This story won a 2007 IACP Bert Greene Journalism Award.

T he odd pairing of zucchini and grapefruit is featured on the menu of New York City restaurant wd-50, with noodlelike strips of squid and a smear of sour cream. And get this —the zucchini is raw and the grapefruit is dehydrated.

Why? They’re more bitter that way. “Raw zucchini is more bitter than cooked zucchini,” says chef Wylie Dufresne. When you dry grapefruit, “the flavors become more concentrated.”

Not the usual way of thinking about those flavors. And yet more American chefs are bringing bitter into their menus, playing with the taste in bold ways. Pino Maffeo of Boston’s Restaurant L grates intensely bitter, black dried dandelion root over lobster. Pastry chef Ben Roche of Chicago’s Moto restaurant spikes coffee ice cream with a chemical compound that’s sometimes used in cleaning solutions to stop people from accidentally drinking them.

Before you assume these are dishes destined for the graveyard of failed experiments, know this: Customers love them. “When they see [dandelion root] on the menu, I think their eye just skips to the next word,” says Maffeo. “But then they eat it, and go, ‘Holy cannoli, what is this?’”

It’s a major shift in American taste. We’ve historically preferred foods that are salty and sweet (extra points for fatty) and, unlike most other cultures, shied away from bitter things. Think of Italians and Campari, or the Chinese and bitter melon. Yet in the recent past, American chefs were afraid even to breathe the “b” word for fear a dish wouldn’t sell.

Pastry chef Ben Roche spikes coffee ice cream with a chemical compound used in cleaning solutions to stop people from accidentally drinking them.

“What are you going to say when you describe something like an artichoke?” asks Dufresne. “That it’s bitter and metallic tasting? The average-Joe diner isn’t going to say, ‘Oh yeah, I’ll take two of those!’”

The signs are everywhere. Curls of bitter radicchio have gone from rarefied plates 20 years ago at Da Silvano to the menu boards of McDonald’s. There’s a Starbucks on every urban block selling espresso to people who ten years ago pronounced it “expresso.” Remember when practically all our chocolate was milk, except for Hershey’s Special Dark? Now the more-bitter dark is the fastest-growing segment of the American chocolate market, with ultra-dark varieties containing upwards of 80 percent cacao selling briskly. The trend was so overwhelming that it spurred Hershey’s to acquire boutique dark-chocolate-maker Scharffen Berger two summers ago.

Likewise bitter beers. Microbrews are gaining market share faster than less bitter mass-market lagers like Budweiser and Miller. The biggest category of entries at the Great American Beer Festival, the largest competition for commercial craft brewers in the country, is now India Pale Ales, or IPAs. These bitter beers typically have between 40 and 60 IBUs (International Bitterness Units, the measure of how much isomerized alpha acid a beer contains). Budweiser has about 10.

The country that invented American cheese, the Frappuccino, Jell-O, and Wonder Bread is finally discovering its dark side.

An evolutionary start

Until fairly recently, scientists believed we tasted things in different areas of our tongue. According to this “tongue map,” bitter was experienced at the back. Although the tongue-map theory has been debunked (we use our whole tongue to taste everything), it’s still believed to be true that bitter, along with sweet, salty, sour, and umami, the Japanese word that translates, roughly, to “meaty,” are the only tastes that humans can detect. All other flavors are experienced primarily through aroma.

Bitter in the Kitchen Here are some recipes that exemplify the use of bitter flavors. Negroni

Start with this classic Campari cocktail and bitter will never seem bad again. Fennel, Parsley, and Celery Salad with Preserved Lemon-Bitters Dressing

This is a new way to use Angostura Bitters outside the realm of cocktails. The combination of tastes in this dish—lemons, olives, the slightly sweet, anise flavor of fennel, plus the zing of the bitters—is complex and uncommon. It’s probably the most palate-testing recipe of the bunch. Baked Pasta with Radicchio and Mozzarella

This recipe combines flavors that you already know with a slight sweet-bitter edge. Saffron Panna Cotta with Bitter Honey

In this creamy dessert, depth comes from the slightly unexpected addition of bitter honey and saffron. But neither will overwhelm the dish, it’s nicely balanced.

We all hate bitter at first. Feed babies something bitter, and they’ll reflexively recoil no matter what culture they’re from, says Dr. Paul Breslin of the Philadelphia-based Monell Chemical Senses Center, which conducts research on the senses. Scientists believe this was once an evolutionary advantage that warned us away from eating plants containing bitter, poisonous alkaloids.

So bitterness is an acquired taste. But why do some acquire it, and others not? There’s no easy answer. In both Chinese and Indian traditional medicines, bitter foods are believed to be medicinal. This makes sense, as bitter foods like kale are often healthful, and strangely enough, even poisonous plants can be good for you. Foxglove, for instance, contains the poison digitalis, which is lethal in a large dose but heart medicine in a smaller dose.

This would explain the popularity of herbal aperitifs and digestifs in Italy. Originally, these liqueurs were created as health tonics. People associated them with feeling better (whether they actually worked or not) and in the process took a liking to them.

Others may warm up to bitter things because they really make one feel better. Think beer, chocolate, coffee, red wine, coca leaves —all bitter. “Straight black coffee just doesn’t taste that good,” says Breslin. “So what is it that makes people go from drinking their coffee with lots of milk and sugar in it, the way you do when you’re a young person, to drinking it black? It might be that they associate it with, basically, getting high.”

In and out of favor

Americans weren’t always averse to the taste. Around the time of the Revolutionary War, pubs routinely served a strong English beer called bitter. Many turn-of-the-century patent medicines evolved into bitter-flavored soda pop, notes James Trager, author of The Food Chronology: A Food Lover’s Compendium of Events and Anecdotes, from Prehistory to the Present (Owl Books, 1997). Moxie, which gets its flavor from bitter gentian root, was originally marketed as a cure for dementia and impotence. It evolved, briefly, into the most popular pop in the country (you can still find it, if you’re lucky). Coca-Cola, too, originally had medicinal claims and bitter notes.

A taste for bitter persisted, mostly in isolated pockets of immigrants, throughout the 20th century. (Chef Andrew Carmellini of New York City’s A Voce restaurant remembers his male relatives in Ohio chugging bottles of vermouth, dubbed by some at the time as “Italian mouthwash.”) However, for the most part, the American palate began to dull. Industrialized food production began in earnest during World War II. Regional cuisines were eroded or replaced by canned and processed foods.

“Food became bland, salty, overcooked,” says Amy Bentley, professor of Nutrition, Food Studies and Public Health at New York University. “Think ‘fruit cocktail.’” The longer you cook vegetables, the less bitter they are.

Chef Andrew Carmellini remembers his relatives chugging bottles of vermouth, dubbed “Italian mouthwash.”

A new palate expansion

Now we’re in the midst of a full-scale fruit cocktail backlash. Thank people like Alice Waters for promoting fresh, seasonal produce and local ingredients over canned and frozen. And thank the cultural shifts and affluence that have allowed Americans to travel the world and taste other cultures’ food. Also thank the recent waves of immigrants from Latin America and Southeast Asia who have introduced new foods to the States. Mainstream Americans, more and more, are looking for thrills and complexity in what they eat.

“Americans are finding more satisfaction, and a more hedonistic response to food, like the French,” says John Scharffenberger, cofounder of Scharffen Berger Chocolate. “They’re eating more intensely flavored foods,” like stinky cheeses, red wine, wheat bread, olives, curry, and chiles.

“Bitter being an equal part of a very small flavor perception, if you leave out essentially 25 percent of that, you are leaving out a huge range of flavors available to you,” says John Zearfoss, a professor at the Culinary Institute of America who has studied the unpopular taste.

In the company of other flavors

Here’s one thing every cook should understand: Bitter doesn’t like to be alone. Take mustard greens. On their own, they’re very bitter. But when made Southern style, they’re salted and stewed with pork to impart sweetness, then served with a side of sour lemon, lime, or pepper vinegar. The end result is savory, with a touch of bitter and a little sweet to balance.

Chefs who play with bitter understand this approach. “You kind of have to slip bitter in as a side note,” says Moto pastry chef Ben Roche. “It’s not a necessary part of the dish, but it kind of makes the dish.” He balances his coffee ice cream with sweet milk chocolate pudding and poached dates. Dufresne of wd-50 uses sour cream as a fatty, creamy balm to the bitterness of his grapefruit and zucchini, with brininess from the squid as an alternate foil.

David Myers, chef at Los Angeles’s Sona restaurant, marinates green papaya in bitters, then serves it with grilled lobster (sweet) and cooling cucumbers. Using bitters in a short rib braise “adds a punch,” says Myers, but they’re softened with tangy mustard, red wine, and tomatoes. Ron Mendoza, pastry sous chef at French Laundry, makes a bitter chocolate terrine paired with candied lemon peel (sour) and extra-sweet ice cream.

A fine balance

In some cases, finding the bitter balance is knowing when to pull back and when to be patient. “Bitter peaks throughout your meal are nice,” says Dufresne of wd-50. “I love the way you can use bitterness in the mouth to stimulate the palate and get people salivating and excited.”

Rick Bayless of Chicago’s Frontera Grill makes a sauce from dried guajillo chiles that’s sweet, salty, tangy, and bitter all at once. He coaxes this complexity by slow-cooking them with cumin, garlic, and black pepper. “A lot of cooks will try to make a 15-minute guajillo sauce, and all they get is the bitterness,” says Bayless.

“I love the way you can use bitterness in the mouth to stimulate the palate and get people salivating and excited,” says Chef Wylie Dufresne.

If you’ve acclimated your audience to these subtle bitter notes, you may be ready to go hard-core. Abhijit Saha, executive chef at the Park Hotel in Bangalore, India, recommends a bitter melon dish called bharwan karela. Peel a gourd, salt to drain bitterness in the way you would eggplant, and hollow out the center. Cook the seeds with onion; Indian pickling spices like fennel, nigella, fenugreek, and mustard seeds; and turmeric, chili, cumin, and coriander powders. Parboil the casing, put the cooked filling back inside, truss, fry in a small amount of oil, and sprinkle with chaat masala, a little lemon juice, and salt.

“Eighty percent of the bitterness will be reduced, and the remaining flavors come through, [tasting] artichoke-y or asparagus-y,” assures Saha.

On second thought, we Americans might want to stay in the shallow end for now. Somebody recently took bharwan karela to the Frontera Grill staff party.

“Cooks typically love all flavors, and we love things that are pretty far out there,” says Bayless. “But that bitter melon —oh my God was it bitter!”