Fermented Kohlrabi Sauerkraut (Simple Lacto-Fermentation Recipe)

Kohlrabi belongs to the same brassica family as cabbage. It ferments using the exact same process — lacto-fermentation — and produces a sauerkraut that’s tangier, crunchier, and slightly sweeter than traditional cabbage sauerkraut.

If you’ve ever made sauerkraut from cabbage, you already know how to make this. If you haven’t, the process is almost absurdly simple: shred kohlrabi, add salt, pack it tight, wait. The beneficial bacteria already living on the vegetable do all the work.

Why Ferment Kohlrabi?

Three reasons.

Probiotics. Lacto-fermentation produces lactic acid bacteria — the same beneficial microbes found in yogurt, kimchi, and kombucha. These support gut health, improve digestion, and may boost immune function. You don’t get these benefits from raw or cooked kohlrabi — only from fermentation.

Preservation. Fresh kohlrabi lasts a couple of weeks in the fridge. Fermented kohlrabi lasts months. If you grow kohlrabi or buy it in bulk during peak season, fermenting is one of the best ways to extend its life. For other storage methods, check out our guide on how to store kohlrabi.

Flavor. Fermentation transforms kohlrabi’s mild sweetness into something more complex — tangy, savory, slightly funky. It develops depth that raw kohlrabi doesn’t have. The texture stays crunchy, which is a major advantage over fermented cabbage, which tends to go soft over time.

Basic Fermented Kohlrabi Sauerkraut

This is the foundational recipe. It uses two ingredients: kohlrabi and salt. Nothing else.

Ingredients

• 2 pounds kohlrabi (about 4-5 medium bulbs)
• 1 tablespoon fine sea salt (roughly 2% of the kohlrabi’s weight by mass)

On salt: Use non-iodized salt. Table salt contains iodine and anti-caking agents that can inhibit fermentation and cloud the brine. Sea salt, kosher salt (without additives), or pickling salt all work. The amount matters — too little and harmful bacteria can grow; too much and the fermentation stalls. Stick to 2% by weight.

Equipment

• Large mixing bowl
• 1-quart wide-mouth glass jar (Mason jar works perfectly)
• Something to weigh the kohlrabi down: a small jar filled with water, a fermentation weight, or a zip-lock bag filled with brine
• Cheesecloth or a loose-fitting lid (not airtight at this stage)
• Cutting board and knife, or food processor with shredding disc

Instructions

Step 1: Peel and shred the kohlrabi.

Peel thoroughly — remove the outer skin and the fibrous layer. The woody fibers won’t soften during fermentation and create an unpleasant texture.

Shred the peeled kohlrabi using a box grater (large holes), food processor with a shredding disc, or mandoline set to matchstick cut. You want thin shreds — roughly the same size as shredded cabbage for traditional sauerkraut. Thinner shreds ferment faster and produce more brine.

Step 2: Salt and massage.

Put the shredded kohlrabi in a large bowl. Sprinkle the salt over the top and toss to distribute.

Now the important part: massage the salt into the kohlrabi with your hands. Squeeze, press, and knead it firmly. This breaks down cell walls and draws out the natural juices. Kohlrabi is denser than cabbage and requires more aggressive massaging — expect to spend a solid 8-10 minutes. You’re done when the kohlrabi has visibly wilted and there’s a pool of liquid at the bottom of the bowl.

If the kohlrabi isn’t releasing enough liquid after 10 minutes of firm massaging, let it rest for 30 minutes and try again. Sometimes it needs time for the salt to work via osmosis.

Step 3: Pack the jar.

Transfer handfuls of the salted kohlrabi into your jar, pressing down firmly with your fist or a wooden spoon after each addition. You want to eliminate air pockets and submerge the shreds in their own brine.

Once all the kohlrabi is in the jar, press down hard one final time. The brine should rise above the surface of the shreds. If it doesn’t quite cover, dissolve 1/2 teaspoon salt in 1/4 cup water and add just enough to cover.

Step 4: Weight it down.

Place your fermentation weight, small jar, or brine-filled bag on top of the kohlrabi to keep it submerged. This is critical — any kohlrabi exposed to air above the brine line can develop mold. Everything must stay below the liquid.

Step 5: Cover loosely.

Cover the jar with cheesecloth secured with a rubber band, or use the Mason jar lid placed on top without tightening it. Fermentation produces CO2 gas that needs to escape. An airtight seal will cause pressure to build up.

If you have an airlock lid designed for fermentation, use that — it lets gas out without letting air (or bugs) in.

Step 6: Ferment.

Place the jar on a plate (to catch any overflow) in a spot that’s room temperature — ideally 65-75°F (18-24°C). Avoid direct sunlight.

• Days 1-2: You should see bubbles forming. This is good — it means fermentation has started. Press the kohlrabi down daily to keep it submerged.
• Days 3-5: Bubbling increases. The brine may turn cloudy. This is normal and expected.
• Day 5-7: Start tasting. Use a clean fork each time. The kohlrabi should taste tangy and pleasantly sour.
• Day 7-14: The sourness intensifies. Stop fermenting when it reaches your preferred level of tanginess.

Warmer temperatures (above 75°F) speed up fermentation — it may be ready in 5-7 days but can develop off-flavors if it goes too fast. Cooler temperatures (below 65°F) slow it down — it may take 2-3 weeks but generally produces a cleaner, more complex flavor.

Step 7: Store.

When the flavor is where you want it, screw the lid on tight and move the jar to the refrigerator. The cold temperature slows fermentation to a crawl, effectively preserving the current flavor for months. Fermented kohlrabi keeps in the fridge for 4-6 months, sometimes longer.

Flavor Variations

The basic recipe is excellent on its own, but you can add ingredients at the salting stage to create different flavor profiles.

Kohlrabi Sauerkraut with Caraway Seeds

The classic sauerkraut addition. Add 1 tablespoon caraway seeds to the kohlrabi during the salt massage. The seeds soften during fermentation and release their anise-like flavor throughout.

Spicy Kohlrabi Kraut

Add 1-2 teaspoons red pepper flakes and 2 cloves minced garlic during the salting stage. This pushes it toward kimchi territory while staying simpler than a full kimchi recipe.

Kohlrabi and Apple Sauerkraut

Shred 1 large tart apple (Granny Smith works well) and add it to the kohlrabi before salting. The apple adds natural sweetness that balances the sourness. It also introduces extra sugars that can speed up fermentation — check it a day or two earlier than usual.

Kohlrabi, Ginger, and Turmeric

Add 1 tablespoon grated fresh ginger and 1 teaspoon grated fresh turmeric during salting. The result is a golden-colored, warming sauerkraut that’s excellent alongside Asian-inspired dishes.

Mixed Brassica Sauerkraut

Use half kohlrabi and half green cabbage. This is a good starting point if you’re used to traditional sauerkraut — the cabbage provides the familiar flavor and texture while the kohlrabi adds crunch and sweetness.

Troubleshooting

The kohlrabi isn’t releasing enough brine. Kohlrabi is denser than cabbage and has less water. More vigorous massaging helps, but some batches need help. Make a 2% salt brine (1 teaspoon salt dissolved in 1 cup water) and add just enough to cover the shreds in the jar.

White film on the surface. This is likely kahm yeast — a harmless (but unappetizing) yeast that forms on the surface of ferments. Skim it off with a spoon. It won’t ruin the ferment as long as the kohlrabi below the brine smells and tastes normal. Better weight management and keeping everything submerged prevents this.

Pink or black mold. Unlike kahm yeast, actual mold (fuzzy, pink, black, or green) means something went wrong. If mold has only formed on the surface and hasn’t penetrated into the brine, you can remove the top layer generously and the rest is usually fine. If the entire jar smells off or the mold is throughout, discard it. This almost always results from kohlrabi being exposed above the brine line.

It’s too salty. You added too much salt, or it hasn’t fermented long enough. Give it more time — as lactic acid develops, it balances out the saltiness. If after 2 weeks it’s still too salty, you can rinse the finished kraut before eating, though you’ll lose some probiotics in the process.

It’s not sour enough. Either it hasn’t fermented long enough (give it more time) or your environment is too cold (move it somewhere warmer). If it’s been 3+ weeks at room temperature and still isn’t sour, the salt ratio may be off — too much salt inhibits the bacteria.

The texture is mushy. This usually means the kohlrabi was over-shredded (too fine), fermented too long, or fermented at too high a temperature. For crunchier results, shred slightly thicker and ferment at the cooler end of the range (65-68°F).

Serving Ideas

Fermented kohlrabi sauerkraut works anywhere traditional sauerkraut does, plus some places it doesn’t.

On sausages and hot dogs. The classic. Kohlrabi kraut is crunchier than cabbage kraut, which adds a nice textural contrast.

In grain bowls. A few forkfuls of tangy kraut on top of a rice or quinoa bowl with roasted vegetables and protein. The acidity cuts through heavier components.

On sandwiches. Reuben-style sandwiches, pulled pork, or any hearty sandwich benefits from the tang and crunch.

As a side dish. A small bowl alongside roasted meats, especially pork. German-style kohlrabi preparations pair naturally with sauerkraut.

Straight from the jar. When a craving for something tangy and crunchy hits. No shame in it.

In salads. Toss a couple tablespoons into a green salad for tang and probiotic benefits.

On tacos. Kohlrabi kraut works surprisingly well on fish tacos or pulled pork tacos. The acidity plays the same role as pickled onion or cabbage slaw.

Nutrition Benefits of Fermented Kohlrabi

Fermentation doesn’t just preserve kohlrabi — it enhances it.

Increased bioavailability. Fermentation breaks down cell walls and reduces anti-nutrients, making vitamins and minerals more accessible to your body.

Probiotic content. A serving of properly fermented kohlrabi contains billions of beneficial bacteria — comparable to a probiotic supplement. These are live organisms, so don’t heat your sauerkraut if you want the probiotic benefits. Add it to dishes after cooking, not during.

Preserved vitamin C. Kohlrabi is already high in vitamin C, and lacto-fermentation preserves most of it. Historically, sauerkraut was used to prevent scurvy on long sea voyages for exactly this reason.

Low calorie, high fiber. Fermentation doesn’t add calories. The fiber remains intact. It’s one of the most nutrient-dense condiments you can make.

Fermented kohlrabi is one of those foods that sounds more complicated than it is. Two ingredients, one jar, a week of waiting. The result is a probiotic-rich, crunchy, tangy condiment that lasts months and improves everything you put it on.