How Long Sauerkraut Stays Fresh in Your Refrigerator

Unopened Sauerkraut Lasts 4 to 6 Months, Opened Jars Last 1 to 2 Months

An unopened jar of sauerkraut will keep in your refrigerator for 4 to 6 months, sometimes longer. Once you open it, the timeline shrinks to 1 to 2 months. The difference comes down to what happens when air reaches the fermented cabbage—the brine (the salty liquid that preserves it) becomes less effective at protecting the food from spoilage organisms.

The exact length depends on how the sauerkraut was made and stored before you bought it. Commercial sauerkraut that has been pasteurized (heat-treated to kill bacteria) will last longer than raw, unpasteurized versions. Check the label or the store shelf to see which type you have. Raw sauerkraut, which still contains live beneficial bacteria, tends to have a shorter window once opened because those bacteria continue to age the product.

Temperature matters too. Keep your refrigerator at 40°F (4°C) or below. Warmer temperatures speed up spoilage, even in the sealed brine. If your fridge runs warmer than that, your sauerkraut will not last as long.

Key Takeaways

• Unopened sauerkraut in the refrigerator stays good for 4 to 6 months; opened jars last 1 to 2 months.
• Pasteurized sauerkraut lasts longer than raw sauerkraut because the heat treatment stops fermentation and bacterial activity.
• Once you open a jar, keep the cabbage submerged in its brine to slow spoilage and prevent mold growth on exposed pieces.
• Discard sauerkraut if it smells rotten (not just sour), shows pink or white mold, or feels slimy.
• A refrigerator kept at 40°F or below extends shelf life; warmer temperatures shorten it significantly.

Why Brine Is the Key to Keeping Sauerkraut Fresh

The brine—the salty liquid in the jar—is what keeps sauerkraut from spoiling. Salt creates an environment where harmful bacteria cannot grow, while the acidity from fermentation adds another layer of protection. When the jar is sealed and unopened, this brine stays stable and does its job for months.

Once you open the jar and start removing sauerkraut, you expose the remaining cabbage to air. Oxygen allows unwanted mold and bacteria to take hold, especially on pieces that float above the brine line. This is why keeping the cabbage submerged is critical. If you notice pieces sticking up above the liquid, press them down gently or add a little extra salt water (1 tablespoon salt dissolved in 1 cup water) to cover them.

If your opened jar sits in the fridge for weeks and the brine looks cloudy or develops a film on top, that is usually harmless yeast—a sign the fermentation is still active. You can skim it off. But if the brine itself smells rotten (not just sour or vinegary), the sauerkraut has gone bad and should be thrown out.

Signs Your Sauerkraut Has Spoiled

Sauerkraut should smell sour and tangy. That is normal and expected. Spoilage smells different—rotten, musty, or off in a way that makes you hesitate. Trust that instinct. If you are unsure, throw it out rather than risk foodborne illness.

Look for visible mold, which appears as pink, white, or fuzzy patches on the surface or on individual pieces. A small amount of white film (yeast) on top of the brine can be skimmed away, but any mold growing on the cabbage itself means the jar should be discarded. Also check the texture: sauerkraut should be crisp or slightly soft, not slimy. Sliminess indicates bacterial breakdown and means it is no longer safe to eat.

If the jar is still sealed and unopened but bulges outward, do not open it. Bulging means gas has built up inside, a sign of bacterial growth. Set it aside and throw it away.

How to Store Opened Sauerkraut Properly

After you open a jar, the goal is to minimize air exposure and keep the cabbage under brine. Store the jar in the coldest part of your refrigerator—usually the back of a shelf, away from the door. The door is the warmest spot because it opens and closes constantly, letting warm air in each time.

If you transfer sauerkraut to a smaller container to save space, use a glass jar or food-safe plastic container with a tight-fitting lid. Leave as little air space as possible at the top. Some people use a smaller jar that fits inside the original one, filled with brine, to keep the cabbage pressed down and away from air.

Do not use a fork or your fingers to grab sauerkraut directly from the jar. Always use a clean spoon or tongs. Introducing bacteria from your hands or utensils speeds up spoilage. Wipe the rim of the jar clean before closing the lid so no dried brine or cabbage pieces sit on the seal where mold could grow.

Homemade Sauerkraut Has a Different Timeline

If you ferment sauerkraut at home, the shelf life works differently. During fermentation (which takes 3 days to several weeks at room temperature), the cabbage is developing flavor and beneficial bacteria. Once fermentation reaches the taste you want, move the jar to the refrigerator. The cold slows fermentation dramatically but does not stop it entirely.

Homemade sauerkraut in the refrigerator will keep for several months, sometimes up to a year, because it is still in its original brine and has not been opened repeatedly. However, the flavor will continue to develop and become more sour over time. Some people prefer it that way; others find it too intense after a few months. Taste it periodically and decide when it reaches the flavor you like best.

Once you start opening a jar of homemade sauerkraut, apply the same rules as store-bought: keep it submerged in brine, store it in the coldest part of the fridge, and use clean utensils. Homemade versions are usually unpasteurized, so they may spoil slightly faster than commercial pasteurized versions once opened.

Extending Shelf Life Without Freezing

If you have an opened jar and want it to last longer, you can slow spoilage by keeping your refrigerator as cold as possible—ideally between 35°F and 40°F (1.5°C to 4°C). Check your fridge temperature with a simple thermometer. If it is running warmer, adjust the dial and wait 24 hours for the temperature to stabilize.

You can also transfer sauerkraut to a smaller jar as you use it, reducing the air space above the brine. Each time you remove sauerkraut, you are introducing a little oxygen; a smaller jar means less oxygen overall. Some people freeze sauerkraut in ice cube trays or small containers for long-term storage, though freezing changes the texture—it becomes softer when thawed. Frozen sauerkraut works well in cooked dishes like soups or stews but not as a crisp topping or side dish.

Frequently Asked Questions

Can I eat sauerkraut straight from the jar if it has been in the fridge for 3 months?

If the jar has been unopened and stored at 40°F or below, yes. Check that it smells sour (not rotten), has no visible mold, and the brine is clear. If it has been opened and sitting for 3 months, it depends on how well it was stored—if the cabbage stayed submerged and the jar was sealed tightly between uses, it is likely still safe, but taste a small piece first to check for off flavors.

What does it mean if my sauerkraut tastes fizzy or has bubbles?

Bubbles and a fizzy taste mean fermentation is still happening, especially in unpasteurized sauerkraut. This is normal and safe. The carbonation comes from beneficial bacteria producing gas. If you prefer less fizz, open the jar to release some gas, then reseal it and refrigerate.

Is the white film on top of my sauerkraut mold or yeast?

It is usually yeast, which is harmless. Skim it off with a clean spoon. True mold is fuzzy, colored (pink, orange, or dark), and grows on the cabbage itself. Yeast is a thin, smooth film on the brine surface. If you are unsure, discard the jar to be safe.

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

Yes, as long as the container is food-safe plastic and has a tight-fitting lid. Glass is preferable because you can see inside easily and it does not absorb odors, but clean plastic works fine for short-term storage of opened sauerkraut.

Does sauerkraut go bad faster if I keep it in the door of my fridge?

Yes. The door is the warmest part of the refrigerator because it opens and closes constantly. Store sauerkraut on a shelf toward the back of the fridge, where the temperature stays more stable and cold.