Ferments: What are they, why are the important and how do we eat them?

When I entered graduate school, I had a vision of helping people heal using natural, whole foods. Over the past decade while practicing nutrition, I’ve learned that sometimes supplements are necessary, yet we cannot overlook the benefits of certain healing foods. Michael Pollen attempted to simplify human consumption for wellbeing: “Eat food, not too much, mostly plants.” I agree, and would clarify further from a nutritionist, locavore and Earth-mama perspective: “Eat whole, uncontaminated foods raised close to home – and ferments.”

Ferments. Not something I was familiar with as a child. We ate my mom’s Idahome wild meat-and-potato meals mixed with my dad’s Italian food faves. I don’t remember the first time I’d heard about fermented foods, though we ate yogurt regularly. I remember kraut on brats when I attended Oktoberfest in Munich in my twenties. I was wary of fermented veggies while traveling in Southeast Asia, lest they contained shrimp or shrimp paste (to which I am allergic).

Now, fermented foods are well established “functional foods,” thanks to their pivotal role in diversifying the microbiome and the many benefits of a thriving, internal ecosystem. In our modern world, we are not attuned to what feels good. Since we don’t need to prepare anything (thanks to convenience) or preserve ripe foods (thanks to refrigeration) and we’ve lost connection to cultural food traditions (thanks to industrialization) we rely on scientific studies to tell us what to eat.  

Fermented foods date back to the beginning of human existence because it offered almost every human population a way to preserve foods (1, 2). More than 5,000 fermented foods and beverages have been identified, though likely there are more because different regions modify recipes slightly based on what’s available (3). Ferments – yogurt, kefir and cheeses; tempeh, miso and natto; sauerkraut, kimchi and escabeche: sourdough, injera and dosa; beer, wine and kvass; drinking vinegars and sake; fermented fish and meats – have been staples in cultures around the world. And, now we know, they are essential to human health. Remember last week when I wrote about how humans evolved from bacteria? Is it possible that human health has evolved from consuming fermented foods?

What is fermentation, exactly? It’s the process of bacteria and/or yeasts feeding on sugars or proteins, thereby changing the flavor profile of a food, making the food more digestible for most people (2) and changing the health benefits of the food (like making antibiotics to fight pathogens) (3). Some foods ferment naturally, while others require yeasts or bacteria. Some fermented foods – cacoa and vinegar – require a combination of processes. Some variations between how foods ferment includes the presence or absence of sugars, proteins, oxygen, yeasts, bacteria and acidity. There are five main ways that food can be fermented: lactic acid, alcohol or ethanol, acetic acid, mold or alkali. For us science and alchemy foodies, I’ll try to clarify.

Lactic acid fermentation occurs naturally when bacteria feeds on the sugars in the absence of oxygen (“anaerobic”), thereby changing the pH to become more acidic; inhibiting the growth of other, competing organisms; reducing the potential for spoilage and preventing the development of toxins (4). Lactic acid fermentation is common with dairy, grains fruits and vegetables, producing yogurt, cheese, sourdough, kimchi and sauerkraut (5). Some of these foods, like yogurt, kefir, cottage cheese and fermented milk, also contain added bacterial Lactobacillus and Bifidobacterium strains. Lactic acid ferments have a mild, tangy and smooth flavor profile.

Alcohol fermentation occurs when yeasts are added and produces ethanol and carbon dioxide as biproducts (5). Examples include grapes fermenting into wine; barley fermenting into beer; honey into mead; rice into sake; apples into cider. Vinegars start as alcoholic fermentation, though they require a second, aerobic step.  

Acetic acid fermentation requires certain bacterial species, like Acetobacter, to convert alcohol to acetic acid when there is ample oxygen (“aerobic”) (5). This is the next step in the making of vinegars, such as apple cider, malt, rice and balsamic vinegars. This is also how water kefir and kombucha are made, as well as a specific Belgian beer called lambic (6). These foods are more pungent, due to their acidity.

Mold fermentation uses strains of fungi, such as Aspergillus and Penicillium strains, to feed off carbohydrates and proteins in foods (2). For example, mold fermented soybeans produce tempeh, miso or soy sauce. Many cheeses, like Brie, Camembert and blue cheeses use molds to “ripen.” 

Finally, alkali fermentation requires higher protein foods, like fish, meat, eggs and seeds, and require Bacillus bacterial strains (5). Many of these foods are more well known in their region around the world, rather than more globalized. Natto is a Japanese fermented soybean and pidan are preserved eggs. Some fermented fish condiments also are made via alkali fermentation.

For the rest of us who don’t want to know the nuances in fermentation processes, the key takeaway is that all natural foods can ferment and we humans thrive on these foods. In the vein of Michael Pollan, let’s simplify: Ferments are good for our health. Consume them. Every day.

For all practical purposes, when recommending ferments to clients, I suggest foods that are easily accessible and versatile to consume, personalized to digestive potential and gut function. Also, I recommend eating fermented foods a minimum of two, ideally three, times daily. Here’s a short list of ferments and how to eat them.

·      Yogurt, kefir, skyr, labneh, cottage cheese – on their own or with nuts, seeds, fruit; as a topping on savory foods like lentils, beans, roots and meals like tacos, stews.

·      Sauerkraut, kimchi – a side dish to many meals; topping for a tempeh Ruben or bratwurst; folded into yogurt, crème fraiche, hummus or tinned fish.

·      Kombucha, water kefir – mixed into sparkling water or mocktails

·      Pickles, asparagus and other veggies (naturally fermented) – as a snack

·      Miso, soy sauce, tamari – folded into cooked grains; sprinkled on veggies; mixed into sauces

·      Apple cider, umeboshi plum, balsamic vinegars – mixed into salad dressings or sauces