One of the means to preserve cabbage effectively is by making it into sauerkraut. It’s essentially cabbage fermented by its own lactobacillus, which is a kind of “good bacteria” that is present in all vegetables and fruits, guaranteeing a shelf life of months in cellars and fridges. It also has copious amounts of vitamin C, vitamin B6, copper, iron, and sodium, which your body can absorb easily due to the probiotics it contains. As much as you like sauerkraut, you may have prepare too much sauerkraut and start thinking about these questions. Does sauerkraut go bad? Can you freeze sauerkraut? How long does sauerkraut last in the fridge?
You can freeze sauerkraut, although it’s not recommended when you have opened the mason jar too many times, because bad bacteria will eventually get into the cabbage.
Some people are under the impression that already fermented food can’t go bad, but the reality is that sauerkraut can get contaminated, which is why it’s important not to leave a jar of sauerkraut open for too long.
If you’ve just your homemade sauerkraut and you feel that you made too much, prepare portions for freezing right away. Same if you bought it from the supermarket and you realized that what you bought might not be consumed in a relatively short timeframe.
Transfer the contents of the jar into an airtight freezer bag or container, making sure that no air is left inside, to prevent freezer burn. If possible, pour single-serving portions into various bags or containers to avoid having to thaw the whole pack of sauerkraut only to use a fraction.
Be mindful that the liquid it contains may expand upon freezing, meaning that you should leave a space of approximately 1 inch between the content and lid. That way, you’ll not risk the container’s seal being compromised nor would you leave enough air inside to damage the food.
There are mixed opinions on this. Some say it doesn’t, but others claim that the liquid will affect the texture upon expanding. In summary, it depends on how the sauerkraut is made and how much liquid is stored. What’s certain is that there will be a difference, but it might not be discernible in some cases.
The temperature shifts between thawing and refreezing harm food in general, and especially vegetables. I advise against refreezing sauerkraut in general, but if you absolutely need to, just make sure the sauerkraut has not been left out at room temperature for longer than 2 hours or that the seal has not been opened.
If you bought refrigerated sauerkraut, it should be able to retain its freshness for about 4 to 6 months once opened, at a temperature of 40º F or below. Initially, if you don’t open the jar too often, it should not spoil even after that time, though you should check it periodically for any awkward signs.
In the freezer, sauerkraut will probably last the same amount of time in optimal conditions, though there is an infinitely lesser risk of spoilage since the bacteria (both good and bad) is inhibited at temperatures below 0º F.
You can defrost sauerkraut in the usual ways you thaw most foods. It’s safer in the fridge, as bacterial activity is slower in that environment, and it can be left resting there for 3 or 5 more days. You can also try to submerge the unopened container in cold water, making sure that it doesn’t leak into the content. Finally pouring into a microwave-friendly bowl and using the microwave’s “defrost” function can help thaw faster, though you should use the sauerkraut immediately after.
Some people claim you can thaw it on the countertop at room temperature. Personally, I’d avoid doing that, although admittedly there is less risk of catching bacteria if you leave it there properly sealed. If you opt for this technique, remember to use the sauerkraut as soon as it’s completely thawed.
If you plan on including sauerkraut in your cooked dish, in most circumstances there is absolutely no need to defrost it. Just withdraw the pack of frozen sauerkraut from the freezer and pour the contents into the recipe while cooking. Easy-peasy! Just remember that cooking times might be longer if you add it in its frozen state, for that will affect the temperature of the whole meal.