It gives bubbly its fizz, stilton its funk, Sauternes its noble sweetness. It instils umami in soya sauce and suavity in the tobacco of your post-prandial cigar. It raises bread, knits tempeh together, detoxifies buah keluak, and exalts your cup of tea, coffee or cocoa far beyond muddy brown water. It also happens inside you – in fact, you wouldn’t be able to live a normal life without it.
We’re talking about fermentation, of course. As global gastronomy trends continue their current swing towards sustainably and traditionally produced foods, home and restaurant cooks are readopting and retooling ancient culinary practices – and prime among these, for age, diversity and sheer effectiveness, is microbial fermentation.
Cooks mostly work at a macro level, herding and kludging handfuls of ingredients into submission. The modernist kitchen, with its thermometers and centrifuges, allows a tad more precision. In comparison, microbes employ enzymes to manipulate flavour and texture on a far more complex and fine-grained level, needing no extreme temperatures or conditions – just time. It’s no wonder cooks have befriended them since antiquity.
It is these millennia of coexistence and co-evolution with humans and their culinary activity that have led – science is not yet sure how – friendly microbes to “turn off ” the genes coding for lethal toxins, unlike their genetically very close cousins which still give us food poisoning. A few hundred species have become so “domesticated” that they live and thrive inside us, composing what doctors call the gut microbiome. Though far from giving us a final map of the microbiome, research heavily implicates it as having far-reaching influences on our immune system, metabolism, longevity and even brain functions.
Fermentation unlocks flavours, aromas and nutritive compounds otherwise inaccessible. Indeed, noted French chef Yannick Alleno believes that terroir – the rootedness of flavour in geographical and cultural origin – is most profoundly expressed by fermentation. In their recent book Terroirs: Reflections of a Chef, Alleno and co-author Marie-Claire Frederic, a fermentation expert, point out that many French foods depend on microbial action for their terroir-specific signature flavours: wines, cheeses, cured meats, sourdough breads.
Alleno ferments vegetables, cooks them sous vide, then concentrates their juices with various low-temperature methods, obtaining essences with extended “caudalie” – the persistent duration of aroma on the palate – and what he calls “wavelength”, an extra depth and resonance of flavour. In his view, fermentation “reveals all the textures and tastes of a terroir’s living material”, providing “nouns” acted on by the “verbs” of precise cooking.
Among the most ubiquitous and industrious “noun” generators are the lactobacillus species, found naturally in or on many ingredients. They add zip to everything from lambic beers and Shaoxing wine to cacao, yogurt and the It garnishes of the moment: kimchi and other lacto-fermented pickles now starring at a restaurant near you. Lactobacilli create an acidic, anaerobic environment hostile to “bad” microbes but favourable to friendly species, for the net result of shelf-stable pickles playing bright and sustained chords of sourness.
Another microbe, Aspergillus oryzae, is grown on cooked rice to make koji, the traditional starter for many Asian rice and legume ferments. Over the past decade, a salted koji slurry called shio koji has become hugely popular among Japanese cooks: it tenderises, deeply seasons and bestows umami on whatever it touches, as its enzymes break down proteins, carbs and fats to respectively liberate amino acids, sugars and fatty acids.
Many chefs are capitalising on koji’s power in intriguing ways. Momofuku’s David Chang uses it to make nut- and lentil-based miso analogues he has christened (and trademarked) “hozon”. Ohio chef Jeremy Umansky grows ghostly-white koji crusts on meat and seafood cuts, which attain charcuterie-like tenderness and taste intensity in just days. Other pioneers are using koji to transform protein sources such as cheese and eggs into wholly new foods and condiments.
It’s a safe bet that whole undiscovered countries of fermentation lie somewhere out there, given that microbes are the earth’s most abundant type of life form by several orders of ten, with new species being discovered all the time. This is really their world, and we’re just living in it – and reaping the delicious benefits.
Yeast, bacteria and moulds lie behind most food ferments. Here’s where they can be found in your everyday food.
VEGETABLE AND FRUIT PICKLES Virtually every culture has a veg or fruit pickling tradition to preserve seasonal abundance for the lean months. China, Korea, Japan, India, and countries in Eastern Europe and Central Asia are among the many with deep and diverse repertoires.
SEAFOOD Practically every coastal culture has indigenous seafood ferments, ranging from sauce, slurry and paste to chopped or whole pieces – for example, the fish sauces across the Asean region, belacan, Worcestershire sauce, Korean jeotgal and Iceland’s infamous ammonia-scented fermented shark.
LEGUMES Soya beans are the focus of many traditional ferments, such as soya sauce, miso, tempeh, natto and smelly tofu. Other legumes are fermented to make staples and condiments in Africa and Asia. Modern items include soya milk yogurt and vegan cheese analogues made from fermented nuts.
MILK PRODUCTS Dairying cultures around the world ferment milk or whey to obtain a huge array of foods with a gamut of flavours and textures, from French creme fraiche to ropey Swedish viili and lightly fizzy Russian kefir.
CHEESES Most cheeses derive flavour and acidity from initial lactobacillus fermentation. Yeasts and moulds join the party to produce the marbling, rinds or textural particularities of some aged cheeses.
GRAINS These include koji, sourdough starters based on wheat, rice or other cereals; sweet fermented sticky rice eaten across the Asean region; fermented porridges around the world; Thai fermented rice noodles; and beverage ferments such as beer and rice wine.
VINEGAR Acetic acid bacteria have been tamed for millennia to make vinegar out of countless sources: grains such as wheat, rice, millet and sorghum; fruit wines and juices; malted barley; sugarcane juice; coconut water; honey; and molasses.
CURED MEATS These include dry-cured meats such as salami, chorizo, hams and other European charcuterie, and many kinds of Central Asian jerky, as well as wet or semi-dry fermented meats eaten cooked or uncooked, such as Vietnamese and Thai pork sausages and cuts.
CHOCOLATE AND COFFEE Before cacao beans can be transformed into chocolate, the fresh pulp that cloaks them must ferment to induce the beans’ full flavour development. Traditionally left to wild yeasts, this is now being driven more precisely by some manufacturers with the help of yeast starter cultures. Similar fermentation occurs in coffee berry processing.
HIS SECRET SAUCE
At Ayam Piru Sauce Factory, a third-generation soya sauce scion tweaks the family recipe and produces an astonishing gem.
Cheah Cheow Beng is the somewhat maverick heir to a three-generation soya sauce business. As a teen, he learnt the traditional tau yew ropes: soya beans are soaked, cooked, mould-fermented for three days, then mixed with brine and left to brew alfresco for many months before being filtered. After inheriting the business from his father in 1999, who in turn got it from his father who migrated from Guangdong to Penang in the 1930s, he retuned the process, opting for non-genetically modified Canadian beans, and switching to pure cultured koji mould instead of the capricious and unpredictable natural airborne spores on which his grandpa relied.
In 2010, Cheah made an experimental batch of soya sauce with mineral-rich salt from Australia’s Lake Deborah, a five-million-year-old primeval ocean deposit. It turned out surprisingly delicious – and expensive. “Per kilo, sea salt was 40 sen, lake salt was 7 ringgit,” he says, shaking his head. “My first intention was not to sell the sauce… until I shared it with my friends, who said, ‘You must produce this!’”
What finally convinced him was the sauce’s effect on his family’s health. After his daughter started consuming it daily, she stopped succumbing to frequent bouts of flu and getting mouth ulcers. He found that his own stamina – he is an avid cyclist – had increased. “My mood changed, my blood pressure went down,” he shares, attributing all of this to the sauce’s probiotic effect.
He dips some sauce for me to sample, straight from under an opened vat’s gnarly-looking bacterial frosting. Its flavour is sweetly rounded, with all the umami but not the wheaty sharpness of a Japanese shoyu. He also pan-sears me a chicken breast: marinated in the sauce for just 20 minutes, it tastes like it had steeped for days. Perhaps most radically different from commercial sauces, Cheah’s brew is aged for several months after filtration but is not pasteurised, yet keeps well and indefinitely at room temperature.
Today, this light soya sauce is Cheah’s signature premium product, along with double- and triple-brewed versions.
He has learnt how to imbue the sauce with mushroom and seafood nuances. Shio koji and shoyu koji (starter spiked with soya sauce) are his latest test subjects, and new ideas are continually brewing in his head and his vats – thanks to a trillion infinitesimal, invisible sources of inspiration.