Fermenting Foods—One of the Easiest and Most Creative Aspects of Making Food from Scratch
December 29, 2013
By Dr. Mercola
Ninety percent of the genetic material in your body is not yours but belongs to the bacteria that outnumber your cells 10 to 1. These bacteria have enormous influence on your digestion, detoxification and immune system.
Sandor Katz is a self-described “fermentation revivalist,” and has published two books on this topic, along with a third on the underground food movement. He’s a native of New York and a graduate of Brown University. Sandor currently lives in Tennessee, where he pursues his interest by presenting workshops around the world on fermentation.
Fermented food is something I too have become quite passionate about, and I firmly believe it’s an absolutely essential factor if you want to optimize your health and prevent disease. The culturing process produces beneficial microbes that are extremely important for human health as they help balance your intestinal flora, thereby boosting overall immunity.
Moreover, your gut literally serves as your second brain, and even produces more of the neurotransmitter serotonin—known to have a beneficial influence on your mood—than your brain does, so maintaining a healthy gut will benefit your mind as well as your body.
Fermented foods are also some of the best chelators and detox agents available, meaning they can help rid your body of a wide variety of toxins, including heavy metals.
“It wasn’t until I was in my 20s... that I first began to learn about and observe some of the digestive benefits of eating live culture fermented foods,” Sandor says.
“It was another decade after that when I left New York City, moved to rural Tennessee, and got involved in keeping a garden that I first had a reason to investigate the practice of fermentation. All of the cabbages were ready at the same time, and I thought I should learn how to make sauerkraut. I did a little bit of research in cookbooks and started making sauerkraut. Thus began my investigations into fermentation about 18 years ago.”
Starter Cultures versus Wild Ferment
When fermenting vegetables, you can either use a starter culture, or simply allow the natural enzymes in the vegetables do all the work. This is called “wild fermentation.” Personally, I prefer a starter culture as it provides a larger number of different species and the culture can be optimized with species that produce high levels of vitamin K2, which research is finding is likely every bit as important as vitamin D.
For this past year, we’ve been making two to three gallons of fermented vegetables every week in our Chicago office for the staff, which they can enjoy with the lunch we provide as an employee benefit.
We use a starter culture of the same probiotic strains that we sell as a supplement, which has been researched by our team to produce about 10 times the amount of vitamin K2 as any other starter culture... When we had the vegetables tested, we found that in a four- to six-ounce serving there were literally 10 trillion beneficial bacteria, or about 100 times the amount of bacteria in a bottle of high potency probiotics.
There are about 100 trillion bacteria in your gut, so a single serving can literally “reseed” 10 percent of the bacterial population of the average person’s gut! To me that’s extraordinary, and a profoundly powerful reason to consider adding fermented vegetables as a staple to your diet.
You don’t have to use a starter culture however. Wild fermentation is fermentation based on microorganisms that are naturally present in the food you’re fermenting. It’s just as simple as using a starter culture, but it will take a little longer for it to ferment.
“It’s very predictable when you salt and submerge vegetables [in their natural juices or brine]. The bacteria that will initiate at fermentation are always Leuconostoc mesenteroides. Then it’s a successive process whereby, as the pH changes and as the environment changes, different strains of bacteria come into dominance...” Sandor explains.
“Typically, in a mature sauerkraut, the late-stage bacterium that’s dominant is Lactobacillus plantarum. It’s a very predictable succession, what happens with raw vegetables, [but] the specific strains will always be somewhat different depending on the vegetables you’re using and the environment that you’re doing it in.”
To Salt or Not to Salt?
Whether or not to use salt also largely comes down to personal preference. While it’s not a necessity, Sandor does provide some compelling reasons for adding a small amount of natural, unprocessed salt—such as Himalayan salt—to your vegetables. For example, salt:
- Strengthens the ferment’s ability to eliminate any potential pathogenic bacteria present
- Adds to the flavor
- Acts as a natural preservative, which may be necessary if you’re making large batches that need to last for a larger portion of the year
- Slows the enzymatic digestion of the vegetables, leaving them crunchier
- Inhibits surface molds
Again, natural unrefined salts are ideal as they contain a broad spectrum of minerals, and the fermentation process makes the minerals more bioavailable—a win-win situation!
“Just now, I’m getting near the bottom of a 55-gallon barrel of sauerkraut that I made last November mostly out of radishes. That would not be possible without the addition of salt,” Sandor says. “You can make sauerkraut, and then you can ferment for several weeks in a cool environment. Maybe you could get to several months. But what would happen eventually to a salt-free kraut is that enzymes in the vegetable would basically digest the fiber of the vegetables. It would just turn into a mush, which is not at all appealing to me.”
What Type of Container Should You Use?
There’s no need to over-think or spend large amounts of money on containers. The material they’re made of is important however. You do NOT want to use plastic or metal. Plastics are loaded with chemicals you don’t want leaching into your food, such as bisphenol-A (BPA) and phthlalates. Metal is also inadvisable as salts can corrode the metal. Even if you don’t add salt, most vegetables have some natural salts in them. Good options include:
- Glass jars (wide-mouthed Mason jars are ideal, so that you can get your whole hand in there to press down the vegetables)
- Ceramic crocks
- Wooden barrels
I completely agree with Sandor’s sound general advice here:
“My main message that I would encourage your viewers and listeners to remember is you don’t need to buy anything special. You need a head of cabbage or a couple of pounds of vegetables, and beyond that everything you need is already in your kitchen. Whatever tools or devices you typically use to chop or shred vegetables, you can use that. Add some salt, mix it around, squeeze it with your hands for a couple of minutes, and stuff it into a jar.
Beyond that, you could use any kind of shredding device you like: a mandoline, a food processor, a continuous feed food processor, or a specialized cabbage-chopping device. You could buy beautiful elegantly designed crocks. But you have everything that you need to get started in your kitchen. Don’t let the beautiful crock that you don’t have yet be the reason why you don’t start doing this.
I think it’s really important to recognize that you don’t need anything special to start a fermentation practice. You might decide you want to play with starter cultures, but you don’t need starter cultures to get started. You might decide that you want to invest in a crock, but you don’t need a crock to get started.
If you take two pounds of vegetables, you can stuff a quart-sized jar with those. Just chop them up. Shred them. They can be extremely fine, or they can be coarse and chunky. It doesn’t matter. Lightly salt them to taste or else weigh them and measure out 1.5 percent salt. I prefer to salt them lightly to taste.”
Two Helpful Tips...
As Sandor explains, an important step in the process is to squeeze the vegetables before packing them into the jar. You don’t need any fancy tools for this; just use your hands. “Bruising” the vegetables in this way allows the cell walls to break down and release their juices. Capture the juice in the jar you’re going to ferment your vegetables in. Then stuff as many veggies into the jar that will fit. You want to stuff them in as tightly as possible, forcing out any air pockets that might ruin the batch. The brine should cover the vegetables.
Sandor then simply covers the jar with the lid and leaves it on the kitchen counter. A helpful tip I learned from Caroline Barringer is to top off the jar with a cabbage leaf, tucking it down the sides. Again, make sure the veggies are completely covered with the natural brine you squeezed out of the vegetables (or add a small amount of celery juice), and that the juice is all the way to the top of the jar to eliminate trapped air.
To speed up the fermentation, store the jars in a warm, slightly moist place for 24 to 96 hours, depending on the food being cultured. Ideal temperature range is 68-75 degrees Fahrenheit; 85 degrees max. You don’t want it too hot, as heat will kill the beneficial microbes. Don’t tuck them away in a dark closet and forget about them, though! As Sandor explains:
“The reason why you don’t want to just put it in the closet and forget about it is that it’s going to produce pressures, especially in the first couple of days. You want to relieve that pressure by opening the jar for a second. In that way, you don’t get a huge accumulation of pressure and risk the possibility of the jar exploding – or what’s more likely to happen, if you’re using a canning jar, where the glass is thick and the lid is thin, it will just contort the top. But it’s best to consciously release the pressure.”
The second tip is to smell and taste your ferment regularly. There’s really no objective moment when the fermentation is ready, so go ahead and taste it at frequent intervals, starting after about 48 hours. Then keep on tasting it every few days or a couple of times a week as it matures. It typically takes about a week for the optimal amount of fermentation to occur. Resist the temptation to eat out of the jar, however, as this can introduce undesirable organisms from your mouth into the jar. Instead, always use a clean spoon to take out what you're going to eat, then, making sure the remaining veggies are covered with the brine solution, recap the jar.
When the flavor is to your personal liking, transfer the jars into the refrigerator to dramatically slow the progression of the fermentation. Keep in mind, the vegetables will tend to get increasingly sour as time goes on, but according to Sandor, you could let the vegetables ferment for weeks and even months without worrying about them spoiling—after all, that’s what the fermentation process does: It preserves food without refrigeration.
Some additional info on how to ferment vegetables can be found here.
On Allowing Your Creative Juices to Flow
There is no food that cannot be fermented. As Katz states in a recent NPR article1, bread, coffee, pickles, beer, cheese, yogurt and soy sauce are all examples of foods that have been fermented at some point during their production process. That said, not every vegetable will produce equally delicious results, and not every food is as easily fermented as vegetables, but your imagination is really the only limit when it comes to what you can concoct.
“If you ferment summer squash, which are very watery, they will tend to get soft and mushy much faster than any other kind of vegetable would,” Sandor says. .. You can certainly ferment kale and other dark green vegetables, but the high levels of chlorophyll in these vegetables produce a really strong flavor in fermentation. I prefer to use dark green vegetables as a minor ingredient rather than as the primary ingredient. Then I feel like that strong flavor can become a nice accent.
But if it’s pure dark green vegetables, that flavor’s a little bit too strong for me, although I have heard from other people who really, really love it. In a way you can only learn what you like by experimenting.
My biggest batch every year has been from radishes. I have a farmer friend who uses daikon radishes as a cover crop over acres and acres of his land. He invites me to pick a truckload full of daikon radishes. And I augment that with some cabbages, some chili peppers and garlic, and make a 55-gallon barrel full every year... Then you can also ferment whole vegetables. The difference with whole vegetables is that you can’t pull the water out of them, so you need to mix up a brine – salty water – and ferment them in the salty water.
... I met a woman whose grandmother was from a town in Poland, where they used mashed potatoes in their sauerkraut. And I love making mashed potatoes sauerkrauts. What I do is I steam potatoes, I mash them up, cool them to body temperature, and then I layer the mash potatoes in with my salted cabbage. That makes a beautiful sauerkraut. You can really be experimental and go wild. You can add things other than vegetables.
... In German tradition, juniper berries are often used. I’ve been tasting wildly experimental krauts with curry seasonings and things like that. Really, the only limitation is our imagination, once we understand the underlying principles of getting the vegetables submerged.”
A Word of Caution Regarding Meat Fermentation
As just mentioned, while virtually any food can be fermented, and the fermentation process automatically renders the food exceptionally safe since the probiotics produced kill any pathogens present, a disclaimer regarding fermenting meats is worth taking note of.
“Fermenting vegetables is an intrinsically safe practice. In the United States, according to the USDA, there’s never been a single case of food poisoning reported from fermented vegetables. There is no danger. The food itself is a strategy for protection. Fermented vegetables are safer than raw vegetables,” Sandor says. “With meat, I can’t say this. The word “botulism,” which is the most feared food poisoning form of all, comes from the Latin word “botulist” or sausage. Until the advent of canning, which was in the 19th century, it was from fermented sausages that people knew about the rare food poisoning disease of botulism.
There’s a little bit more of a learning curve. Another limitation with fermentation of meat for preservation process is the acids, which are what enable certain fermented foods to preserve so well. Acids are produced from carbohydrates, and meat fundamentally lacks carbohydrates. There’s a tiny bit of glycogen, but not enough to support a significant fermentation and formation of lactic acid. Typically, when salami is produced, the meat and the fat are minced or ground. And then they’re mixed with a tiny bit of sugar. The sugar is really what is fermented by the lactic acid bacteria and creates the acidic environment that is able to preserve the meat.
It’s not through acidification alone that the meat is preserved. It’s a combination of acidification, drying (the meat is partially dried), and salting (the meat is always salted). Any one of these mediums could preserve the meat, either making it very, very dry as in something like jerky, making it very, very salty as in a food like prosciutto, or very highly acidic.”
To learn more, pick up one of Sandor’s books, The Art of Fermentation: An In-Depth Exploration of Essential Concepts and Processes from Around the World, or Wild Fermentation: The Flavor, Nutrition, and Craft of Live-Culture Foods.
You can also find more information on his website at WildFermentation.com.