Buying pre-packaged sauerkraut, choose the package where there is a pickle - firstly, it is very useful in itself, and secondly, in cabbage, which turns out to be without brine, vitamin C is quickly destroyed.
And, finally, buying - try it! The best sauerkraut - not salty, but slightly sour, ripening - without "presnynka", refreshing, crunchy and not soft.