[Kapusta Kwaszona (Poland); Kvashenoyi Kapusty (Ukraine); Sauerkraut (German, English); Chocrute (French); Liberty Cabbage (North America during World War I) Victory Cabbage (North America during World War II)]
Sauerkraut is cabbage that is salted to a precise degree and allowed to ferment, pressed under its own brine, through several generations of bacteria until it reaches a desired degree of sourness from a final lactic acid fermentation. It is then refrigerated or canned to stop further fermentation. It is usually shredded before fermentation, but In some cases it is made with lengthwise wedges of cabbage rather than shredded.
It is very important to the cuisines of Germany, Poland and Hungary, and also in parts of France with German exposure. Sauerkraut consumption has been declining in North America, which is not surprisingly since what is generally served here is of indifferent quality and prepared with little care.
More on Pickled and Preserved
History: Sauerkraut is said to have been first developed China by pickling cabbage in rice vinegar. It is said to have been a major supply for the building of the Great Wall of China to keep the workers from dying at a non-renewable rate. It was not salt fermented like modern sauerkraut, because salt was far to expensive to waste on laborers being worked to death, and it was made from Napa type cabbage (actually a turnip green).
From China it said to have been adopted by Mongols and Tatars who found it a durable food for their invading armies. They in turn carried it to Europe where it was adopted in Hungary, and by the 16th century was well known in Germany and Poland. I suspect that sauerkraut as we know it today was developed in Poland, where there have been huge salt mines since ancient times.
Kimchi is a Korean salt pickle similar to sauerkraut and most often made from Napa cabbage but also other vegetables, often with plenty of spicy chili flake (not all kimchi contains cabbage - or chili). Pao cai and Suan cai are Chinese sauerkrauts made from Napa cabbage in the north and from mustard greens in the south.
In Captain Cook's day (late 1700s), British ships carried barrels of sauerkraut to ward off scurvy (a vitamin C deficiency). The British later switched to limes but German and Dutch ships continued with sauerkraut. French and Spanish ships used potatoes for this purpose.
Buying & Storing: Sauerkraut is available fresh in the refrigerated section of many supermarkets, either in bags or jars. It will be on the shelves in metal cans or, more commonly for better brands, in glass jars. The two forms are interchangeable in most recipes but the fresh is higher in vitamin C and digestive enzymes. Fresh sauerkraut will keep refrigerated for 3 months or so. In the jar it should be used within a year because it slowly darkens to an unappetizing color.
Various Polish brands are now widely stocked by specialty and ethnic markets in North America (the photo specimen in Polish Vitarol brand, my favorite because it's packed with plenty of brine). These are put up in glass jars and most are pretty good. American brand Claussen's (refrigerated) is excellent though I consider it unaffordably costly, and the German brand Gundelsheim Barrel is highly thought of, but I've never seen it. Just because sauerkraut is in a bag rather than a jar doesn't mean it's better. Back in 2001 Trader Joe's sauerkraut in the bag was really awful, my opinion, shared by the Los Angeles Times test kitchen. Libby's Crispy Kraut is considered quite good at the economy end. Franks Quality Kraut (in cans) is considered among the best American made brands, but is somewhat regional in availability. In years past I used many jars of Meeter's Wisconsin Kraut, but Stokeley has discontinued that product. Of course you don't have to buy sauerkraut, it's not hard to make in 5 and 10 pound batches.
Prep & Cooking: Sauerkraut, either fresh or from a jar, does not need to be cooked and is often eaten that way. It is more often cooked, generally in a simple way. Cooking time depends on whether a soft or crispy result is desired. For a basic recipe with variations see Sauerkraut with Apples & Wine.
Health & Nutrition: Preventing scurvy is only one of sauerkraut's many medicinal properties. Current research shows it to be a powerful immune booster and cancer fighter, particularly for breast cancer. It was used during the American Civil War to drastically reduce deaths from smallpox among prisoners of war, and it has recently been found effective against avian flu in birds. It is also reputed to be a strong aid to digestion, even to relieve lactose intolerance.
Sauerkraut is high in fiber and has plenty of vitamins but is very low in calories, factors that have endeared it to a number of top models and other celebrities. They can eat plenty of it without gaining a pound. No need to jam their fingers down their throats after pigging out.