

    Because it is cold here,Live in the redwoods. I put it in the oven to keep it warm. In the winter I put a towel around them. Yes ideal it need to be kept at about 100 deg. I turn on the oven set it to the lowest temp which is 170 when it preheats I turn it off and put in the jars. This I do before going to bed an before going to work. I open them up and stir them and push it down and put in more brine if it does not cover it. (I save some in the refrigerator when I made it. Always keep the cabbage covered. Keep the jars tight but no so tight as to keep the gas that is formed in.

    Yes salt is necessary. It kills the bad bacteria but not the good. To much salt prevents complete fermentation and way to much kills all the bacteria, not to mention makes it tastes salty.

    You know it is finished fermenting when it stops bubbling. That usually means the bacteria used up its food and died. After that it can go bad if you leave it out. Once in the refrigeration it will stop fermenting. Yoghourt that sits in the refrigerator long gets tart. That is acid forming. Same with Sauerkraut, not bad but some do not like it. Most Sauerkraut is pasteurized so yo do not get the beneficial bacteria. So making it is the only way to go and it is much more loaded with beneficial bacteria than youngster.

  26. First you need to sterilize everything. Mix the boiling water and salt let cool to about 100deg then put in the vinegar. Put the cabbage in a large glass bowl and pour on the brine vinegar mixture. Push it down mix it up and make sure it is all covered then cover the bowl with cheese cloth and let it sit for a few hours. It should be bubbling and that tells you fermentation has started. Then put the cabbage in the jars and fill with the same brine. The brine needs to be about 100 deg not much more otherwise it will kill the bacteria. The expanding jars mean it was generating gas and not necessary good. You do not tighten them so tight gas cannot get out. I hope you did not eat it. I am sure it would make you sick.

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