How to ferment your food (and why you definitely should)
In the days before refrigerators, chemical preservatives, and fossil-fueled transportation, starving to death in the winter was a much more pervasive fear. Fermentation first arose more than 10,000 years ago, when the first known yogurt was (probably accidentally) created in North Africa, which paved the way for a crucial and healthy form of preservation that reshaped our relationship with food and survival.
Fermentation gives us a wide range of delicious concoctions, like sour pickles, funky kimchi, intoxicating alcohols, addictive cheeses, tasty breads, and so much more. As food preparation methods go, it’s one of the easiest ways to turn raw food into something spectacular — and have it keep for weeks or months.
Just because it’s easy doesn’t mean you shouldn’t be careful, though. Sometimes unwanted mold or bacteria can sneak into a ferment, though there are ways of mitigating the likelihood of that. And if something does go bad, it’s easy to spot.
While you can ferment all kinds of edibles, including fish, milk, pork, and grains, we’ll be focusing on the decidedly less complicated category of vegetables, which require fewer resources and are much more approachable for beginning home fermenters.
All you really need for many veggie ferments is the food you want to ferment, salt, and a vessel to put it all in. If you have that (or even if you don’t, yet), let’s dig into the weird world of fermentation and get pickling.
What is fermentation?
Fermentation is a biochemical process that happens when tiny, microbial bacteria break down rotting food. I know, it sounds unsettling, but by working with the ways foods naturally break down, we can preserve and transform all kinds of foods into culinary creations that are both beneficial to health and will last for a long time.
Using pickles as an example, let’s break down — get it? — exactly what happens when you ferment a vegetable like a cucumber.
What you’re trying to do is foster an environment where certain microbes that ferment foods can thrive. Bacteria and molds will consume sugars and starches in foods like cucumbers, and expel acids and alcohols. Since cucumbers are not starchy, the microbes mingling with this porous veggie will primarily create acid, giving pickles that signature sour bite. This is known as lacto-fermentation.
To make sure you’re only getting “good” bacteria and molds in your jar of fermenting cucumbers, you need to submerge the veggies in a salty brine. The “bad” bacteria that can make us sick doesn’t like salt, so won’t show up in a salty brine. Once your mix is stored in a cool area, you’ve created an adequate fermentation environment where good microbes will turn cucumbers into pickles. As an added bonus, when you consume these microbes, they assist the microbes already inside you and can boost your immune system along with amplifying the nutrition of some foods. Sauerkraut is known for being great for your gut and a good source of vitamin C.
Of course, not every fermentation is going to be perfect. Be sure to check your ferment frequently. If you see mold on top of it, it’s possible there isn’t enough salt in the brine, something poked out of the brine, and/or the temperature is a little too warm. You should throw that batch away, generally. There are some pretty harmless pale scums that can form on top of ferments that you can scoop out and not worry about, but that comes down to personal preference and comfort. Consult some guides with pictures (like this one) to determine if what you’re seeing is mold and if it compromises your operation.
Now that you know how it works, let’s jump into a simple example of a good place to start with fermentation: Cabbage.
How to make sauerkraut
Sauerkraut and kimchi, both commonly created by fermenting cabbage, are two titans of vegetable fermentation. This is because cabbage on its own isn’t very titillating, but it’s incredibly easy to ferment, and the end product is divine.
You can create a simple sauerkraut by slicing up green cabbage, massaging it with salt, and then stuffing it into a jar or crock so it can sit submerged in brine and ferment for a month or so.
There are a few things to note when it comes to selecting your cabbage, how you pack it, and where you store it. This will help you to better control the fermentation process and end up with the tastiest sauerkraut possible.
How to select your cabbage
When selecting cabbage, it’s best to shop directly from farms or farmers markets, which is where you’ll find the freshest, most local cabbage possible. The kind of cabbage you’re looking for is green. It’s best to shop in-season (around spring and fall). Cabbages grown in their preferred weather conditions are able to exploit the sun and the soil as much as possible, making them plump with nutrients, sugars, and moisture.
As mentioned, microbes feed on sugars and starches to survive, releasing lactic acid and alcohol as they digest. The more sugar a veggie has inside it, the more the microbes can digest, and thus, the more transformed the end product. So getting good, colorful cabbage will give you a better end result.
For sauerkraut, you’ll want an amount of salt weighing about 2 percent of the weight of the cabbage you’re using — a kitchen scale is really helpful here. (That works out to 1.5 to 2 teaspoons of salt for every pound of cabbage.)
With a nice salt massage, ideally gray sea salts or Himalayan pink salts that are mineral-rich salt with no additives, your cabbage will release a whole bunch of moisture, creating its own brine. That brine protects it from other harmful bacteria and molds.
You want enough brine that when you pack your sliced and massaged cabbage into a container, the liquid will completely cover the solids. If you have cabbage poking out of its brine, it can get attacked by harmful bacteria that float around in the air, just like regular food would if you left it out in the open. If the brine doesn’t cover it all, keep massaging and try adding a tiny bit more salt.
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Get a good container
Once your cabbage is packed into your container, such as a glass jar or a clay crock (see if any local potters make them!), it’s common to cover it with plastic wrap or something similar (an extra cabbage leaf works!) and place a weight on top of that to keep floating pieces of cabbage from popping out. On top of that, you’ll want to apply a lid, ideally one with a burper so that the gases that build up can safely escape without letting air in. If you don’t use a burper, you’ll need to open the container at least once a day or else the gasses could build up pressure and cause an explosion.
Find a dark area and wait
Now put it in a dark place at room temperature for anywhere from a couple weeks to a month plus. The longer you let it ferment, the softer and more sour it will be. It’s perfectly fine to taste it every few days, and once it’s to your liking, you can pop it in the fridge. The low temperatures will stop the ferment and preserve your creation for several months.
That’s sauerkraut! If you want to experiment with it, you can add all kinds of herbs and spices to your ferment, pop in some garlic, and add a little lemon juice or even some grated apple to enhance the flavor.
As for kimchi…
For kimchi, the process is similar, but you’ll want to use napa cabbage and add the all-important Korean chili pepper for that signature spice as well as other ingredients like garlic, ginger, and scallions. There’s not one single kimchi recipe, so search around for one you like and do some experimenting of your own.
Something fun about fermentation is how much allows for experimentation and improvisation when it comes to trying different vegetables or combining different flavors together.
After I got a couple ferments under my belt — one sauerkraut and one pickled red onion with lime, both very tasty and successful despite my worries — I was much more comfortable with the whole process and started to take my own spins on things.
In the fall I wanted to make a sauerkraut using fresh cabbage and some apples I had in the fridge. While at the farmers market, I saw some fluffy fennel, their deep green fronds reminding me of a lemon dill sauerkraut recipe I had seen before. All of a sudden my cabbage/apple sauerkraut had garlic, lemon juice, and fennel in it.
After a month fermenting in the cabinet, it’s absolutely delicious. The apple and lemon both add an extra bright bite; the fennel brings in both a bit of attractive green coloring and an herby undercurrent; and the garlic provides a kind of funky sweetness.
I’ve also done some variations on julienned and pickled carrots and daikon, which I use for an acidic crunch on homemade Vietnamese banh mi sandwiches and a delicious creation my wife came up with that combines sweet and spicy tofu with a scallion pancake wrap. I wanted to bring a little heat and extra flavor to the carrots and daikon, so in the first batch I added three Thai chili peppers. Their slightly earthy flavor melded beautifully with the other veggies, but ended a little spicier than I wanted. The next batch I used a couple of cherry peppers, a bit milder but a little sweeter than I was looking for. Next I might try a combination of different peppers.
For these more pickle-y ferments, the veggies themselves may not release enough moisture naturally to make their own brine (and you don’t want to squeeze it out of them), so you’ll need to add some water and possibly some sugar to help them get going. Search for specific recipes to find amounts, because they can vary quite a bit depending on what you’re pickling.
One time I tried to make a take on sambal, a spicy pepper paste, using jalapenos. At the end of the process, it seemed like no fermentation had happened at all. It mostly tasted like raw jalapenos and garlic, so I tossed it.
That will happen sometimes. The lesson I learned was that I need to make certain that I’m using enough salt and have enough sugar to get it going. Sometimes that comes down to experimenting, because it’s not really an exact science and not every vegetable is going to have an identical makeup.
Through success and failures you can learn a lot about fermentation. By pulling from a variety of resources, combining different ideas together, and just trying out ideas, you can come up with some really tasty creations.
You can experiment with fermentation on other food groups too. There are plenty of helpful guides, kits, and classes for all kinds of things from brewing your own kombucha to making your own cheese. And there are plenty of recipes online and books about fermentation. My personal fermentation bible is by Kirsten and Christopher Shockey, which contains tons of recipes for all kinds of vegetable fermentations, fermentation tips, and fun personal touches.
When things start to warm up a little in the spring, the next ferment I’d like to try is eggplant. From what I’ve read in Fermented Vegetables, fermented eggplant may not be the most attractive thing, but it can be downright delicious. Outside of vegetables, I’m planning on brewing some kombucha, a drink I’ve come to love and am keen on having on hand at all times.
So, let’s try some new things. Let’s get fermenting.