Fermented foods appear to be having a moment, yet again. Kefir is cool, sauerkraut’s gracing the slices of New York-style Reuben sandwiches across the country and kombucha is the comeback kid of the cultured world. It’s a new wave of fungal frenzy, fuelled in part by a yearning for the frugal ways of the past and in part by research findings that “good” bacteria in the gut are vital for overall health — and that cultured foods can help nurture those tiny bugs to happiness.
Yet ferments have never really gone out of fashion. Many delicacies we enjoy are fashionably off, with their complex flavours enticing us back for more. Cheese is ripened with the use of bacteria, and sometimes moulds, which give it the tastes and textures we love. Vanilla comes to us courtesy of cultures: it’s only when vanilla pods ferment that microbes transform the sugar glucovanillin into glucose and the deliciously aromatic vanillin flavour. And let’s not forget alcohol, which has been keeping us company since 5400 BCE, when Persians discovered the pleasures of fermented grapes.
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Since time immemorial, people the world over have been culturing food to preserve it, and fermented foods form a keystone in many food cultures. Fermented herring or surströmming is considered the national dish of Sweden, the Japanese turn soybeans into miso, a core part of their diets, and Mongolia’s traditional drink is airag, a beverage made from fermented horse milk.
But where once we fermented through necessity, increasingly we’re choosing cultured foods for their taste and health benefits, for the artisan way they’ve been crafted and for the chance it gives us to play the mad scientist in our own kitchens.
What is fermentation?
When a food is fermented, bacteria and some yeasts — or a combination of both — feed on the carbohydrates and convert them into alcohols and carbon dioxide or lactic acid. This process makes the food more digestible and more nutritious, creating beneficial bacteria, enzymes, vitamins and different strains of probiotics: live micro-organisms that offer health benefits when eaten in sufficient quantities.
It’s the sheer number of live bacteria, yeasts and moulds involved in the fermentation process that creates the diversity of fermented foods. According to Deirdre Rawlings in Fermented Foods for Health, ferments can be broken down into seven categories:
- Cultured vegetable protein. Generally made from legumes, such as soybeans, which are cooked, hulled, fermented and bound together with a mould that makes the soy easier to digest. An example is tempeh.
- High-salt, meat-flavoured fermentation pastes. Typically made from salty or savoury protein-bound grains and legumes, which are soaked, mashed, cooked and left to ferment. Most of these fermentations originated in Asia, such as soy sauce and Vietnamese mam, or fish sauce.
- Alcohol fermentations. In this process, sugars are converted into cellular energy by yeasts when placed in an oxygen-free environment, also creating alcohol and CO2. Wine comes from fermented grapes, rum from fermenting sugarcane, and whiskey, vodka and beer from fermented grains.
- Vinegar fermentation. When alcohol is exposed to oxygen, the bacteria known as Acetobacter start to convert it to acetic acid, or vinegar. This is what’s happened if you’ve ever left a bottle of wine open for too long; examples include apple cider vinegar and wine vinegars.
- Alkaline-fermented foods. In these less common fermentations, popular in Africa and Southeast Asia, the proteins in the raw ingredients are broken down into amino acids and peptide chains, releasing ammonia and increasing the pH of the product. This makes the end result, like the fermented ugba made from African oil beans, super stinky. Eat these near a window!
- Leavened breads. Dating from ancient times, leavened breads are those made from fermented grains, which use naturally occurring yeasts and Lactobacilli cultures to raise the dough. Unlike breads made with baker’s yeast, sourdough gets its sour taste from the lactic acid produced by the Lactobacilli in the starter.
- Lactic acid fermentation. One of the most important forms of fermentation, lacto-fermentation occurs when bacteria convert sugars into cellular energy and lactic acid, a natural preservative that inhibits “bad” bacteria. Examples are sauerkraut, cucumber pickles, olives, yoghurt and tofu.
By repeatedly fermenting a single product in a given place over long periods of time, artisans who craft fermented foods can domesticate local cultures. That’s what gives such foods or wines from specific regions their distinctive taste. San Franciscan bakers in the US nurture sourdough cultures that give their sourdough breads a flavour like no other; the appellations of origin given to French wines, for example, depend on the local yeasts, soils and cave conditions; and cheese-makers have for centuries been nurturing yeast strains to produce the best cheeses.
What are the benefits?
Aside from the food-preservation benefits of fermentation and the diversity of flavours it lends to our meals, a growing number of studies are showing that fermented foods are good for gut health and general wellbeing. The reasons behind this are the micro-organisms these foods contain — teeny-tiny bacteria that also inhabit our own bodies.
The human body is home to some 100 trillion types of different bacteria, according to the Human Microbiome Project, comprehensive research conducted by the National Institutes of Health in the US. About 80 per cent of these microbes live in our gastrointestinal systems. It’s the helpful bacteria in the gut that we rely on to carry out processes crucial for survival, such as digesting and breaking down food, producing antiviral substances and strengthening the immune system. Research is revealing that chemicals produced in the gut by the different strains of bacteria impact on not only your physical wellbeing but also your emotional and mental health via the vagus nerve, which runs from the gut to the brain.
Eating fermented foods daily supports health and vitality, and lacto-fermented foods in particular provide some serious health benefits. Lactobacilli produce their own natural enzymes, so fermented foods are already partially broken down when you eat them, helping to give your digestive system a rest. The bacteria also boost the vegetables’ natural vitamin content, produce antibiotics and cancer-fighting agents and help the healthy flora in the gut to proliferate.
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To reap the health benefits of fermented foods, start by adding a teaspoonful to each meal and gradually work up to one-quarter to one-half a cup of fermented veg one to three times a day. Be mindful that any foods that have been fermented using salt have a high salt content and should be taken in moderation.
To DIY or buy?
It isn’t difficult to ferment your own food, but there is a certain art to it. Leaving cut cabbage out on the bench for days at a time isn’t going to turn it into kraut, no matter how much you will it.
Many books are available to school you in the art of fermentation, such as Sandor Katz’s Wild Fermentation, Sally Fallon’s Nourishing Traditions, Deirdre Rawlings’ Fermented Foods for Health and Wardeh Harmon’s The Complete Idiot’s Guide to Fermenting Foods. You’ll need some basic equipment to DIY, including mason jars, salt, starter cultures such as whey and a good supply of fresh, clean water. We suggest building your confidence by exploring the basics first, such as making yoghurt or creating lacto-fermented veg.
Fermenting at home is good, creative fun, and don’t be scared about getting sick from your homemade cultured foods. Our society is one that has become terrified of bacteria of any description but remember that, until a few generations ago, fermentation was a common way to process foods. Fermented vegetables can even be safer than raw veg, mainly because the good bacteria from the fermentation process kill harmful bacteria.
For safe DIY, ensure you use fresh ingredients and wash vegies, hands, utensils, surfaces and containers well. A run through the dishwasher cycle will clean utensils and containers well enough. Also, temperature can be key when preparing ferments, so follow recipe-book guidance. When handling your food once it has been fermented, make sure you store it well, use clean hands — and don’t double-dip with your fork.
If you choose to buy, beware “fake” fermented foods that masquerade as the real deal, such as vegetables that have pickled in vinegar. These vegies have been preserved in an acidic mix but aren’t fermented so don’t offer the probiotic and enzymatic value of ridgy-didge fermented veg. Also, commercially preserved foods can be treated with pressure or heat, eg pasteurised sauerkraut, which kills off the health-promoting bugs present in correctly cultured goods.
Foods that have been fermented (and so pickled, too) will typically be in the refrigerated part of your supermarket or healthfood store. They’ll most likely cost more than they cost to make it at home, but the health benefits are worth it if you don’t have time to DIY.
Fermented foods are back for a reason: they’re cheap, great for your health, incredibly tasty and fun to make. Go forth and ferment!
