Sauerkraut is German word which literally means "sour cabbage". It is finely cut cabbage that has been fermented by various lactic acid bacteria. It has a long shelf life and a distinctive sour flavor, both of which result from the lactic acid that forms when the bacteria ferment the sugars in the cabbage. Sauerkraut is also used as a condiment upon various foods, such as meat dishes and in this case the Hot Doug's Chicago-style hot dogs.