Once you open a can or jar of sauerkraut the sauerkraut does need to be kept refrigerated to prevent spoilage.
If you do not refrigerate your opened sauerkraut or homemade sauerkraut the sauerkraut can grow bad bacteria on and in it which can make you sick.
So make sure to refrigerate the sauerkraut when not using or serving or eat it.
When kept in the refrigerator the sauerkraut should last up to 6 months as long as it's kept refrigerated.
You can also freeze the sauerkraut but it kills off some of the good bacteria.
It's OK to freeze sauerkraut.
But when you freeze sauerkraut you kill off some of the good bacteria known as probiotics so you won't get all the health benefits from frozen sauerkraut as you would get with fresh sauerkraut.
But sauerkraut does freeze well and is still safe to eat after the sauerkraut has been frozen.
Frozen sauerkraut will last for up to a year and longer as long as it's kept frozen but it won't be as fresh and it's best to consume the sauerkraut within 6 months of freezing it.
The longer you leave the sauerkraut in the freezer the less fresh the sauerkraut becomes.
I prefer to just keep my sauerkraut in the refrigerator and eat it within a few months.
The fresher the sauerkraut the better tasting and more nutritious and healthy it is.