The Basics

Sauerkraut is traditionally made by lactic acid fermentation. The cabbage is shredded and packed tightly with salt, which draws out the vegetable's juices. Naturally occurring yeasts consume the sugars in the juices and convert them to alcohol, and a complex ecosystem of beneficial bacteria convert that alcohol into lactic acid. Potentially harmful bacteria and molds can't live in the intense acidity of the sauerkraut's brine, so as long as the cabbage isn't exposed to the outside air, it can be held for a very long time. Commercial sauerkraut sometimes shortens this process by simply pickling the salted cabbage with vinegar, but that method produces an inferior product.

Cooking the Kraut

The salty, acidic brine should be rinsed from the sauerkraut once it's opened and before it's used. The raw kraut has a slightly crunchy texture and a mouth-puckering acidity that makes it an excellent garnish on a rich, fatty sausage, but a few bites is enough for most palates. However, if the sauerkraut is slow-cooked for an extended period in a suitable liquid, it changes dramatically. Its texture softens and its flavor mellows to a mild tang, making it an excellent complement to the flavors of cured and smoked meats. There are several appropriate cooking liquids, including plain water, but broths and alcohol are the most common choices.

Broth

A richly flavored broth can impart its own taste to the sauerkraut, and over time will combine with the kraut's flavors to form a harmonious end result. Beef broth isn't a good choice for sauerkraut, but chicken broth, vegetable broth and pork or ham broth all work well. Not much broth is required, because the kraut will lose volume as it cooks. For a quart of sauerkraut, a cup of broth is usually enough for two to three hours' simmering in a covered pot. Stir the kraut occasionally as it cooks, and add more broth if it seems to stick to the bottom.

Alcohol

Both wine and beer are also common cooking liquids for sauerkraut, and they're used in much the same way as broth. If you plan to cook your kraut in beer, choose a light beer or ale with minimal hops. Strongly hopped beers can become unpleasantly bitter after slow cooking, and dark beers give the kraut an unpleasant appearance. White wines are another excellent choice. Dry white wines help preserve the tartness of the kraut, but a slightly off-dry German or German-style white -- a Riesling, Rivaner, or Gewurtztraminer -- gives a rounder, mellower flavor. Like dark beers, red wines give the kraut an unattractive hue.

Other Ingredients

Of course, your choice of cooking liquids is only part of the equation. Most cooks add a number of other ingredients to flavor the sauerkraut, and be flavored in return. Onions and apples are often added to the pot, contributing sweet and savory notes and some moisture. Bay leaves, juniper berries, peppercorns and caraway seeds are also traditional choices in varying parts of Europe. Most importantly, smoked and cured meats such as pigs' feet, ham hocks, sausages and duck or goose confit are usually added during the cooking time. The meats add rich flavors to the sauerkraut, while the kraut flavors and tenderizes the meats.