Can You Freeze Sauerkraut?

There’s a better question than, “Can you freeze sauerkraut?” (You can freeze just about anything.) The better question is, “Why would you freeze sauerkraut?”

Thinking about that might bring up memories of many nasty surprises we’ve found in our refrigerators, a fate we wouldn’t want for our sauerkraut: Extra beans from a forgotten evening of tacos now covered with a grey-blue mold; a pint carton of whipping cream that has turned to some kind of dubious cheese; jars of condiments that have been in the fridge so long they make you wonder what the manufacturers do to them to make them last for years.

So the answer to “Can you freeze sauerkraut?” might be “Sure. You could guarantee it stays fresh that way.” But hold on. Freezing stops probiotic sauerkraut’s diverse mix of health-promoting bacteria cold. Locks them up tight. Even kills off some of them. And the fresh, crunchy-chewy texture of sauerkraut can turn flabby when thawed out, as freezing expands the liquid in the fermented cabbage cells, rupturing them. The result is a rubbery and unappealing texture.

Why You Shouldn't Freeze Sauerkraut

Freezing will prevent spoilage organisms from invading your sauerkraut, but sauerkraut already has natural and very effective systems for preventing spoilage built in without having to be frozen.

Sauerkraut that’s alive with beneficial bacteria is not a product that will succumb to spoilage organisms. Its rich mix of living microorganisms produces a flood of lactic acid that allows the growth of healthy microorganisms and suppresses the growth of spoilage organisms. It’s that protective acid—about 2 percent in sauerkraut that’s finished fermenting—that gives the product the tang that people love so much. It improves the kraut’s digestibility. It renders its vitamins and minerals more biologically available. And as the sauerkraut ages, the populations of probiotic bacteria that stimulate your microbiome and enhance your immune system (and don’t we all need that right now in this time of pandemic?) pass through a series of stages that only improve flavor and bioactivity.

[See our post on How Long Does Sauerkraut Last?]

As the lactic acid builds up during fermentation, spoilage organisms simply die off. The acidic environment destroys them even as it enhances human health. That’s why people have been fermenting cabbage for eons, enjoying its taste, and benefitting from its health-giving properties.

Lactic acid bacteria occur naturally in universal abundance around the world. Archeologists have found evidence of cabbage fermentation as early as the 4^th Century BCE in China. In Korea, farmers have been fermenting cabbage and other vegetables in jars sunk into the cold ground, making kimchi, starting around the 1^st Century BCE.

Dr. Bibek Ray, professor of microbiology and food safety at the university of Wyoming and the author of Fundamental Food Microbiology, 5^th edition (Taylor & Francis Publishers), writes, “During natural fermentation, initial populations will be very high of Lactococcus and Leuconostoc bacteria; as the fermentation progresses and acidity reaches above the 1 percent level, these two species start to die off and Lactobacillus brevis takes over; as the acidity reaches 1.5 percent, this also starts dying and Pediococcus plantarum takes over to bring acidity to 2 percent in the final stage. So properly fermented (naturally) good quality sauerkraut, with a desirable clean acid flavor, mostly contains Lactobacillus brevis and Pediococcus plantarum… Freezing will enhance the killing process” of these two important probiotic species of healthy microbes.

So, can you freeze sauerkraut? Yes, but doing so damages many of the health benefits provided by the living probiotics in the food. Some people can sauerkraut, but that kills off all the probiotics and beneficial enzymes, rendering the food lifeless.

By far, the best way to store your sauerkraut is to keep it in the fridge. A typical fridge operates at from 35 to 40 degrees Fahrenheit, a cold temperature that slows the living probiotic organisms almost to a stop. The acid environment of the kraut prevents spoilage. And sources report that sauerkraut keeps perfectly well in the fridge for a year or two. One source said she kept a jar in the fridge for six years, just to see what would happen. Her finding? Not much, other than the kraut lost its fresh, raw crunchiness.

We at wildbrine encourage you to enjoy your probiotic-rich sauerkraut long before a year or two. We have more waiting for you at the market, no worries.

About the Author: Sonoma County resident Jeff Cox is the author of 24 books, including The Essential Book of Fermentation (Avery, 2013)