by John McQuaid
Pasteur’s adventure was the beginning of modern microbiology, the study of minute organisms ubiquitous in nature. Among them are bacteria, protozoa, algae, and fungi, including yeasts. Pasteur went on to make a series of scientific breakthroughs that exposed the hidden world of microbes and their role in diseases. He established the modern understanding of germs and vaccinations, which have eliminated or controlled many once ubiquitous infectious diseases such as polio and smallpox, saving tens or hundreds of millions of lives over the past century. But despite Pasteur’s continuing interest in beverage making (he wrote a book titled Studies on Fermentation: The Diseases of Beer, Their Causes, and the Means of Preventing Them), the field has fallen far short in one respect: very little is known about how microbes make flavor. Compared to the threat posed by disease, there has never been much urgency to study the benign biological underpinnings of cheeses or beers.
Which is why places such as the Momofuku Lab, which tease apart traditional techniques to see what makes them work, are so important. That effort is part of a broader reinvention of cuisine that is under way in restaurants and artisanal venues around the world, in which science and technology meld with old-fashioned kitchen intuition to push flavor into new domains.
This trend owes a lot to molecular gastronomy, a culinary movement that recasts cooking as chemistry. Conceived by Hervé This and physicist Nicholas Kurti, molecular gastronomy began in the 1980s, as This collected homespun cooking advice from a variety of sources—eighteenth- and nineteenth-century cookbooks, kitchen lore, old wives’ tales—and tested it in a laboratory, often the first time such conventional wisdom had been scrutinized scientifically. One of these truisms, which he called “culinary precisions,” was the notion that the skin of a suckling pig crackles more if the head is chopped off immediately after roasting, which This traced to a book by the eighteenth-century French gastronome Alexandre-Balthazar-Laurent Grimod de La Reynière. To test this nostrum—which he thought unlikely to work—This roasted four suckling pigs in a public experiment. To assure consistency, the pigs came from the same litter and had been reared on the same farm. They were cooked over a large outdoor fire for five hours. Two of the four heads were cut off, and members of the audience were invited to do a blind comparison. The skin of the headless pigs was, indeed, crispier. As This studied their carcasses, he realized why: when the pigs came off the fire, moisture evaporating from their flesh saturated and softened the skin. With the head cut off, the vapor escaped and the skin remained crispy.
In the 1990s and 2000s, This gathered scientists and chefs in a series of workshops to discuss the chemistry and physics of cooking, and how these could alter tastes, but also the body, brain, and mind. They began to experiment with both ingredients and the physical processes of baking, braising, frying, and microwaving to create new dishes that stimulated the senses in unexpected ways. This employed liquid nitrogen to make ice cream (rapid cooling produces a uniformly smooth texture) and calculated the perfect temperature to cook an egg (149 degrees Fahrenheit solidifies the white while leaving the yolk soft and smooth). Drawing inspiration from these meetings, haute chefs began to set up their own culinary labs. They juxtaposed unconventional ingredients and emphasized surprise. Spanish chef Ferran Adrià’s dishes included mango juice “spherified”—flash-frozen into a sphere—with a kind of salt obtained from algae until it looks like an egg yolk or caviar, and Parmesan cheese spun to the consistency of cotton candy.
“The act of eating engages all the senses as well as the mind,” wrote chefs Adrià of Catalonia’s elBulli, Heston Blumenthal of The Fat Duck in Bray, England, Thomas Keller of The French Laundry in California’s Napa Valley, and the esteemed food science writer Harold McGee. Their 2006 manifesto was an audacious attempt to map a twenty-first-century understanding of deliciousness in eight hundred words. The highest aim of cooking, they wrote, is to bring happiness and contentment. The way to do this is to mesmerize the senses, but in an era of sensory overload and networked information, the usual cooking techniques and traditions, not to mention the secrecy long associated with methods and recipes, no longer work. “Preparing and serving food could therefore be the most complex and comprehensive of the performing arts. To explore the full expressive potential of food and cooking, we collaborate with scientists, from food chemists to psychologists, with artisans and artists (from all walks of the performing arts), architects, designers, industrial engineers. We also believe in the importance of collaboration and generosity among cooks: a readiness to share ideas and information, together with full acknowledgment of those who invent new techniques and dishes.”
As early humans learned to manipulate flame and create the first recipes, flavor became the first crucible for culture. Today, deliciousness at its peak is an art form at the bleeding edge of high culture, a gateway to the sublime. The mysterious core of its creation, elaborate chemical reactions and the pulse of microbial life, makes it intrinsically more complex than art, music, writing, or filmmaking. Microbiology, genetic research, and neuroscience are making new tools available to shape sensory experiences, and to challenge and reinvigorate culinary traditions. Such efforts are ambitious, but also necessarily smaller in scale than the technologies overtaking the food industry. They’re also influential: since they inherited the mantle of high cuisine from the kitchens of royal courts in the nineteenth century, top-flight restaurants have, directly or indirectly, molded what everyone eats. Julia Child brought elite French cooking to a mass American TV audience; chain restaurants borrow the showy presentations of the elite. If the unusual dynamics of fermentation could be tamed by one test kitchen, others would follow.
The potentially hazardous nature of their moldy pork did not deter the chefs at the Momofuku Lab. “Failure is our bread and butter,” said Felder, who was the lab’s director from 2012 to 2014. Mistakes cracked open the culinary process, revealing how individual elements functioned, or failed to. To see if they had indeed failed, Felder sent butabushi mold samples to Rachel Dutton, a fellow at Harvard’s Center for Systems Biology who studied the behavior and genetics of fungi and bacteria. Dutton cultured the butabushi molds and extracted their DNA. She ran it through a gene sequencer, then compared the results to a database of known microbial DNA. The sample contained six species of fungi and two of bacteria. To everyone’s relief, none of them was dangerous. But the results were odd. She had expected to find Aspergillus oryzae, known to play an important role in katsuobushi’s flavor profile. Aspergillus oryzae is the mold in koji, the rice concoction used in Japanese cuisine. Instead, a wild fungus named Pichia burtonii predominated. It wasn’t something ordinarily found in raw or cured meat. “We don’t honestly know where it came from,” Felder said. “Whether it was just in the atmosphere or in the kitchen.”
The term “terroir” refers to the distinct sense of place that imprints itself on grapes, and ultimately on the flavor of wine: the lay of land and sea, the climate, changing patterns of winds and humidity, the soil chemistry. This includes the influence of the microbiome, the teeming universe of microbes that covers nearly everything in nature, whose composition varies mile to mile, yard by yard, and season to season. Any fermented food has its own terroir, and the Pichia fungus would carry a distinctive flavor imprint from the lab’s geographical location—lower Manhattan. The partners did not know what this would be like; city-bred microbes could yield terrible tastes. But when they tasted the butabushi, its flavor was good: savory, smoky, and funky like the fish version, but distinctly porky, too.
The Pichia discovery was a potential watershed. If its flavor-making abilities could be harnessed and exploited, along with those of other distinctly New York microbes, Momofuku could create American forms of Japanese cuisine instead of merely tinkering with the originals. It had taken ancient people centuries to tame microbes; now science might allow them to accomplish the task in months.
The first batch of butabushi had been a lark, but Felder, taking ove
r, resolved to proceed methodically. He ran a series of experiments to assess Pichia’s flavor-making abilities against the standard, Aspergillus. The results were disappointing: like an out-of-shape jogger competing against an experienced marathoner, Pichia performed miserably. In one test, Felder inoculated pork and beef with both molds. Bushi made with Aspergillus was superior in every way—taste, aroma, texture, and consistency—to that made with its rival. Aspergillus’s long history as a fermentation agent made it reliable and predictable; it produced consistently nice flavors—surprisingly, even in the unfamiliar territory of a new kind of meat. This was another new way to make bushi, and so had to be considered a success. But Felder was disappointed the Pichia had failed.
When he tried to re-create the flavor of the original butabushi, his efforts brought further grief. It didn’t taste the same. “It’s not the same environment, it’s not the same ecosystem that allowed it to become the dominant catalyst the first time,” Felder said. “We had isolated one variable, but not all of the others.” In other words, it wasn’t the Pichia alone that created the flavor the first time but its interactions with the other organisms—the chemical symphony of many metabolisms acting together.
These disappointments still offered valuable insights. They showed that microbes could not easily be brought to heel, while also suggesting a vast terra incognita existed for flavor and cuisine. “We know so little about endemic microorganisms,” Felder said, “that there’s limitless potential for what flavor compounds could be created.”
Felder kept up his microbial tinkering. (He also published a scientific paper on this work titled “Defining microbial terroir: The use of native fungi for the study of traditional fermentative processes.”) He made chicken bushi (a good flavor profile, but poor texture) and, after many failed tries, produced a decent beef bushi (a slight iron-liver flavor, but good texture). He swapped ingredients out of traditional Japanese foods to see what would happen: instead of rice, he used spelt, freekeh (a roasted green wheat), farro (a whole form of wheat), rye, barley, and buckwheat. Instead of soybeans, he tried pistachios, cashews, pine nuts, lentils, chickpeas, and red beans. Felder’s pistachio miso was green. It took many attempts to get it right, but it has become one of Momofuku’s signature foods, the sine qua non of its scientific fermentation efforts. Felder put a dollop of it on a spoon and I tried it. It was sensational: rich, yet light; complex and earthy, yet vivid.
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Dutton, meanwhile, expanded her microbial detective work from bushi to cheese. Two, sometimes three or more types of fermentation are employed to turn curds, the bland, chunky solids from milk, into a hunk of flavorful cheese. Several distinct communities of fungi and bacteria overlap and interact. And yet, “Cheese is relatively simple,” Dutton said. “If you compare the number of species of microbes in the human gut—in the hundreds if not over a thousand—to cheese, there are about ten. But because you have this simplicity and stability, when you make small changes there is huge flavor diversity.”
She began to collaborate with Jasper Hill Farm, an artisanal cheese maker in Greensboro, Vermont. Before dawn each morning, the staff pumps the milk from forty-six Ayrshire cows into a three-hundred-gallon vat in an adjacent farmhouse to be made into cheese. The warm milk is immediately seeded with a mixture of lactic acid bacteria, yeasts, and ripening agents. As bacteria begin to break lactose down to lactic acid, the milk turns sour. After about five hours, rennet, the solidifying agent, is added. One morning when I visited, cheese maker Scott Harbour dipped a knifelike tool into the milk, testing for signs the fats were about to condense into curds: a few minutes later the tank contained a shaking, shimmering solid. Harbour and a colleague hand-cut and lifted big hunks with the consistency of aspic onto stainless steel counters. It was mushy and mild, with only the slightest hint of acidity. The cheese makers compressed globs into cylindrical molds, which are set aside and flipped on a schedule so the whey drains out evenly, creating a consistent texture: a three-dimensional canvas for what comes next.
I had brought my twelve-year-old daughter, Hannah, to watch cheese being made. She loved comfort food, and cheese in particular, things with subtler, richer flavors harmonized by umami. If she had her way, her diet would be macaroni and cheese, grilled cheese sandwiches, quesadillas, pizza, and cheese ravioli dosed with Parmesan. It was hard to get her to eat anything else, and her pediatrician became concerned about the lack of variety. Eating less cheese only strengthened its allure, and it became a source of mordant comedy. She adopted “cheese” as a catchphrase and made her online avatar a wedge of Swiss.
At Jasper Hill, they were making a soft cheese named Winnimere. After the whey drains, the semi-solid cheese cylinders, about five inches in diameter, are cut into small wheels. In the basement, the next phase was under way: cheese makers wrapped a narrow strip of spruce bark around each wheel. They handed Hannah a hat and apron, and she started wrapping and snapping the bark in place with rubber bands. The bark helps it keep its form, while imparting a sappy, woody flavor and a set of microorganisms to the surface. As the cheese ages, these microbes—mainly penicillin molds—form a hardening rind with a mushroomy flavor. Sometimes a virus gets into a batch, infecting both molds and bacteria. The rind turns yellow and the flavor acrid, sour, and oniony. The molds also work their way inside the cheese, joining the lactic acid bacteria. Depending on the mix of microbes at each point inside, the flavor varies millimeter by millimeter.
Winnimere develops a signature sheen of pink and orange that is important for its brand identity, and catches the eye from crowded display cases. Dutton was trying to understand what, biologically speaking, those colors do. Her basic technique was straightforward: she grew cheese cultures in petri dishes, combined them, and observed their behavior. When she uncapped a dish, sharp, funky smells emerged with no cheese present. She walked us into a cool room where test cheeses are stored, dollops of curd arranged in a grid of tiny plastic wells, infused with different combinations of molds and bacteria. On one of them, a bright green penicillin mold grew next to a yellow colony of Arthrobacter, a common genus of bacteria usually found in soil. Dutton flipped the container over. A patch of bright pink was blooming out from Arthrobacter adjacent to another, unidentified mold.
“We want to know what that pigment is,” she said. “Why [Arthrobacter] is producing it. Does the pigment do something? Is it producing it to maybe try and harm the mold because it doesn’t like that it’s growing next to it, or is it just some sort of general protective response?”
Some microbe species develop a mutually beneficial relationship with others to survive. Some just compete. Both kinds of interactions produce distinct colors and flavors. Understanding those relationships could allow cheese makers to fine-tune their microbe wrangling, expanding the range and shadings of taste. But there are many obstacles. Even known microbes interact with a slew of environmental unknowns—as Pichia was before it was identified. It might be something on the grass the cows eat, or an airborne germ entering the aging vaults. This adds a dose of randomness to every batch. Jasper Hill had plans to follow the technique Dutton brought to Momofuku, identifying the source of its homegrown molds and bacteria. Most American cheese makers get their cultures from European manufacturers. Knowing the local microbiome would enable them to patent a distinct Vermont terroir.
To produce that terroir, aging must be carefully managed so that the microbes flourish in just the right way. Zoe Brickley, who oversees this process, took us inside a Jasper Hill vault. A low ridge had been excavated into seven caves, each projecting into the earth at a different angle off a central axis. Naturally cool and moist, they allow Jasper Hill’s cheese makers to orchestrate the emergence of flavor over weeks and months with environmental fine-tuning. Their temperatures range between 49 and 53 degrees, and the humidity is kept at 98 percent.
Wheels of clothbound cheddar, eighteen inches across and six inches high, were stacked on towering shel
ves. Virgin wheels are pressed into a burlap band. Then circles of cloth are applied to the top and bottom and rubbed with lard. This keeps them from drying, and also creates a home for molds, which multiply and turn the cheeses fluffy as the months pass (they’re vacuumed and scrubbed before they depart). Tiny bugs called dust mites burrow into the lard, exposing the burlap to air, which helps maintain the right balance of moisture on its surface. Ripening takes roughly a year: the cheeses on the shelves ranged from new to thirteen months old.
The air was loamy and thick, with a hint of ammonia and a floral scent from the mites. Flavors grew and morphed incrementally, each wheel on its own lonely trajectory. Brickley pulled one down, took out a small cheese-tapping tool, stuck it into the bottom, and extracted a sample. Unlike a typical mass-produced sharp cheddar, with a bitter tang and a hint of sulfur, this one was sweet, with a brothy, umami note. But it was also crumbly, a bad sign. “It’s sandy, it has a broken quality to it,” Brickley said. “I don’t see how that can get much better.” Bacterial fermentation had run wild inside this wheel, making more acid and reducing calcium and other minerals essential to a smooth texture. The next wheel was only a week younger, but it was completely different; like a civilization unto itself, each wheel’s microbial community rises and falls in its own way. This cheese was smooth, with a hint of pineapple flavor. Still, something was missing. “There’s not enough meat,” she said. “I think it’ll get more meaty, like white miso. I think of meats in a flavor, with white miso being the lightest, then chicken broth, then maybe pork, then maybe red meat broths.”
