Sauerkraut juice is simply the tangy, salty brine that forms naturally when you ferment cabbage with salt. You don’t need a juicer or any special equipment. The process is the same as making sauerkraut itself: salt draws liquid out of shredded cabbage, beneficial bacteria ferment that liquid over a few weeks, and the resulting brine is your sauerkraut juice. You can also get more juice from an existing batch by straining finished sauerkraut or pressing the solids.
What You Need
The ingredient list is short: one medium head of green cabbage (about 2 pounds) and 1 to 1.5 tablespoons of non-iodized salt. Iodized table salt can inhibit the bacteria responsible for fermentation, so use sea salt, pickling salt, or kosher salt instead.
For equipment, you need a large mixing bowl, a wide-mouth glass jar or ceramic crock, something to weigh the cabbage down (a smaller jar filled with water works), and a clean cloth or loose lid to cover the top. A wooden tamper or the end of a rolling pin helps with packing, but clean hands work fine.
Step-by-Step Fermentation
Remove the outer leaves of the cabbage and set one aside to use later as a cover. Quarter the head, cut out the core, and shred the rest into thin strips. Toss the shredded cabbage with salt in a large bowl, then let it sit for 5 to 10 minutes. This resting period wilts the cabbage slightly and starts pulling water from the cells.
After resting, massage and squeeze the cabbage with clean hands for 5 to 10 minutes. You’ll feel it soften and release liquid. Keep going until a pool of brine collects at the bottom of the bowl. This liquid is the foundation of your sauerkraut juice.
Transfer the cabbage and all the accumulated liquid into your fermentation jar. Press it down firmly with a tamper, spoon, or your fist until the brine rises above the surface of the cabbage. Every piece of cabbage should be submerged. If there isn’t quite enough liquid to cover everything, dissolve 1.5 tablespoons of salt in a quart of cooled boiled water and add just enough to top it off. Place the reserved cabbage leaf over the shredded cabbage as a cap, then weigh it down. Cover loosely so gas can escape.
Fermentation Time and Temperature
Room temperature drives the pace of fermentation. The sweet spot is roughly 65 to 75°F (18 to 24°C). Warmer temperatures speed things up but can produce softer, mushier kraut. Cooler temperatures slow things down and tend to develop a more complex, tangy flavor.
At typical room temperature, fermentation takes about 3 to 4 weeks. You’ll notice tiny bubbles forming within the first few days, which is a sign that lactic acid bacteria are active and producing carbon dioxide. Taste the brine periodically starting around day 7. When it’s pleasantly sour and tangy, with no raw-cabbage flavor left, your sauerkraut juice is ready. If you want maximum probiotic content and acidity, let it go the full 3 to 4 weeks.
Collecting the Juice
You have two options depending on how much juice you want. The simplest approach is to pour or ladle off the brine that sits on top of the finished sauerkraut. A standard 2-pound head of cabbage typically yields about 1 to 2 cups of brine this way.
If you want more, press the fermented cabbage through a fine-mesh strainer or squeeze it through cheesecloth over a bowl. This wrings out additional juice trapped in the solids. You can also blend some of the fermented cabbage with a bit of the brine in a blender and strain the result for a thicker, more concentrated juice.
What’s Actually in the Brine
Unpasteurized sauerkraut juice is rich in lactic acid bacteria, the same organisms that give it a sour taste. Research isolating bacteria from sauerkraut has identified several species, with viable counts in the range of 6 to 7 million colony-forming units per milliliter. That’s a meaningful dose of live microbes in every sip, comparable to what you’d find in many commercial probiotic supplements.
The juice also contains lactic acid, vitamin C from the cabbage, and a significant amount of sodium from the salt used during fermentation. One cup can easily contain 1,000 mg or more of sodium, so keep that in mind if you’re watching your salt intake.
How Much to Drink
Start small. Clinical observations suggest that about 1 tablespoon daily supports digestion and helps reduce constipation for many people. A study of 25 healthy volunteers found that larger amounts of sauerkraut juice inconsistently caused watery stool, and repeated high intake may lead to diarrhea. Begin with a tablespoon or two per day and increase gradually over a week or two as your gut adjusts. Most people settle comfortably into 2 to 4 tablespoons (1 to 2 ounces) daily.
Storage and Shelf Life
Once fermentation is complete, transfer the juice to clean glass jars and store it in the refrigerator. Cold temperatures put the live bacteria into a dormant state without killing them. They reactivate in the warmth of your digestive system after you drink it. Refrigerated, raw sauerkraut juice stays fresh and biologically active for 4 to 6 months. Keep the jar sealed between uses to prevent contamination, and always use a clean utensil when pouring.
Troubleshooting Common Problems
Not Enough Liquid
If your cabbage didn’t release enough brine to stay submerged, the shreds may have been too thick or the cabbage was older and drier. Add a small amount of salt brine (1.5 tablespoons salt per quart of cooled boiled water) to top it off. Going forward, shred the cabbage as thinly as possible and don’t skip the 5 to 10 minute resting period before you start squeezing.
White Film on the Surface
A white, grey, or slightly pink film on the surface is typically kahm yeast. It’s harmless but can give the brine an off flavor if left unchecked. Skim it off with a clean spoon, make sure the cabbage stays submerged, and continue fermenting. The juice underneath is still fine.
Green, Blue, or Black Spots
Mold is green, blue, brown, or black in color, and it looks distinctly fuzzy compared to the flat film of kahm yeast. If you see mold anywhere on your ferment, discard the entire batch. A healthy ferment smells pleasantly sour. A putrid or noticeably spoiled smell, especially combined with visible mold, means fermentation has failed.
Too Salty, Not Sour Enough
If the juice tastes overly salty after a week, give it more time. As lactic acid bacteria multiply, they produce acid that balances the saltiness. If after 3 to 4 weeks it still doesn’t taste sour, the fermentation environment was likely too cold or the salt ratio was too high. Try again with slightly less salt or move the jar to a warmer spot in your kitchen.