How Long Sauerkraut Stays Fresh in Your Refrigerator

Unopened sauerkraut lasts 4 to 6 months in the refrigerator, and opened jars last 1 to 2 months

The shelf life of sauerkraut depends on whether the jar has been opened and how it's stored. An unopened jar of store-bought sauerkraut will keep for 4 to 6 months in your refrigerator, sometimes longer if the seal remains intact and the brine stays undisturbed. Once you open it, the sauerkraut is exposed to air and bacteria from utensils, so it will last 1 to 2 months before the flavor deteriorates or mold appears.

Homemade sauerkraut fermented in a jar follows a different timeline. If it's still fermenting (actively producing bubbles), it can last several months in the refrigerator because the fermentation process itself preserves it. Once fermentation slows or stops, treat it like opened store-bought sauerkraut and use it within 1 to 2 months.

Key Takeaways

• Unopened store-bought sauerkraut stays good for 4 to 6 months in the refrigerator as long as the seal is unbroken and the brine covers the cabbage.
• Opened sauerkraut lasts 1 to 2 months once exposed to air, so cover it tightly after each use and always use a clean utensil to remove portions.
• Homemade sauerkraut that is still actively fermenting can last several months, but once fermentation stops, treat it as opened and use within 1 to 2 months.
• Signs that sauerkraut has gone bad include visible mold, a sour smell that turns rotten, slime on the surface, or a mushy texture instead of crisp.
• Store sauerkraut in the coldest part of your refrigerator, usually the back of a shelf or the bottom drawer, to extend its life.

Why the brine matters for storage

The brine—the salty liquid sauerkraut sits in—is what keeps it fresh. Brine is a natural preservative because salt draws water out of bacteria and mold, preventing them from growing. As long as the cabbage stays submerged under the brine, it is protected from air and contamination. If the brine level drops below the surface of the cabbage, the exposed parts will dry out, discolor, or develop mold.

When you open a jar and remove sauerkraut, always check that the remaining cabbage is still covered by brine. If the level has dropped, you can make a simple brine at home by dissolving 1 tablespoon of salt in 1 cup of water and pouring it over the cabbage until it is submerged again. This simple step can add weeks to the life of an opened jar.

How to store opened sauerkraut properly

Once you open a jar, the clock starts. To slow spoilage, store the jar in the coldest part of your refrigerator—usually the back of a shelf or the bottom drawer, where the temperature is most stable. Keep the lid on tightly between uses, and never leave the jar sitting on the counter or in a warm spot.

Always use a clean spoon or fork to remove sauerkraut from the jar. Dirty utensils introduce bacteria that will speed up spoilage. If you notice the brine is cloudy, has a film on top, or smells off, do not add more brine—discard the jar. Cloudiness can indicate bacterial growth, and a film (called kahm yeast) is harmless but signals the sauerkraut is near the end of its life.

Signs sauerkraut has spoiled

Sauerkraut that has gone bad will show clear warning signs. Look for visible mold—white, green, or black fuzzy growth on the surface or sides of the jar. Smell the jar before eating; spoiled sauerkraut will have a rotten or off smell, very different from its normal sour tang. If the cabbage feels slimy or mushy instead of crisp, or if the brine has turned cloudy and thick, the jar should be thrown away.

A thin white film on the surface (kahm yeast) is not mold and is not dangerous, but it means the sauerkraut is aging and should be used soon. If you see it, skim it off with a clean spoon and use the sauerkraut within a few days. If the cabbage underneath is still crisp and smells normal, it is safe to eat.

Homemade sauerkraut fermentation and storage

Homemade sauerkraut fermented in a jar at room temperature will develop a sour flavor over 1 to 4 weeks, depending on the temperature and your taste preference. Once it reaches the flavor you like, move the jar to the refrigerator. The cold temperature slows fermentation dramatically, so the sauerkraut will stay relatively stable for several months.

Even in the refrigerator, homemade sauerkraut will continue to ferment very slowly, which is why it can last longer than store-bought versions. However, once you start opening the jar regularly and removing portions, treat it like opened sauerkraut and use it within 1 to 2 months. The same rules apply: keep the cabbage submerged, use clean utensils, and store it in the coldest part of the refrigerator.

Freezing sauerkraut to extend storage

If you have more sauerkraut than you can use in 2 months, freezing is an option. Sauerkraut can be frozen for up to 8 to 12 months, though the texture will become softer after thawing because ice crystals break down the cell walls of the cabbage. The flavor remains good, so frozen sauerkraut works well in cooked dishes like stews, casseroles, or sausage and sauerkraut, where texture is less important.

To freeze sauerkraut, transfer it to a freezer-safe container or bag, leaving a little headspace because the brine will expand as it freezes. Label the container with the date. Thaw it in the refrigerator overnight before using, and do not refreeze once thawed. Frozen sauerkraut that has been thawed should be used within 3 to 5 days.

Storage location and temperature control

The best spot for sauerkraut is the coldest, most stable part of your refrigerator. Most refrigerators maintain 35 to 40°F, which is ideal for sauerkraut. The back of a shelf or the bottom drawer (if it is not the crisper drawer) tends to be colder than the door, where temperature fluctuates every time you open it. Avoid storing sauerkraut on the door shelves, where it will warm up repeatedly and spoil faster.

If your refrigerator runs warmer than 40°F, sauerkraut will not last as long. Check your refrigerator temperature with a simple thermometer to be sure. If it is running warm, adjust the thermostat or consider having it serviced. A refrigerator that is too warm will shorten the life of all your foods, not just sauerkraut.

Frequently Asked Questions

Can I eat sauerkraut if it's past the expiration date on the jar?

An expiration date is a manufacturer's estimate, not a hard deadline. If the jar is unopened, the seal is intact, and the sauerkraut looks and smells normal, it is usually safe to eat past the printed date. Once opened, the date becomes less relevant—use the 1 to 2 month guideline and trust your senses instead.

What does kahm yeast look like, and is it safe to eat?

Kahm yeast appears as a thin white or grayish film on the surface of sauerkraut, often with a slightly fuzzy texture. It is harmless and not mold, but it signals the sauerkraut is aging. Skim it off with a clean spoon and use the sauerkraut soon. If the cabbage underneath is still crisp and smells normal, it is safe to eat.

Can I store sauerkraut in a plastic container instead of glass?

Yes, plastic containers work fine for storage as long as they are food-safe and have a tight-fitting lid. Glass jars are preferred because they do not absorb odors and allow you to see the contents easily, but plastic is a practical alternative. Avoid storing sauerkraut in metal containers, which can react with the acidic brine.

How do I know if homemade sauerkraut is still fermenting in the refrigerator?

Active fermentation produces small bubbles that rise through the brine or collect at the top of the jar. If you see bubbles when you open the lid, fermentation is still happening. Once bubbles stop appearing and the sauerkraut tastes stable, fermentation has slowed significantly, and you should treat it as opened and use it within 1 to 2 months.

Is it normal for sauerkraut brine to get cloudy?

Slight cloudiness can happen as sauerkraut ages, especially in homemade versions, and is often harmless. However, if the brine becomes very thick and cloudy, or if it smells off, the jar should be discarded. Trust your nose—a normal sour smell is fine, but a rotten or unpleasant odor means it has spoiled.