Standing on a hillside path above a rutted dirt road in northern Colombia, farmer David Castilla showed me a handful of beans cupped in his callused palm. Each pale yellow bean was the size of a small peanut. The mid-elevation zone has just the right blend of moderate precipitation and strong tropical sunshine for the beans to grow abundantly on smallish, glossy-leafed trees.

Like coca leaves, the beans are laden with a psychoactive alkaloid compound, a simple blend of carbon, hydrogen, nitrogen, and oxygen that is easily refined to a bitter white powder. Castilla was holding coffee beans, packed with caffeine, the world's most popular drug.

For hundreds of years coffee was used in its raw form — astringent and bitter — boiled or rolled with animal fat into a crude approximation of energy pellets. People clearly were chomping the coffee berries for the buzz, not the flavor. Yes, modern coffee tastes great. But it is 400 years of selective breeding and refinements in growing, harvesting, roasting, and brewing that have taken it from its unappealing natural state to the aromatic, smooth, flavorful beverage it has become. And without the caffeine, nobody would have bothered with the plant in the first place.

Castilla gave me a tour of his coffee farm, where dozens of glossy-leafed, evergreen coffee trees, eight to 15 feet tall, were growing in partial shade. Some of the trees had berries growing along their branches. The size and color of a cranberry when ripe, the fleshy berries envelop the seed that is the coffee bean.

This is arabica coffee, the species native to the mountains of Ethiopia, where it evolved with a blend of drenching rains, abundant sun, and a narrow band of acceptable temperature. Arabica is the smooth-flavored coffee Americans have come to love, the coffee that gourmet coffee connoisseurs swear by. The other common commercially grown coffee species is robusta, which is heartier and more productive and can grow in warmer temperatures, out in the open at low elevation. Robusta beans are often blended into commercial coffees, like Folgers. But virtually all Colombian coffee is arabica.

After a brief tour of the coffee farm, I sat with a small group on the cement patio where Castilla dries his coffee beans in the sun, next to his small house.

Then I caught a glimpse of a motion in the distance, through the trees. Soon I saw them coming down off the hill — a man and a mule. The mule carried a pack frame loaded up with two massive burlap sacks. They passed us, the man giving a benign wave. I couldn't help but think he looked somewhat familiar.

Soon after, it occurred to me why this was. He was reminiscent of a folk icon who rose from coffee's mid-century doldrums and came to its rescue, complete with white hat and handsome steed. But he was not astride the beast; he was leading it. And it was no horse; it was a mule. As you might have guessed by now, this folk hero is Juan Valdez, created in 1960 by the ad firm Doyle Dane Bernbach for the National Federation of Coffee Growers of Colombia.


The alliance between Colombian coffee growers and Madison Avenue admen grew from a desperate situation: a coffee market in crisis. This brings us to something counterintuitive. Despite Americans' conspicuous embrace of gourmet coffee (as exemplified by the Starbucks on seemingly every corner), our grandparents drank more coffee than we do. A lot more.

American coffee consumption peaked in the World War II years. Back then, coffee was flat-out winning in the competition against other beverages. Americans drank 46 gallons annually — nearly 20 pounds of beans per person.

But by the late 1950s, facing competition from Coke and other caffeinated soft drinks, coffee consumption was falling just as production was ramping up, leaving the market glutted and prices plummeting. In Colombia, coffee prices dropped by 50 percent.

At that time, only one in 20 coffee consumers even knew that Colombia was a coffee-growing country; the country of origin was of little consequence to coffee drinkers. Not only did roasters not boast of coffee's country of origin, but they preferred to keep it hidden, in order to have more flexibility to blend coffees.

That's when Juan Valdez trudged into newspapers and onto TV screens. Dressed like a simple but proud coffee grower, he emphasized the care farmers took to produce a high-quality cup of coffee. He showed how farmers picked coffee by hand and dried it in the sun. Valdez taught Americans to appreciate coffees of origin, or single-origin coffees, by emphasizing the difference between just any coffee and Colombian coffee. He became one of the best-known pitchmen of the era, alongside the Marlboro Man and the Pillsbury Doughboy.

The ads worked. Colombian coffee started selling at a premium, paving the way for the Starbucks generation of aficionados, who can name not only their favorite coffee-growing country but also the region, and maybe even the farm, where their beans were harvested.

Valdez revolutionized coffee sales by branding Colombian coffee. But he did something more, too. He established a coffee-sales narrative that has become the staple of the gourmet coffee story line: modest but hardworking farmers in far-off lands, proud to deliver you an exceptional cup of coffee.

Colombia produces 1 billion pounds of coffee annually, bringing more than $2 billion into the country each year and trailing only oil and coal in export value among legal commodities. But that is a small percentage of the annual worldwide coffee harvest, which now exceeds 19 billion pounds. That is enough coffee to fill more than a million dump trucks — parked end-to-end, they would reach from Seattle to Boston and back to Los Angeles. The industry is worth more than $70 billion annually.

This massive industry feeds an important, if not indispensable, part of most Americans' lives. To brew our average fix of nearly three cups of coffee daily, America imported 3.5 billion pounds of coffee in 2012, more than any other nation. The coffee Americans drink annually would fill more than 6,000 Olympic-size swimming pools.

If it's the flavor that makes us wild about coffee, why did our grandparents drink twice as much coffee as we do today? In those days the coffee was often roasted and ground long before it was consumed. And then it was run though a percolator, overextracting the bitter flavors. To most coffee lovers today, our grandparents' coffee was pure percolated plonk. It tasted worse, and they drank twice as much of it.

For most of us, though, it's likely that we are interested not so much in a flavor experience as in a cup of coffee that is, more than anything, unobjectionable. If we phrase the question a bit differently — asking not what makes a good cup of coffee, but what makes a cup of coffee good — the answer is easy: caffeine.

But most of us know little about caffeine. Even the most basic coffee distinction — between the robusta beans that become cheap diner coffee and the arabica beans that supply chic coffeehouses — is poorly understood. It's the lowly robusta that packs twice as much caffeine. Among the gourmet brews, people commonly perceive that a dark roast, with its strong flavor, has more caffeine than a mild-tasting, light roast. But that, too, is wrong. Because some of the caffeine has been burned off in the longer roasting, darker coffees have less caffeine than light roasts, bean for bean.

(Scott Areman/Corbis)

Picture a matrix with light roast/dark roast on one axis and gourmet coffee/diner coffee on the other; the least caffeinated of the four is the dark gourmet coffee. Most of us would guess the exact opposite. (Anyone looking for a good caffeine kick might choose a light-roasted Folgers blend.)
It seems weird that we lavish so much attention on the other aspects of the coffee experience: the Juan Valdez country-of-origin stories, for example. Because, really, they are window dressing. The object of our affection — the drug that makes us energetic, sociable, and happy — is obscured by the stories we tell about coffee.

What we don't talk about when we talk about coffee is the caffeine. And there is plenty to talk about. Bruce Goldberger, a forensic pathologist, got striking findings when he studied coffee. He bought a variety of coffee drinks and analyzed their caffeine contents, publishing the results in 2003. The caffeine concentrations varied wildly.

Goldberger found that the average caffeine concentration in specialty coffees was 12 milligrams per ounce. This equates to 60 milligrams per five-ounce cup of coffee, which is 40 percent lower than the standard established by a pair of Coca-Cola researchers in an oft-cited paper published in 1996 (they suggested that 85 milligrams per five-ounce cup of roasted-and-ground coffee should be the standard). But Goldberger pointed out that while the caffeine content is lower, serving sizes are generally larger. A five-ounce coffee cup is rare, indeed, these days, and a "small" coffee is generally at least 10 ounces.

Goldberger found caffeine differences between coffee brands. In his sample, a 16-ounce cup of coffee from Dunkin' Donuts had just 143 milligrams of caffeine, while a typical cup from Starbucks had twice as much caffeine. Espresso shots appeared to be more consistent in his study, at about 75 milligrams of caffeine per single (1.3-ounce) shot.

Goldberger's strangest result came from Starbucks. He bought a 16-ounce cup of coffee from one Florida Starbucks on six consecutive days. Each time, he ordered the Breakfast Blend, a mixture of Latin American coffees. The cup with the least caffeine had 260 milligrams. One cup had twice that amount. Yet another clocked in at a whopping 564 milligrams.

The caffeine varies for several reasons. Brewing strength — the amount of coffee used to prepare a cup — is one variable. The strongest coffee is made using more ground coffee per serving, as opposed to a weak cup of coffee that is as translucent as tea. (This is distinct from the roasting time: Both light- and dark-roasted coffees can be brewed on a continuum from weak to strong, depending on the ratio of coffee grounds to water.)

Caffeine also varies because no two plants are exactly alike. Differences in growing conditions and plant variety can lead to dramatically different levels of caffeine.

Goldberger's studies help to answer a question that many coffee drinkers have asked: Why is it that on some days one cup of coffee puts you in absolute equipoise — brilliant but steady, relaxed but energetic — while other days it is not even enough to prop open your eyelids? And on still other occasions, that very same cup — the same size, the same blend, from the same café — will send you to the moon, jittery and anxious, your heart skittering or pounding? It is because the caffeine levels in coffee vary dramatically, depending on the natural growing conditions, the variety of coffee plant, and brewing strength. To contrast it with a common delivery system of another well-loved drug, alcohol, it would be as if one bottle of wine delivered the expected 13 percent alcohol and another delivered five times as much, a dose stronger than gin, rum, or whiskey.

Caffeinated: How Our Daily Habit Helps, Hurts, and Hooks Us by Murray Carpenter. Reprinted by arrangement with Hudson Street Press, a member of Penguin Group (USA) LLC. ©2014 by Murray Carpenter.