Sauerkraut: What Makes it Sour?

Enlarge Image Image Gallery A reuben sandwich just tastes better with a little sauerkraut in the mix. iStockphoto.com/Robyn Mackenzie

You can find sauerkraut almost everywhere in America. If you’re in a major city, you can probably buy a hot dog smothered in the stuff (though, before I get letters, no sauerkraut taints a Chicago dog). Many restaurants have a Reuben (a sandwich claimed by both Omaha, Nebraska, and New York City) on the menu, and, if neither of those appeals, just head to any German household for great bratwurst (or other pork product) and kraut. But how is sauerkraut made? Why do you make it in a crock? And just what makes it “sour,” anyway? 

Sauerkraut (German for “sour cabbage”) is part of a whole family of fermented foods that we enjoy (such as beer, yogurt, bread, wine and cheese). Though “fermented cabbage” may not have an appetizing sound, it has a storied history – enjoyed by the Romans, the Chinese who worked on the Great Wall, the Mongols and, of course, my German ancestors. Eventually, Dutch sailors discovered that serving it shipboard helped prevent scurvy (because of its vitamin C content). Sauerkraut packs a nutritious punch, containing vitamins C, B and K, riboflavin, iron and many others. Cabbage is more nutritious after it’s been fermented than when fresh. 

Creating sauerkraut requires only a couple of ingredients – cabbage and salt. Usually, you don’t even need to add water because the salt pulls liquid out of the cabbage. The beasties that do the fermenting, Lactobacillus species of bacteria, don’t have to be added to the mix because they’re already present on the cabbage (and pretty much everything else – especially things that grow close to the ground). Lactobacilli are very friendly for humans: L. acidopholus is involved in making yogurt, and L. sanfanciscensis makes sourdough bread sour. For sauerkraut, we’ll be making use of L. plantarum.