Sauerkraut is produced by a process called ‘anaerobic’ fermentation, meaning ‘without oxygen’. It’s very simple to achieve in practice. You simply submerge the cabbage in a brine of its own juices and allow the naturally present bacteria to break down the sugars it contains. The process of ‘lacto-fermentation’ converts the sugars to lactic acid, making it tart. The combination of salt, anaerobic conditions, and acidity makes it very difficult for anything to survive besides the beneficial bacteria, so contamination is rare. If it does become contaminated, your nose will tell you as soon as you taste it.
Typical store-bought sauerkraut is far inferior to homemade. It's soggy and sulfurous. Raw homemade sauerkraut is crunchy, light, and tart.
My method is inexpensive and requires no special equipment. I've tested it many times and have never been disappointed.
- Wide-mouth quart canning jars (cheap at your local grocery store)
- Beer bottles with the labels removed, or small jars that fit inside the canning jars
- Three tablespoons of sea salt, pickling salt, or Kosher salt (not iodized table salt)
- Five pounds of green cabbage
- Chop cabbage thinly. Ideally the slices should be 2 mm or so wide, but it doesn’t matter very much. You can use a food processor, mandolin or knife.
- Put all the cabbage together in a large bowl and add the salt. If the salt is not very dense (sometimes finely ground sea salt can be fluffy), you can add up to 5 tablespoons total. Mix it around with your hands. Taste some. It should be good and salty.
- Let the salted cabbage sit in the bowl for 30 minutes or so. It should be starting to get juicy.
- Pack the cabbage tightly into the canning jars. Leave 2-3 inches at the top of the jar. When you push on the cabbage in the jar, you should be able to get the brine to rise above the cabbage. Try to get rid of air bubbles.
- Put water into the beer bottles and place them into the canning jars. The weight of the bottles will keep the cabbage under the brine. It’s okay that some of the brine is exposed to the air; the cabbage itself is protected.
- Let it sit for 2 weeks at room temperature! As the fermentation proceeds, bubbles will form and this will raise the level of the brine. This is normal. You might get some scum on top of the liquid; just check for this and scrape it off every few days. It won’t affect the final product. If the brine drops to the level of the cabbage, add salt water (1 tsp/cup, non-chlorinated water) to bring it back up.
- Taste it! It should be tart and slightly crunchy, with a fresh lactic acid flavor. If fully fermented, it will keep in the fridge for a long time.