How Long Sauerkraut Lasts in the Refrigerator and How to Keep It Fresh

Unopened sauerkraut lasts 4 to 6 months in the refrigerator

An unopened jar of sauerkraut will stay safe to eat for 4 to 6 months in your refrigerator, sometimes longer. The exact timeline depends on how it was made and stored before you bought it. Commercial sauerkraut is pasteurized (heated to kill bacteria), so it has a longer shelf life than raw, fermented sauerkraut you might make at home or buy from a farmer's market.

The cold temperature slows down any remaining microbial activity, but sauerkraut's natural acidity—created during fermentation—is what really preserves it. That acidic environment makes it hostile to the bacteria that cause spoilage. As long as the jar stays sealed and you keep your refrigerator at 40°F or below, the sauerkraut remains stable well past the printed date.

Key Takeaways

• Unopened sauerkraut lasts 4 to 6 months in the refrigerator; opened jars last 1 to 3 months if kept submerged in brine.
• Raw, unpasteurized sauerkraut ferments continuously in the cold and may develop stronger flavor or cloudiness over time, which is normal.
• Once opened, keep the sauerkraut covered with brine and use a clean utensil each time you remove some, to prevent contamination.
• Signs of spoilage include mold on the surface, a foul smell (different from normal sour fermentation), or sliminess; discard if you notice these.
• Homemade sauerkraut stored in a sealed jar lasts 4 to 6 months if kept submerged in brine and refrigerated immediately after fermentation.

Opened sauerkraut lasts 1 to 3 months if kept submerged

Once you open a jar, sauerkraut's shelf life shortens to 1 to 3 months. The moment air enters the jar, you expose the sauerkraut to oxygen and the bacteria in your kitchen. The brine—the salty liquid the sauerkraut sits in—is your main defense. That liquid keeps oxygen away from the cabbage and maintains the acidic environment that prevents spoilage.

Always keep the sauerkraut submerged under the brine. If pieces float above the surface, they can dry out and become vulnerable to mold. Use a clean fork or spoon every time you remove sauerkraut from the jar; never use your fingers or a utensil that has touched other foods. This habit prevents cross-contamination and extends the jar's life significantly.

Store the opened jar on a shelf in the main body of your refrigerator, not in the door. Door shelves experience temperature fluctuations every time you open and close the fridge, which speeds up fermentation and degradation. A stable, cold shelf keeps the sauerkraut fresher longer.

Raw and pasteurized sauerkraut age differently

Pasteurized sauerkraut (most store-bought brands) has been heated to kill live bacteria. This makes it shelf-stable for longer and stops fermentation entirely. Once refrigerated, it stays relatively unchanged for months. The flavor and texture remain consistent because no active fermentation is happening inside the jar.

Raw, unpasteurized sauerkraut contains live beneficial bacteria (lactobacillus) that continue to ferment slowly in the cold. Over time, you may notice the sauerkraut becomes softer, the brine cloudier, or the flavor more intensely sour. These changes are normal and safe—they are signs of continued fermentation, not spoilage. The cloudiness is usually yeast or bacteria, harmless and common in fermented foods. If you prefer milder flavor and firmer texture, use raw sauerkraut sooner rather than later.

Check the label or ask at the farmer's market whether your sauerkraut is raw or pasteurized. Raw versions are often labeled "unpasteurized," "live culture," or "raw fermented." They are more perishable but offer the probiotic benefits that fermentation creates.

How to tell if sauerkraut has gone bad

Sauerkraut is acidic and fermented, so it naturally smells sour and tangy. That is not a sign of spoilage. What you are looking for is a foul or rotten smell—something that makes you recoil, distinctly different from normal fermented sauerkraut. If the smell is off, discard the jar.

Visible mold is another clear sign to throw it out. Mold appears as fuzzy growth, usually white or greenish, on the surface or sides of the jar. A small amount of white film (kahm yeast) on top of raw sauerkraut is harmless and can be skimmed off, but fuzzy mold means the jar is compromised.

Sliminess is the third warning sign. If the sauerkraut feels slimy or mushy rather than crisp, and the brine looks thick or ropy, bacteria have broken down the cabbage's cell structure. This happens when the jar has been exposed to warmth or contamination. Discard it. Trust your senses: if something looks, smells, or feels wrong, it is safer to throw it away than to risk foodborne illness.

Storing homemade sauerkraut in the refrigerator

Homemade sauerkraut follows the same refrigerator rules as store-bought, but timing matters more because you control when fermentation stops. After fermenting on the counter for 3 to 10 days (depending on room temperature and how sour you like it), transfer the jar to the refrigerator. The cold dramatically slows fermentation, essentially pausing it. At this point, your homemade sauerkraut will last 4 to 6 months if kept sealed and submerged in brine.

Make sure the sauerkraut is fully submerged in brine before you refrigerate it. If you fermented it in a crock or wide jar, transfer it to a narrower container with a tight-fitting lid so the brine covers everything. Oxygen exposure is the biggest threat to homemade sauerkraut because it lacks the pasteurization that commercial versions have.

Label the jar with the date you moved it to the refrigerator. This helps you track how long it has been stored and reminds you to use it within a reasonable window. Even though it may be safe for months, the flavor and texture are best within the first 2 to 3 months of refrigeration.

Organizing your refrigerator to protect sauerkraut

Sauerkraut does best on a middle or lower shelf where temperature is most stable. The back of the shelf is colder than the front, so place the jar toward the back if your refrigerator has hot spots near the door or front. Keep it away from the freezer compartment, which can cause temperature swings.

Store sauerkraut away from strong-smelling foods like onions, garlic, or fish. Although the jar is sealed, prolonged exposure to pungent odors can affect the flavor over time. Keep it separate from raw meats and seafood as well, both for flavor protection and to prevent any cross-contamination if a jar accidentally leaks.

If you have multiple jars, use the oldest one first. Rotate them so nothing sits forgotten at the back of the shelf for a year. Even though sauerkraut is stable, its quality declines gradually, and you will enjoy it more if you use it while it is fresher.

Frequently Asked Questions

Can I freeze sauerkraut to make it last longer?

Yes, you can freeze sauerkraut, and it will last 8 to 12 months in the freezer. However, freezing breaks down the cabbage's cell structure, so it will be softer and mushier when thawed. Frozen sauerkraut works well in cooked dishes like stews, braises, or sauerkraut and pork, but not as a crisp side dish or topping. Thaw it in the refrigerator before using.

Is the white film on top of my sauerkraut safe to eat?

The white film is usually kahm yeast, a harmless byproduct of fermentation. You can skim it off with a clean spoon and discard it. It does not make the sauerkraut unsafe, but removing it keeps the jar cleaner and prevents it from spreading. If the film is fuzzy or has any color other than white, it is mold and the jar should be discarded.

Why did my sauerkraut get softer after I opened it?

Raw sauerkraut continues to ferment slowly in the refrigerator, which softens the cabbage over time. Pasteurized sauerkraut should stay firm because fermentation has stopped. If pasteurized sauerkraut softens quickly, it may have been exposed to warmth or contamination. Check the smell and appearance; if anything seems off, discard it.

Can I store sauerkraut in a container other than glass?

Glass is best because it does not react with the acidic brine and does not absorb odors. Plastic containers work but may stain or retain smell over time. Metal containers should be avoided because the acid can corrode them and affect the flavor. If you transfer sauerkraut to a new container, make sure it is food-grade and has a tight-fitting lid.

How do I know if my homemade sauerkraut fermented long enough?

Taste it. If it is sour enough for your preference, it is done fermenting. There is no single "correct" fermentation time; it depends on room temperature and your taste. Cooler kitchens take longer (7 to 10 days); warmer ones ferment faster (3 to 5 days). Once it tastes right, refrigerate it to stop fermentation and preserve it.