Re-Engineering Espresso

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3 9 月, 2007

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华尔街日报的软文（貌似），原文地址：http://online.wsj.com/article/SB118852179945214163.html

Re-Engineering Espresso
The Complex World of Coffee Research and the Quest for a Better Shot
By JEFF GROCOTT
August 31, 2007; Page W8

Since the dawn of coffee, humanity has taken few breaks in its quest for a better cup.

Our inaugural coffee buzz, according to legend, came after a shepherd in Africa noticed his goats grew frisky after eating the fruit of a certain bush. Early fanatics took theirs straight, chewing whole, raw beans. Then came roasting, grinding, steeping in water, and the skinny white-chocolate half-caf Venti.

The search continues. In September, Italian roaster Illycaffè will introduce a coffee machine in the U.S. Called Hyper Espresso, it pairs a custom machine (produced by Illy, $600 to $800 for home versions) with a coffee-filled plastic capsule (also made by Illy).

Like other single-serve systems, including Nestlé’s Nespresso and Kraft’s Tassimo, it’s meant to make it easier for groggy consumers or harried waiters to make a serviceable cup. But it also represents a departure: Current one-cup setups take the familiar brewing process of an espresso or drip coffee maker and put it inside a disposable disc or cartridge. Illy’s system, on the other hand, tweaks the espresso recipe — changing parameters like temperature and pressure that baristas and jittery espresso geeks long considered absolute.

It also moves Illy’s coffee into eye-popping price territory. The company figures Hyper Espresso cartridges will cost home users about 75 cents a shot. That’s the equivalent of $50 a pound of beans, compared with, say, $10.45 for a pound of Starbucks Italian Roast.

The goal is to position the company for a bigger slice of the market in coffee-filled capsules and cartridges; Illy already makes espresso “pods” for a variety of machines. Though the single-serve segment is a small part of the $7.8 billion U.S. retail market in whole beans and ground coffee, it has grown about 65% a year since 2001, to $99 million last year, according to Datamonitor/National Coffee Association of U.S.A.

For science nerds or anyone who’s tried even briefly to impersonate a Roman barista, the new system represents some noteworthy physics. Illy hasn’t exactly split the atom, but the company that more or less taught the world how to make espresso is now rewriting the rules.

“Illy was doing espresso education before anyone else,” says Bruce Milletto, president of the American Barista & Coffee School in Portland, Ore., which trains more than 200 baristas and coffee-shop owners each year. “There’s only one way to prepare espresso — it’s chemistry and physics.”

Over the decades, Illy’s researchers say they have isolated no fewer than 114 factors, from coffee growing to brewing, that must be controlled to make one good shot. Fresh beans must be ground and tamped just so, before exposing .25 ounces’ worth to one ounce of water at 194 degrees Fahrenheit (give or take three degrees) and nine bars of pressure for 30 seconds — in a clean machine, per favore! Do so and you get a shot of rich, but not bitter, espresso, topped with a tiger-striped layer of coffee foam that Italians call crema. Bungle a step and it’s, how do you say in English, swill.

Much of Illy’s thinking occurs in company labs in the hills outside of Trieste, Italy. With the aid of some quarter-million-dollar machines (mass spectrometers, gas chromatographs), researchers there have isolated and analyzed more than 1,000 volatile compounds that lend espresso its smells, says Illycaffè chairman Andrea Illy, the company’s third-generation head and a chemist by training. Good aromas tend toward chocolate, almonds and peaches. There’s also linalool, a jasmine-like scent that Mr. Illy calls “the ultimate flowery aroma.” Undesirables include wood (which can signify too-high brewing temperatures) and green peas (a sign of bad beans).

A few years back, the researchers also identified a crisis that legions of coffee drinkers never knew they had.

With traditional brewing, the scientists knew, water is forced through a bed of packed coffee grounds. As this hot, pressurized water percolates through the grounds, it picks up emulsified oils, bubbles of carbon dioxide, water-soluble compounds and even tiny bits of coffee bean. The result, in lay terms, is a shot of espresso.

Dissected Pucks

But having dissected spent espresso pucks, the scientists knew that water doesn’t percolate evenly through the grounds. Instead, it flows where there’s the least resistance, like rain running down a hill in rivulets. Water courses through some grounds while leaving others practically dry.

To Illy’s ground control team, this was the problem. Not every piece of bean was yielding up its peaches and linalool. Other parts of the coffee grounds were being flooded, thinning the espresso’s taste. So some 15 researchers and engineers undertook what became a four-year espresso reinvention. “We had coffee geysers,” Mr. Illy says.

The system they came up with works like this: Hot water goes into a coffee-packed capsule. Instead of merely dripping out the bottom and missing grounds along the way, as in Old Espresso, the water stays put. Pressure builds. All of the grounds, Mr. Illy says, are infused.

Once the pressure inside the Hyper Espresso capsule hits a certain level, a small valve inside it opens. (Illy has taken out international patents on this valve). Then the coffee spurts out into a second chamber (more patents) where it bounces against a plastic wall and aerates, creating lots of crema. (For aficionados, a thick layer of crema marks a good cup.)

And there it is — espresso blasphemy. Two brewing chambers instead of one. In scientific terms, the process is no longer percolation, but extraction. And one more thing: Because high pressure, not hot water, is doing much of the work of extracting the desirable stuff from the grounds, Illy has found it can lower the brewing temperatures of its machines by about five degrees Fahrenheit, resulting in what it says is a better cup. Fifty years of espresso rules — dio! the 114 steps! — out the window.

Others in the single-serve niche are also adding new touches. Next month, Nestlé, whose Nespresso machines work at higher pressures than most home espresso makers, will roll out Lattissima cappuccino-and-latte machines — with a removable milk container that can be kept in a fridge. Italian roaster Lavazza recently introduced a single-serve system, Blue, that it says replicates traditional espresso brewing. For now, it says, it’s for places like offices and restaurants, not homes.

Crema, No Sugar

Illy’s machine and capsules will debut in coming weeks in the kitchens of more than a dozen New York restaurants, including Nobu, Lever House and the Michelin three-starred Le Bernardin. Other restaurants around the U.S. will follow, Illy says. The company will offer home machines next spring.

We saw a couple of Hyper Espresso machines at Illy’s New York offices — admittedly not neutral tasting grounds. The hardware was operated by barista Heidi Rasmussen, a quality-assurance manager for Illy Caffè North America. Before drinking, she gave us an espresso-tasting primer, identifying aromas we’d probably notice, such as toasted bread and lemon.

Ms. Rasmussen pulled a few shots of traditional espresso, using the company’s standard beans, freshly ground. It tasted mellow and nuanced, like — maybe it was the power of suggestion — toast and lemon. The crema was thick. We skipped milk or sugar.

Then she made two shots of Hyper Espresso. For one, she used a restaurant-grade machine modified to take Illy’s capsules. For another, she used the home Hyper Espresso machine, made by Illy’s Francis Francis! division, that the company will introduce next year. Those shots, too, were mellow and nuanced. We tasted toast, and more lemon.

Back at Illy’s labs, the scientists say that while Hyper Espresso is made with the same blend of beans, it is empirically different than the traditional stuff. Thirty seconds after a shot is made, Hyper Espresso’s crema layer has 70% more volume and 20% more height than a traditional shot, they say. The crema lasts up to an hour instead of five minutes. (True enough, in our experience.)

And unlike beans brewed in the traditional maker, which the white coats found to have more chocolate and toasted-bread tastes, Hyper Espresso has more flowery aromas, thanks to a boost in compounds like linalool. Which version a person likes better is a matter of taste, Mr. Illy says. As for the cost, he says, it’s still cheaper than buying a coffee in a café.

The upshot: We detected subtle differences between Old Espresso made by a ringer barista and Hyper Espresso from a capsule. For those without home access to a ringer barista, the capsule might do as a stand-in. The downside for home users is that only Illy’s coffee fits into its machines, so owners who tire of Illy’s blend will have to fire up a second coffeemaker for a change of taste. Or, they could wait for coffee’s next leap forward.