Vegetable Fermentation Further Simplified

Excerpted from The Revolution Will Not Be Microwaved

A head of cabbage forgotten on an obscure shelf of your pantry will not spontaneously transform itself into sauerkraut. Vegetables left exposed to air start to grow molds, and if left long enough, those molds can reduce a head of cabbage to a puddle of slime, bearing no resemblance whatsoever to crunchy, delicious, and aromatic sauerkraut.

The simple key to successful vegetable fermentation is to make sure your vegetables are submerged in liquid. That’s it, the big secret. Usually the liquid is salty water, also known as brine, but fermentation can be done without salt, or with other liquids, such as wine or whey. Typically, when fresh vegetables are chopped or grated in preparation for fermentation—which creates greater surface area—salting pulls out the vegetable juices via osmosis, and pounding or tamping the vegetables breaks down cell walls to further release juices, so no additional water is required. However, if the vegetables have lost moisture during long storage, occasionally some water is needed; if brine hasn’t risen to submerge the weighted vegetables by the following day, add a little water. In the case of vegetables left whole (cabbage heads, cucumbers, green tomatoes, string beans, okra, zucchini, eggplant, peppers—try anything), the vegetables should be submerged in brine.

The huge variety of vegetable ferments you can create all exist along the spectrum from shredded and salted to whole and submerged in a brine. Sometimes you use elements of each style, as in kimchi recipes that call for soaking vegetables in a brine to soften them and leach out bitter flavors, then pouring off excess brine and mixing in spices. In some cases the liquid is what we’re after, flavored by the vegetables and fermentation.

Pretty much any vegetable can be fermented. Use what is abundantly available and be bold in your experimentation. Seaweeds are a wonderful addition to ferments, as are fruits, though mostly fruit ferments go through their process very quickly. I’ve even made delicious sauerkraut with mashed potatoes layered in with the salted cabbage, as well as kimchi with sticky rice layers. The sharp fermented starches are delicious. The spicing of vegetable ferments is quite varied, too. Kimchi typically includes red chili peppers, garlic, ginger, and scallions. Sauerkraut might include caraway seeds (my favorite), juniper berries, apples, or cranberries. New York–style sour pickles are spiced with dill, garlic, and sometimes hot peppers. To keep cucumbers crunchy, add to the brine some grape leaves or leaves of horseradish, oak, currant, or cherry.

How much salt do you use? Traditionally vegetables have been fermented with lots of salt. In addition to pulling water from the vegetables, salt hardens pectins in the vegetables, rendering them crunchier, and discourages the growth of bacteria other than lactobacilli. By inhibiting competing bacteria, salt enables the vegetables to ferment and to be stored for longer periods of time. Since preservation has historically been one of the important motivations for fermentation, ferments have tended to be quite salty. But for health-conscious people interested primarily in flavor and nutrition, less salt can be better. Salt lightly, to taste. It is easier to add salt than to take it away, but if you oversalt, you can dilute by adding water and/or more vegetables. There is no magic proportion of salt the process requires—it’s just personal preference. As a starting point, try 3 tablespoons of salt per 5 pound of vegetables. More salt will slow the fermentation process; less (or none) will speed it up. Ferments with less salt may be more prone to surface molds. You can leave out the salt or use various mineral-rich substitutes such as celery juice (my favorite salt-free variation) or seaweed. Just be sure the vegetables are submerged in the liquid.

Some people promote the idea that salt-free sauerkrauts contain more beneficial organisms than salted krauts. I don’t believe that. The most specific beneficial bacteria we’re after, Lactobacillus, is salt-tolerant and abundantly present even in salty krauts; arguably, salt-free ferments are more biodiverse, but this diversity often results in mushy textures. Though it is possible to ferment vegetables without salt, a little salt results in far superior flavor and texture—and just as much beneficial bacteria. So again, salt to taste.

What kind of vessel should you use to hold your ferment? Avoid metal, as salt and the acids created by fermentation will corrode it. Heavy ceramic cylindrical crocks are the ideal fermentation vessels, though they can be hard to find and expensive. Glass containers work well, especially those with a cylindrical shape or with a wide mouth, and so do nesting bowls. Crock pots with ceramic interiors make effective fermentation vessels and can often be found in thrift stores. In a pinch, you can use plastic, but even food-grade plastics leach toxic chemicals.

The reason a cylindrical shape is desirable is for ease of weighting down the fermenting vegetables to keep them submerged rather than floating to the top. I generally use a plate that just fits inside the vessel, weighted down by a full jug of water, and I drape a cloth over the top of the vessel to protect against flies. I call this the “open-crock” method. Containers in other shapes can work with improvisation, or you can manually press the vegetables to submerge them in the liquid.

If the vegetables float to the top and remain exposed to air, they are likely to develop mold. Sometimes, especially in hot weather, your ferment may develop a film of white mold on its surface. This is very common and will not hurt you or the kraut. Scrape off the mold as best you can, don’t worry about particles that mix into the vegetables, and enjoy the delicious ferment beneath. Specially designed Harsch crocks eliminate this problem by creating an oxygen-free airspace around the ferment. These German crocks are elegant but expensive. Another way to avoid mold is by weighting the ferment in the vessel with water contained in a double layer of plastic bags. The water will spread to cover the entire surface, protecting it from aerobic surface molds. The downside of this method, of course, is that your food comes into prolonged contact with plastic, which leaches chemicals into the food. I prefer to use the open-crock method and remove mold as necessary.

Whatever type of vessel you use, pack the vegetables into it with some force (unless they are whole), in order to break down cell walls and release juices. I use a blunt wooden tamping tool. You can improvise with a piece of wood or your fist, or you can manually massage and squeeze the vegetables, as described in the recipe for massaged kale (see page 185). Once the vegetables are weighted down, the salt will continue to pull moisture from the vegetables for many hours yet. If, by the following day, the vegetables are not submerged, add a little water.

How long do you ferment the vegetables? I wish I had an easy answer to this question. “Ferment until ripe,” many recipes advise, but ultimately you will have to decide when it is ripe. Sour flavor—from lactic acid—develops over time. Longer fermentation translates to tangier flavor. This happens more quickly in warm temperatures than in cool ones. If you start your ferment at harvest time, in the autumn, as temperatures are dropping, it can ferment for six months or longer. This is how people survived before refrigeration and globalized food. Many people, however, prefer the flavor of a mild ferment to that of a strongly acidic one. When you are first experimenting, taste your ferments early and often. Serve some after three days, then three days later, and again three days after that. Familiarize yourself with the spectrum of flavors that fermentation can create and see what you like.


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109 thoughts on “Vegetable Fermentation Further Simplified

  1. thanks for the information it is right on and very important for me to learn how to do i am excited to start. sooo many books and info out there hard for me to decide on where to start. i am retired and on a limited income. so for buying books one or two is all i could afford if that thanks a lot (i know you care)those who do for others are my HERO,S

  2. After following your You Tube video and other sources I made my first batch of sauerkraut a couple months ago and it came out fine. We ate all of it. This past week I tried it again. It is day 5 of the fermentation but I am concerned about its strong odor. I’m not sure if the odor indicates that it went bad or not. I wonder if it is because of the warmer weather. I think I did everything right and the cabbage was fresh. How do I know if it is safe?

    • There has never been a single case of food poisoning reported in the United States from fermented vegetables. No need to worry about safety.

    • In summer my sauerkraut takes 5 days to ferment. In winter it takes longer. You can open the jar at any time, so it’s easy to get the fermentation that you want.

      Sometimes, one bacterial strain will dominate in the fermentation, and give the sauerkraut a particular aroma, but give it a few days and another will take over and give it the taste and smell you want. It’s ALIVE!

  3. I tasted home made saurkraut this week and loved it so I wanted to make some. I used purple cabbage, a few jalapeno slices, sprinkled with ceyenne pepper, lots of himalayan pink salt in a big large mouth glass jar. I followed all of the directions and wonder if I can wait 3 whole days! I’m in central Texas where the temps are in the 90s. My kraut jar is in the kitchen which is the warmest room. Should I mmove it to a cooler room? So excited! I’m hoping it has a sweet but spicey crunhy taste. I saved your directions,.

  4. LOVE IT !! I’m finding great fun and creativity in concocting variations; red cabbage-beet-carrot; chard-spinach-daikon; radish-grapeleaf; bokchoy-red jalapeno-kale; cabbage-red bellpepper-cauliflur-garlic; green & yellow zuccini-purple onion; and more. Select what to serve by the color I want to add to plate. would kefir water act as culture? or be valuable addition?
    THANKS for turning me on to this !!!!
    & Namaste

  5. I appreciate your help in people becoming more healthy and in helping them taking control of their future well being.
    Again, Thanks!
    Bernard Deku

  6. Is it advisable to use the lids that came with glass jars? ie; I eat a lot of peanut butter and have tons of jars. As long as the veggies don’t come into contact with the metal, it should be ok, right??

  7. Hi, not sure why my question was erased…I need to know if I should throw my batch of sauerkraut out after using a metal masher to help pound the brine out? It seems to be fermenting well but I don’t want to poison myself!

  8. 06/22/2012

    Cabbage must be submerged in liquid brine solution. For how many days? before you can start eating the fermented cabbage? Do I need to apply salt and squeeze in motion so that juice will come before putting in a jar? Or not necessary to squeeze? Salty foods are not good for kidney? Per gallon of water or wash rice water, what weight of sea salt in gram should I use? The same number of days before I can start eating?

    • Best to squeeze and get veggies juicy before putting it in the jar. Salt lightly, to taste. Generally no need to add water to sauerkraut; squeeze juice out of the veggies. You can ferment two days, two weeks, two months, or longer, depending on what flavors you like. Taste at frequent intervals so you can figure out what you like.

  9. I recently heard an interview Sandor gave on the survival podcast with Jack Spirko that offered information about the process of fermenting and its health benefits in a simple, straight forward yet highly effective nature. Now I’m anxiously waiting to taste my first batch of fermented cucumbers and wanted to say thank you for taking the time to make a positive difference in my life and let others know that it really is simple to get started.

  10. I have attempted sauerkraut several times. The cabbage was always above the brine at the end and I didn’t know if this was ok. I needed to know if I should add brine or if exposure to air after a day or two was ok. Finding the answer to this question was very frustrating because teachers only discuss how to begin the ferment and don’t discuss the final product. Thank you for answering this question!

    • It’s best to keep your veggies submerged. If they are not submerged, they are prone to oxidation and surface growth of yeasts and molds. Pound or squeeze veggies to get them juicy before stuffing into crock; keep weighted down; add water if necessary due to evaporation. And if the kraut on top is dry and exposed to air when you harvest, discard that top layer. What’s beneath it protected will be fine.

  11. I love my sauerkraut, but then, I tried fermenting carrot slices and mushrooms in some of the sauerkraut juice. It worked, and I liked the flavor, but not the mushy texture.

    I don’t want to just keep adding more salt to keep the veggies crisp. So … I wonder — is there something unhealthy about calcium chloride (or calcium hydroxide, food grade lime, “hydrated lime,” “pickling lime” etc.)? Thank you for any info on this!

  12. I’m new to the fermenting process and it seems sooooo easy. I live in Costa Rica where it’s hot all the time so the process is fast. I tried a small batch of sauerkraut in a plastic container with a water filled plastic bag to keep it covered and it was perfect after 4 days! I started a second batch. Then I started pickles. I can’t find pickling size cucumbers, so I just bought the smallest I could find, cut them in half and then quartered them lengthwise. I don’t have another proper container, so I just used a plastic bag. I works really well. I just squeeze out air and built up gasses every day so that the pickles stay immersed. They taste great after 3 days, but the brine is cloudy. Is that a concern? Thanks for a super site!

  13. Thank you so much for your great recipe and how to make sauerkraut and other fermented veges! This is so valuable for our health and we appreciate the shared knowledge!
    How nice that there are still some people that give their knowledge for free!
    Can’t wait to make the recipe – do we add spices during fermentation or at time of degustation?
    love&light cécile

  14. My question is about ingesting or not of the brine. It is too salty for me. I do squeez it out as much as I can, have even washed the brine out of the vegetables. If I do that, will I sacrifice all the benefits of fermentation?

  15. Thanks for this great article. I hate mushy and love salty so salt in my ferments works great.
    I love the clarity …you know the questions people ask!

  16. We talk a lot about the danger of bacterium Clostridium botulinum in the canning process. Why is the no bacterium Clostridium botulinum in the fermentation process and the are some in the canning process? If I put salt in my canning should it stop the danger?

    • There are two important differences: When the veggies are raw, other bacteria, notably lactic acid bacteria, which can grow in the presence of oxygen (unlike C. botulinum) easily dominate, and as they acidify the environment, they destroy C. botulinum. Also, canning creates a perfect vacuum and wipes out the competition, because C. botulinum can tolerate higher temps than most other bacteria.

  17. Can organic frozen veggies be successfully fermented, perhaps brought to room temperature then crushed up with some salt? Is there enough lactobacilli on there to get a tasty ferment going?

  18. Hi,
    it is my second batch, this one with black radishes with sea salt. After the first week it was reall nice but maybe not enough fermented, so I let it 5 days more, and i open the crock and it smells like hell, but the veggies were not so bad except that there were in very gluing liquid.
    I washed the vegetables but I don’tknow if we can eat them.
    What do you think?

    • No need to worry about danger. If you let them ferment longer, that gluey brine will probably go away. It’s generally an in-between stage that passes.

    • Because minerals are so bioavailable in kraut and many other fermented foods, the net effect of eating them is alkalinizing, even though they are acidic.

  19. Appreciate you comments about salt. I’ve had some problems with this before. However, when the temperature is high more salt seems to prevent veggies becoming mushy. Salt seem to help preserve the crunchiness of the veggies.

    Thanks for a nice site.

  20. Thanks for a very informative post. I’ve been fermenting vegetabls for some time and tried many recipes. But your experience is valuable and I use many of you good suggestions.

  21. Want to start fermenting BUT . . .was wondering how much (if any)alcohol is produced during the process. – -Thank You, John

  22. Last summer I made my first batch of fermented pickles after having made vinegar/brine pickles for a couple years.

    The fermented version was an interesting departure from the quick dills we have enjoyed. I bought a 4 gallon Ohio Stoneware crock, and two “stones”, lined the bottom with feral grape leaves off the back fence, and loaded in fresh dill, lots of garlic and peppercorns, then piled in cukes I had been stockpiling in the fridge.

    I’m unable to find the answer elsewhere, and you are the guru, so here’s the question; since I’m using cucumbers fresh off my vines, I have a rolling harvest. Can I begin my ferment with a first batch of a baker’s dozen cukes (a week’s worth at this point) and add fresh cukes as they come off the vine? This because from all accounts, fresh produce yields best results. Last year I started losing fridge-stored cukes before I felt I had enough to begin the ferment.


    • The problem can be that older ones start to get soft and mushy while younger ones are still crispy, and make the fresher ones soften faster. i’ll often do for a shoer time, over a week, say, and start harvesting the early ones first. another issue is the salinity will go down with each batch added, so you need to add some salt to compensate. Good luck and enjoy!

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