How to Ferment Cabbage

Selecting the vessel to hold your cabbage during the fermentation process is the first hurdle you need to jump to create properly fermented cabbage. If you're just making small batches, all you need is a Mason jar or two. If you plan to make a larger batch, you may want to invest in a fermentation crock.

The key is to foster an oxygen-free or anaerobic environment that encourages the growth of lactic-acid producing bacteria. With exposure to oxygen, your fermenting cabbage can be contaminated with harmful bacteria or stray yeasts and microbes. While you can buy crocks and vessels specifically for making sauerkraut or fermenting foods, you can also use a simple Mason jar, as long as you follow one of these tips for maintaining an oxygen-free jar:

• Add a thin layer of olive or coconut oil to the top of the fermenting cabbage.
  
• Close the jar with a plastic or metal lid outfitted with an airlock -- a handy device available at most hardware stores.
• Top it off with a white lid and use a fermenting weight to help keep the cabbage submerged in the brine.

After you rinse the cabbage and remove the core, you have several option for preparing the cabbage for fermentation. Grating the cabbage by hand or in a food processor provides optimal surface area for the fermentation liquid to penetrate. Alternatively, you can slice it into thin ribbons or chop it into the size you desire, although larger pieces generally require a longer fermentation. Most sauerkraut and kimchi recipes call for shredded or thinly sliced cabbage.

Add the cabbage to a large bowl and toss it with unrefined sea salt. For one medium-sized head of cabbage, use approximately 1 tablespoon of salt. Knead the cabbage and salt together with your hands to start breaking the cellular structure down. Once it starts releasing liquid and transforms from crisp to limp, add it -- along with the liquid it releases -- to your Mason jars or crocks. Pack it in the vessel tightly, using a kraut pounder or the handle of a wooden spoon to press it down and get rid of as much air bubbles as possible.

Add the cover or lid to the fermentation vessel and place it in an out-of-the-way spot where it can sit undisturbed at room temperature -- keep the jar at temperatures ranging from 65 to 72 degrees Fahrenheit. Allow the bacteria at least four weeks of fermentation, but plan to leave it here for anywhere from one to six months. Test the cabbage every three to five days after the first month until it reaches the flavor you prefer. At this point, transfer the fermented cabbage to the refrigerator to store it for up to one year.

After 24 hours, the cabbage should be submerged in its own liquid. If it's not, The Kitchn recommends dissolving 1 teaspoon of sea salt in 1 cup of filtered water and adding enough of the solution to completely cover the cabbage.

You can add ingredients to complement your fermented cabbage according to your tastes and the type of fermented dish you're making. For example, add 1 tablespoon of caraway seeds to ferment along with each head of cabbage when you're making sauerkraut. If you're going for more of a kimchi-type flavor, add 1 tablespoon of garlic, 1 teaspoon of ginger, 1 teaspoon of sugar, 8 ounces of daikon radish, 4 scallions cut into 1-inch pieces and 1 to 5 tablespoons of red pepper flakes.

Signs that your fermentation has gone wrong and you need to scrap your batch to start over include the following signs of unsafe cabbage:

• Slime
• Mold
• Browned or pink cabbage
• Creamy-looking film
• Odor of yeast