What makes one person seek out the spiciest chillis, while another enjoys only bland foods?

When his family could never agree on what to eat for supper, science writer John McQuaid decided to find out more about the science of taste. Whitney Pipkin meets him for a meal

John McQuaid's book, 'Taste', examines the way that our food preferences are rooted in genetics and shaped by culture (Amanda Voisard/Washington Post)

Flaking a bite onto his fork, John McQuaid takes in the sight of the whole rockfish before him, its eyeballs, fins and tail visible beneath a chilli-dotted red curry sauce.

"This is an example of something I would never have eaten as a child," he says, noting the way the Thai lunch at Soi 38 in Washington DC stares back at him from a fish-shaped plate. "I just thought it was disgusting."

His 13-year-old daughter, Hannah, agrees. She prefers "mostly white foods", choosing pasta and cheese over just about anything else. Her brother Matthew, 15, is picky in his own way, but on the other end of the spectrum: he loves piquant and spicy foods such as Sichuan shrimp, and he even joined his father in tasting the world's hottest pepper for the purposes of research. But he won't eat fast food or burgers, leaving a family on the go with few options.

How did his children's tastes come to be in such vehement opposition? Did the two inherit different genes? Were they exposed to different foods in the womb? Why and how do our palates evolve, anyway?

For McQuaid, a Pulitzer Prize-winning science journalist, answering those questions soon had him fully immersed in the study of taste, a sense that, compared with sight or smell, had long been ignored by scientists despite our cultural preoccupations with it. The answers turned into his new book, Tasty: The Art and Science of What We Eat (Scribner).

Tasty tells the story of the evolution of flavour, from the first bite by a single-celled organism to the proliferation of flavour combinations that today's chefs are only beginning to unearth. In it, McQuaid wonders how our flavour preferences, rooted in genetics and shaped over time by a shared culture, remain as unique as our fingerprints. His search for understanding walks readers through an enthralling survey of taste. It starts with a close-up view of the "bizarre, Lovecraftian-looking" receptors on our taste buds that distinguish sweet from salty, bitter from sour, and umami, the pleasantly savoury note we get from cooked meat or mushrooms, which was added to the list in 2001.

Tasty tells us why George H W Bush banned the bitter brassica broccoli from the White House in the early 1990s (probably because of his genes and his personal taste receptors), how we came to drink cow's milk despite a natural intolerance (by letting it go bad first) and how all five of the senses feed our brains an all-encompassing message of flavour.

Though the book will probably draw a following of the food-obsessed, McQuaid, 53, is not one of them. His children's food preferences have for years left him and his wife, Trish Clay, eating at chain restaurants on vacation and serving as short-order cooks at their home in Silver Spring, Maryland. Feeding their children, McQuaid writes, had become "a Rubik's Cube challenge; only pizza satisfied everyone".

Our sense of flavour is like a snowflake or a fingerprint. It is unique (AFP)

McQuaid tackles the subject with a journalist's curiosity, delivering his findings through a narrative that starts with the prehistoric underpinnings of flavour. Although he might lose some gourmands on his trek through the Cambrian period, McQuaid picks them back up when relatives of Homo sapiens have their first communal cookout.

The application of fire to food radically alters the flavour equation. Those first flames quickly turned raw meat into flavourful processing power, allowing the brain, which guzzles a quarter of an adult's daily calories, to develop. Getting more calories faster freed early humans to do something other than chew all day and it opened up a new world of taste. Around the campfire, McQuaid writes, "taste, smell, sight, sound and touch coalesced into our own flavour sense – a new type of perception that helped give birth to the human form and to culture."

The book goes on to survey the biggest advancements in flavour over the ages, stopping to focus on a few. It touches on the advent of fermentation, which rivals fire in its ability to cultivate our boldest and most beloved flavours. Another section is devoted to the science behind our dangerous love affair with sugar.

Researching the book took McQuaid to the Brooklyn test kitchen of the New York restaurant group Momofuku and to Iceland for a bite of foul-smelling hakarl, a fermented shark flesh that depicts how "entire nations can come to love things that repel outsiders".

When he started writing Tasty three years ago, McQuaid wondered why no one had delved into the evolution of flavour before. One could argue, after all, that we've never been more infatuated with what we put into our mouths. But, a few pages in, he realised the challenge of crafting a digestible story that draws from so many scientific and sociological disciplines. "I was trying to cross-reference things that aren't usually cross-referenced," he says, which left him asking questions such as: "If you're a proto-human being and you're roasting a shank of meat for the first time, what was that experience like?"

Though McQuaid is far from a "supertaster" (the small group of people who are genetically disposed to experience flavour more intensely than average) but a "nontaster", who can hardly tell fine wines apart, he brings a background as an investigative reporter to the task of discerning flavour's origins.

McQuaid is a Pulitzer Prize-winning science journalist who has fully immersed himself in the study of taste (Washington Post) (Amanda Voisard/Washington Post)

Three years before Hurricane Katrina devastated New Orleans, he worked on a series at the city's newspaper, The Times-Picayune, with fellow reporter Mark Schleifstein, which predicted that a giant hurricane would one day submerge the city. Scientific as their projections were, McQuaid said he was stunned to see them come true. His first book, Path of Destruction: The Devastation of New Orleans and the Coming Age of Superstorms (Little, Brown and Company, 2006), written with Schleifstein, follows up on their gloomy forecast to tell how political, geographical and atmospheric factors converged to create a storm whose repercussions are still being felt. Before that, McQuaid contributed to a series on the global fisheries crisis for the same paper, which won a Pulitzer Prize in 1997. That series, about how a growing global appetite for seafood is depleting the ocean's stores, got him interested in food. He now lives in the Washington area, but says it was during his time in New Orleans that he picked up an affinity for seafood.

"It's not that spicy," McQuaid says of his pla chu chee (fried fish in red curry) lunch at Soi 38. "It's hot, but it's not super hot." The dish appears on the menu next to three peppers, signifying the highest heat level, but he is unfazed.

As recessive-gene nontasters, both McQuaid and his son have elevated thresholds for chilli heat. Naturally, they tested those heights by tasting the world's hottest pepper, the Carolina Reaper, for a chapter in the book devoted to our mysterious hankering for the hot stuff. "The burning spread over my tongue and around my mouth and became overwhelming," McQuaid writes of the painful, yet somehow pleasant, experience he shared with his son. "Voices around me receded."

McQuaid tackles the subject of taste with a journalist's curiosity (Washington Post) (Amanda Voisard/Washington Post)

Matthew tried to stop the burn by chasing it with buttered bread and, when that didn't work, ranch dressing followed by a lime. The capsaicin chemical that bludgeoned their heat receptors causes pain but then blocks it. That explains, in part, why spice-seekers keep coming back for more.

McQuaid has brought a small bottle of the hot sauce made from those peppers to lunch, in case, after reading his words, I am still masochistic enough to try it; I'm not.

He has also brought a few purple miraculin pills, made from a tongue-tricking ingredient he first tried while "flavour tripping" at a Chicago restaurant. Made from miracle berries, the substance blocks some sweet receptors while making strong acids taste sweet. (These I gladly try, and, sure enough, they make a lemon fished from a water glass taste like chiffon pie.)

Did all his experiments lead McQuaid to a solution for his family's dinnertime quandary? Not exactly. He still hasn't found a week's worth of menu items upon which his family members can agree. "It goes back to a sense of flavour being like a snowflake or a fingerprint; it is unique, yet it develops over the course of your lifetime," he says.

McQuaid's book ends by looking to a future in which scientists and chefs are only beginning to unleash the possibilities of flavour, using technology to pair ingredients that are chemically alike (oysters and kiwi, chocolate and caviar) but uncommonly combined into new dishes. After marrying such improbable flavours, perhaps they'll find a way to unite his picky eaters around a common meal. Or maybe they don't need to. Pizza, after all, has been around for a thousand years.

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