Espresso

Espresso packs a whole lot into a receptacle barely larger than a thimble. It’s a drink with history—a high-pressure successor to the Turkish coffee of yore. It’s chemically quite complicated, including an emulsion of oil droplets, tiny solids suspended in water, and an intensely flavored layer of foam. And it’s pleasingly compact linguistically, too: The word espresso, in Italian, may mean any of “rapid”; “extracted”; and “[made] expressly for you”—all fitting descriptors for this tiny drink, made swiftly to order. By the way, it’s said es-presso, not ex-presso.

You’re supposed to drink espresso quickly, in thirty seconds or less, before its aromatic components dissipate, taking the flavor with them. But let’s linger over these teeny ceramic cups, and plumb their (surprisingly deep) shallows. Some things are worth savoring.

2.66: Calories in a one-ounce espresso shot—roughly equivalent to one grape

60-70: Approximate number of coffee beans per shot, weighing around 9 grams (0.32 oz)

10%: Proportion of crema in a shot of espresso

$0.20: Cost of coffee beans required for a single-shot espresso

5.7 hours: Half-life of caffeine in a healthy adult

20-30 seconds: Brewing time for a shot of espresso

63 mg: Approximate amount of caffeine in a single shot of espresso; an eight-ounce cup of pour-over may have three times as much

1,500: Chemical compounds in an espresso shot

14 billion: Espressos consumed by Italians each year, or about 275 per adult

1,000: Cups early espresso machines could make in an hour

£10 million: Amount the Costa Coffee chief taster Gennaro Pelliccia had his tongue insured for

Making espresso is all about the numbers, according to chemist and champion espresso-puller Chris Hendon, who spent six years developing the perfect formula. The most important thing, he says, is getting the grind right. If it’s too fine, the water can’t permeate properly; if it’s too coarse, the water doesn’t have enough surface area to connect with, limiting the extraction yield. (You can work out the ideal by attempting successively finer grinds, until you reach the point where the coffee starts to taste thinner again.)

Once you’ve got that right, it’s relatively smooth sailing—just make sure you don’t deviate too much from the numbers as historically defined by the Specialty Coffee Association. You want between 25 and 35 milliliters of water, or roughly an ounce, heated below boiling point to between 92°C and 95°C (197°F and 203°F). Water is then forced through the granular bed under 9 to 10 bars of pressure for around 20 to 30 seconds.

Visiting an Italian espresso bar? Here’s what to ask for. Don’t even think about ordering a latte—unless you’re jonesing for a big glass of milk.

☕️Liscio—smooth. Espresso, just on its own.
☕️Ristretto—short. Less water, more flavor, less caffeine.
☕️Lungo—long. Eked out with a little extra hot water.
☕️Macchiato—stained. Expect a splodge of milk on top.
☕️Corretto—corrected. A slosh of grappa or brandy is the big fix.
☕️Cappuccino—named for the hooded Capuchin monks. You know this one already. To be ordered before 11 am.
☕️Sospeso—suspended. You buy two espressos, and leave the second one “on order” for someone who may not be able to afford their own.

“Espresso consumption is an aesthetic experience, like tasting a vintage wine or admiring a painting. It is a search for beauty and goodness for improving the quality of our life.” —Andrea Illy, chairman of roasting company Illycaffè

“Unaccompanied children will be given an espresso and a free puppy.” —Ancient warning to negligent parents

Espresso was designed to be made and consumed quickly. Professional espresso machines use a maze of valves to transfer water from a pump to a boiler to the extraction plate, maintaining it at a high temperature and a very high pressure for extraction after extraction.

The high pressure is critical. First, it emulsifies oils in the coffee; second, it saturates the water with carbon dioxide created in the roasting process. The combination of those two things creates crema—the bubbly foam that gives espresso its complex taste.

Not all of the aromatics in espresso are delicious. If the extraction takes longer than 30 seconds, the amounts of 2,4-decadienal (rancid) and ethylgujacol (smoky) rapidly increase (pdf), which is why such a brew is considered over-extracted. The importance of carbon dioxide to espresso is why the beans should be freshly roasted and ground just before brewing.

1901: Milanese inventor Luigi Bezzera comes up with the espresso.

1906: Espresso goes global after being shown at the World’s Fair in Milan.

1933: Alfonso Bialetti patents the three-chambered moka pot; by 2016, one is in more than 90% of Italian homes.

1938: Italian barista Achille Gaggia files a patent for an early version of the modern espresso machine which replaces steam with hot-water pressure.

1947: Gaggia adds the now familiar spring-piston levers, which heightens the pressure and gives the world crema, as well as the expression “pulling a shot.”

1986: Fifteen years after it first opens, Starbucks adds an espresso bar to one of its stores.

2000: The inaugural World Barista Championship is held in Monte Carlo, Monaco, with a competitor from Norway taking first place. In two decades, it has never been won by an Italian.

2018: Starbucks opens its first Italian location, pledging “humility.”

For about a third of the population, coffee has a laxative effect. Perhaps surprisingly, it apparently has nothing to do with caffeine—instead, some unknown chemical seems to stimulate the distal colon, which in turn helps push waste out of the body. For better or worse, decaf should have exactly the same effect.

Located just outside Milan, the Collezione Enrico Maltoni has the world’s largest collection of whizz-bang vintage espresso machines, with more levers and buttons than most modern baristas would know what to do with. Make a visit if you can; otherwise, marvel at the images online and pick your favorite of the gleaming machines. Pour-over never looked so lackluster.