Sauerkraut must be kept refrigerated to retain its flavor and discourage the growth of bacteria. Refrigeration is especially necessary if the container of sauerkraut has been opened.
Sauerkraut recipes vary, but at the heart of all of them is fermented cabbage. Sauerkraut kept in the refrigerator remains edible for up to several months as long as it is covered tightly. It can also be frozen or canned to preserve it for longer periods of time. One method of preparation for canning sauerkraut involves boiling the sauerkraut and the brine with which to pickle it, and another only uses brining and not heat.