Although sauerkrautGerman for "sour cabbage"is thought of as a German invention, Chinese laborers building the Great Wall of China over 2,000 years ago ate it as standard fare. Chinese sauerkraut, made from shredded cabbage fermented in rice wine, eventually found its way to Europe, where the Germans and Alsatians adopted it as a favorite. Today's sauerkraut is made by combining shredded cabbage, salt and sometimes spices, and allowing the mixture to ferment. It can be purchased in jars and cans in supermarkets. Fresh sauerkraut is sold in delicatessens and in plastic bags in a supermarket's refrigerated section. It should be rinsed before being used in casseroles, as a side dish and even on sandwiches like the famous reuben sandwich. Sauerkraut is an excellent source of vitamin C as well as of some of the B vitamins.