Preserving Vegetables With Lacto-Fermentation

Preserving vegetables using lacto-fermentation helps provide the best probiotics for your health.

Fermenting Vegetables

Shredding cabbage and carrots is the first step in fermenting vegetables.

Photo By iStockphoto/FotografiaBasica

Content Tools

Before ample freezers and nifty pressure canners came along, people preserved food through a variety of different means. One of these methods, still effective today, utilizes naturally occurring microorganisms to create a lactic acid rich environment — as in kraut — that slows down the decomposition process. We’re talking about lacto-fermentation.

In addition to preserving vegetables, the process of lacto-fermentation partially breaks them down and makes some nutrients more available for uptake. Take sauerkraut, for instance: Sauerkraut is renowned for its high level of readily absorbed vitamin C. Historically, vats of it were squirreled away in cold cellars for long northern winters, or carried on ships to help prevent scurvy.

Health-wise, many of the live probiotic cultures in lacto-fermented food complement the bacteria in our stomachs. If you have plenty of good bacteria, it’s a natural fighting force against pathogens, helping to maintain your health. Incorporating lacto-fermented foods into your diet can help support beneficial gut flora, and gives new meaning to intestinal fortitude.

Basic biology

Making lacto-fermented vegetables is easy, and since the process promotes and maintains a highly acidic environment in the fermentation vessel, there is virtually no risk for botulism poisoning, even though the process is carried out in the absence of oxygen.

Spores of the botulism toxin-producing bacterium, Clostridium botulinum, are found naturally on most vegetables. Though generally harmless, these spores can be harmful to infants and others with compromised immune systems. The real scare comes from storing foods in a low-acid, anaerobic (oxygen-lacking) environment that hasn’t been properly sterilized – which is what all the fuss is about with canning. Under these conditions, C. botulinum produces a deadly, odorless, tasteless toxin. The biology and physical conditions inside the fermentation vessel are neither conducive to C. botulinum growth, nor to toxin formation, all without heat sterilization.

Fermentation vessel

For fermenting, you need a non-metallic container and a way to keep the vegetables immersed in brine. This might be a crock with a weighted plate on top of the vegetables, a plastic food-grade bucket (although some people have issues with using plastic in this acidic process), or a glass jar. If you use something that has an open top (not ideal), such as an old-fashioned crock or jar, be sure you have a heavy cloth to place over it, or fashion a firm-fitting wooden top to keep out critters. Better yet, use specially designed fermentation vessels that help you keep the entire process safe and sanitary.

When I started fermenting, I bought a Harsch crock (similar models are available from Schmitt). It has a lip that holds water, which serves as a moat to create a seal of sorts, and a lid that allows the carbon dioxide produced by the fermenting veggies to escape by bubbling through the water, as well as stone weights to keep vegetables under the brine. They are relatively expensive, but I look at it as a long-term investment that is fairly foolproof.

Specially modified jars, such as those available from TheProbioticJar, are an inexpensive alternative to a crock and include a brewer’s airlock that helps prevent contamination during the fermentation process. Simply fill the jar with shredded vegetables, cover them with brine, seal the lid and insert the airlock.

Fermenting Vegetables: Inoculation

Lacto-fermenting of vegetables isn’t an exact science, and one of the most variable ingredients is salt. While you don’t have to use it, it is recommended to help retard the growth of undesirable microbes. Salt also helps draw out the moisture from the vegetables, and it slows down the fermentation process to some degree. You can use practically any kind, although non-iodized kosher or sea salt works particularly well.

You also can jump-start the growth of lactic acid-producing bacteria by supplying some live cultures at the beginning. You can make your own innoculum by straining plain, live-culture yogurt through cheesecloth for several hours. The liquid contains the cultures and will store in a jar in the refrigerator for up to several months. Alternatively, you can save some of the juice from your just completed, successfully fermented vegetables to help the next batch along.

Chop, pound and pack

There’s really no proper way to chop your veggies. I prefer to hand chop, primarily because I find that the smaller pieces from the food processor tend to float to the top of the brine. The little bits won’t ruin the batch, but I usually have to scrape them away since they have a greater tendency to mold. Floaters showing some mold growth can be removed and discarded without any danger to losing the batch.

Once you chop your vegetables, you need to release the moisture in the cell walls by crushing the vegetables. I use a potato masher, and many people use a handy wooden kraut pounder. It’s easier to do this in a big bowl or tub before placing the veggies in your fermenting container. This way you can see how much juice is being released.

After a thorough mashing, if you don’t have enough liquid from the vegetables to cover them by about an inch, you’ll need to add liquid.

Boil a small pan of non-chlorinated (chlorine will kill the microbes) water, allow it to cool, add a little salt (more to your taste preference than anything else), and pour it over your vegetables in the fermenting container.

Some folks simply pack their vegetables into the fermentation container and cover them with a brine solution. In some cases you might need to add weight to push the vegetables beneath the brine.

Let’s eat

To use the lacto-fermented vegetables, start by adding a little to your diet before a meal.

“If you get something fermented into a child or an adult once a day, it does so much for the immune system,” says my friend, Lynn Evans, who has been teaching fermenting classes for years.

She also warns if someone consumes too much without being used to it, it might cause a bit of stomach gurgling. This doesn’t mean it’s spoiled. It’s simply because your body isn’t used to it. Have a spoonful to start, and go from there.

Once you begin fermenting, you’ll soon find yourself adding a wealth of highly nutritious food to your menu.

Read More: Try out your technique with a Homemade Sauerkraut Recipe or a Gingered Carrots Recipe.


Amy Grisak is a freelance writer living in Montana, who encourages readers to grow their own vegetables for the best possible fermentation experience.