People have fermented foods for thousands of years. At first, ferments must have happened by sheer accident—a handful of vegetables forgotten in salty water or a misplaced bowl of porridge, discovered days later and showing signs of life and gentle bubbling. When those first curious cooks tasted these supposed mistakes, they would have immediately realized they were onto something tasty.
Some people are put off by the idea of fermentation because they worry it they will mess it up and get sick. Fermentation is actually extremely safe. In fact, it’s safer than many other types of food preparation. Bad bacteria—including botulinum—cannot survive the acidic environment of a fermentation. The good bacteria crowd them out and they die.
- Preserves food. Fermented cabbage (i.e., sauerkraut) keeps for months, whereas a head of cabbage rots after a week or two. In rendering cheese, fermentation increases the shelf-life of milk. Before the dawn of refrigerators, chemical preservatives and canning, people preserved their food by either fermenting, salting or drying it.
- Increases food’s nutritional value. Fermentation makes certain nutrients, such as B vitamins (thiamin, riboflavin, niacin) more bioavailable, and reduces toxins and anti-nutrients such as phytates found in grains. It makes food easier to digest. Raw fermentations contain live cultures, which improve your gut health and boost your immunity. I could go on and on about the health benefits. (For more info on the health benefits read the book The Good Gut.)
- Saves money. Store-bought fermented foods—crème fraîche, cucumber pickles, sauerkraut and so on—can cost a small fortune (but you do get what you pay for). Fermenting your own versions saves money. You can also ferment some foods that would ordinarily end up in the compost (or worse, landfill). I make pickled watermelon rinds and fruit scrap vinegar out of what most people consider trash.
- Reduces energy consumption. Most fermented foods require little energy to prepare, if any, and they can survive without refrigeration (although they will last longer in the fridge). As fossil fuels dwindle and we resort to more drastic measures to extract them from the earth (e.g., tar sands), we can look to clean energy cooking techniques like fermentation to conserve energy and help reduce our fossil-fuel dependence.
- Tastes delicious. Pickles. Chocolate. Coffee. Tea. Cheese. Yogurt. Ketchup. Sourdough. Kombucha. Vanilla extract. Wine. Beer. Mead. Soy sauce. Sauerkraut. Kimchi. Kefir. Buttermilk. Hot sauce. All the good stuff requires fermentation at some point in its preparation.
For the most part, I use jars with screw-top lids for fermenting vegetables. I also have bail-lid jars with rubber gaskets. I like this bail-lid style because the gasket enables built-up carbon dioxide—which may lead to exploding jars—to escape while keeping air out. Don’t worry if you don’t have jars like these! You can avoid explosions by burping—in other words opening—your jars daily. (By the way, I have never had a jar explode.)
You’ll also need a knife for chopping and a surface on which to chop, a bowl for mixing and possibly something for pounding the vegetables in order to bruise them. For sauerkraut, I simply squeeze the chopped cabbage with my hands. For hot peppers I would rather not do this with bare hands… I have found that the bottom of a small jar works well for this purpose.
I buy organic vegetables. I once tried to ferment ginger and it did not work. I read later in The Art of Fermentation by fermentation guru Sandor Katz (a.k.a. Sandorkraut) that conventional ginger may be irradiated, which kills its naturally occurring lactic acid bacteria. (Nothing conventional about irradiating our food, in my opinion.) These bacteria perform the fermentation. This would help explain why my ginger ferment showed absolutely no signs of life after many, many days. It was not likely organic.
If you want to treat yourself, I highly recommend buying a copy of Katz’ indispensable and beautiful book. It’s like my bible. Because I refer to it so often, I keep in next to my bed at night 😉
- 1 head of cabbage, approximately 2 pounds
- 2 teaspoons of salt or to taste
For krautchi, a cross between sauerkraut and kimchi, I also add:
- 5 or 6 small radishes or 1 medium-size daikon or watermelon radish
- lots of minced garlic (let’s say 8 cloves or so)
- a couple of inches of grated or minced ginger
- a bit of cayenne pepper (start with 1/4 teaspoon and add more if desired) or a minced jalapeño or serrano chili if in season
The basic method
Lactic acid bacteria (LAB), which occur naturally on all vegetables, increase after harvest. When you submerge vegetables under their juices or water, LAB perform the fermentation. Bad bacteria cannot survive the acidic environment of a LAB fermentation. The LAB thrive in the ferment and dominate it, crowding out the bad guys.
To make sauerkraut, follow Sandorkraut’s four basic steps:
Wash a head of cabbage, core it and set aside a couple of outer leaves. You will use these later. To prepare the cabbage for sauerkraut, cut the head into quarters and chop it. In order to ferment properly, vegetables must be submerged in water. Chopping increases the surface area of vegetables, which draws out their juice. The finer you chop, the more juice you’ll get and the easier time you’ll have submerging. If you want to add other vegetables and spices, prep those now as well. Good additions include carrots, shredded beets, chopped cauliflower and other “hard” vegetables. I find that vegetables like squash turn mushy and have a slimy texture.
Like chopping, salting draws out the vegetables’ juices. It also results in a crisper texture, slows down the fermentation (helpful if you have a very warm kitchen) and helps prevent mold growth. The hard-working LAB can tolerate salt, giving them an extra edge over salt-intolerant, unwanted microbes. Not to mention, salting the vegetables tastes good. I use a couple of teaspoons per head of cabbage. Use more or less to taste.
I usually dry salt, meaning I sprinkle the salt onto the vegetables, submerge them in their juices and then pour on additional water if necessary (this has rarely been necessary). I have used a brine—simply a mixture of salt and water—but prefer to eliminate this extra step for sauerkraut. You’ll make a brine to ferment whole vegetables however.
Toss the chopped vegetables in a bowl and sprinkle with a little salt. Repeat until you’ve chopped everything, tasting as you go. If you add too much salt, find more vegetables to chop and toss them in. Next, mix everything and grab the vegetables by the handful and squeeze. This squeezing breaks the cell walls and releases lots of water. (This is a great step for kids, by the way, and preparing and aging a batch of sauerkraut makes a great science lesson.) Set the bowl aside and wait a couple of hours for more juices to pool in the bowl.
N.B. If you want to add something spicy like diced jalapeños, add them after you have squeezed the vegetables. You’ll burn your hands if you squeeze hot peppers.
If you would like to add spices, sprinkle them into the bowl and mix. Classic spices for sauerkraut include caraway, dill, celery seeds, garlic and juniper berries. These add flavor and inhibit the growth of mold.
N.B. on the salt: Non-iodized sea salt contains many beneficial nutrients so I use that. Any salt with do though.
Getting the vegetables submerged is the most critical factor for success in vegetable fermentation. — Sandor Katz, The Art of Fermentation
By submerging the vegetables in water and cutting off their air and oxygen supply, you encourage the lactic acid bacteria to proliferate. (Remember, they ferment the cabbage.)
As you fill your jar, pack the vegetables tightly with your fist as shown in the pic above. This will force out air bubbles and submerge the vegetables beneath the liquid. If your jar lacks sufficient liquid to completely submerge the vegetables, you can weigh them down with something heavy in the jar and wait until more juice is released. Or you can pour a bit of water over the vegetables.
I haven’t had trouble with chlorinated water, but highly chlorinated water can kill the microbes. To prevent this, for water you may need, fill a vessel with it the day before you ferment and leave it open to the air to dissipate the chlorine.
Leave a couple of inches of space at the top of the jar. Once you have finished packing your jar, weigh the vegetables down with something. Sometimes a few cabbage leaves with suffice. Layer them over the chopped vegetables, or roll them up and stuff them into the jar. My favorite fix is a to place a jar within the jar. I use small glass yogurt jars for this. I put one on top of the cabbage leaves, then when I close the jar, the lid shoves the little jar down and the liquid rises up. Works like a charm. If you do something like this, you’ll probably need to leave a few inches of space at the top of your jar, depending on the size of your little jar.
Your ferment will become active within a couple of days. It maybe bubble up and ooze out of your jar, so be sure to place your jar on a dish of some sort.
Wait for the sauerkraut to ferment, but do not wait to burp your jars! When the fermentation is most vigorous in the first several days (depending on your kitchen), carbon dioxide will build up in the jar. Open your jar daily to release CO2 so your jar does not explode. I love the color of my sauerkraut, but not splattered on my walls and ceiling. While you have the jar open, if you see any floating vegetables, use a clean hand or utensil to shove the vegetables down and release any air. My marble pestle works well for this.
After two to three days (again, depending on your kitchen), the microbes will have already transformed your cabbage into a young sauerkraut. Taste it at this point. If you like the mild taste, move your jar to the refrigerator to retard the fermentation. I like my ferments strong and sour, so I let mine ferment on the kitchen counter for longer—a month or more. Taste yours weekly until it has reached the flavor you want.
If you ferment regularly, at some point you may run into mold growth on the surface of a ferment, although I have never seen this on sauerkraut, only on beverages such as kvass (but never on my kombucha, knock wood). When air comes into contact with the surface of a ferment, the oxygen encourages the growth of mold. Don’t panic! This is both common and normal. Just skim off the mold as best you can. White mold is harmless (according to Sandorkraut) but do not eat other colors. The longer the mold develops, the more entrenched it becomes. Get it out as soon as possible.
You may run into another problem of brown mush on top of the sauerkraut. This has happened to me a couple of times. If the kraut isn’t submerged properly, this can happen. Scrape off the top layer and compost it. The food underneath will be fine.
Your kraut is ready! Congratulations. Sandor says that the bacterial composition of ferments changes over time, with different types of lactic acid bacteria waxing and waning. He suggests eating the ferment over a long period to expose yourself to a wide variety of good bacteria.