Espresso

I drank it in one gulp, and the bitterness made my whole face scrunch up. My colleague laughed beside me. He said this stuff isn't for quenching thirst — it's for staying alert. I didn't understand at the time. I thought it was expensive and bitter — what's the point of drinking it?

Later I gradually learned that foam is called crema. Italians call it the soul of coffee. In Italy, an espresso without crema would be sent back.

The word "espresso" itself is Italian. Many people think it means "express," as in fast, but that's not entirely correct. In Italian, "espresso" has two meanings: one is "pressed out," referring to using pressure to extract coffee; the other is "fast," because an espresso takes only about 25 to 30 seconds from start to finish.

The standard for modern espresso was established in 1948. The son of a Milan café owner named Achille Gaggia invented the lever-operated coffee machine. This machine used springs and levers to generate pressure, reaching 8 to 10 atmospheres — five to six times that of the previous steam machines.

What happens at high pressure? The oils and gases in the coffee are squeezed out and mix with water to form an emulsion that floats on the surface of the coffee — this is crema. Gaggia originally named this new coffee "caffè crema," cream coffee.

In 1961, Ernesto Valente of Faema company invented the E61, the first machine to use an electric pump to generate pressure. Valente had previously been a contractor for Gaggia, but the two parted ways due to disagreements. Gaggia thought espresso was a high-end product that should be sold to upscale cafés. Valente thought they should make affordable machines that everyone could use. The E61 used an electric pump to stabilize pressure at 9 atmospheres, a number that later became the industry standard.

Why 9 bar, not 8 or 10? No one can give a definitive answer. Some say 9 bar happens to extract the best flavor from coffee; others say it was a limitation of pump technology at the time. Regardless, 9 bar is now the default pressure for making espresso worldwide.

In 2009, I bought my first home coffee machine — a De'Longhi, model I forget, maybe EC155 or something, cost over a thousand yuan. That machine claimed 15 bar pressure, but the actual extraction pressure at the coffee grounds was probably only around 9 bar. Many home machines like to play up the pressure numbers, claiming 15 bar, 19 bar, 20 bar — it's all marketing. Too much pressure is actually bad; it over-extracts and makes the coffee bitter.

I used that machine for three years. Lots of problems. Temperature wasn't stable — the first and second cups could taste very different. The steam wand didn't have enough power for milk foam, producing coarse bubbles. The group head leaked. In 2012, I sold it and bought a Gaggia Classic, second-hand, previous owner had used it for five years, I paid 1,500 yuan for it.

In 2019, I switched to a Rancilio Silvia, another benchmark entry-level semi-automatic. The Silvia has a larger boiler than the Gaggia Classic, with better temperature stability. But the Silvia has an issue — the boiler temperature fluctuation cycle is quite long. If you don't understand the machine's temperament, it's easy to extract when the temperature is too high or too low, resulting in bad coffee.

Many people install a PID controller after buying a Silvia to stabilize the temperature. I didn't. I think learning to master the machine's own rhythms is part of making coffee.

Making a cup of espresso requires controlling many variables.

Choosing coffee beans is also a whole field of study.

Italians traditionally use blends of Arabica and Robusta. Arabica has complex flavors, high sweetness, and also high acidity. Robusta has simpler taste, is bitter, but has high oil content, producing thick crema. The classic Italian blend is 70% Arabica plus 30% Robusta; some Neapolitan-style blends have an even higher Robusta ratio with more bitterness.

The specialty coffee scene in North America and Northern Europe doesn't really use Robusta — they consider it a cheap bean. They prefer 100% Arabica, single origin, light roast. Espresso made from these beans has noticeable acidity and prominent fruit notes — completely different from the traditional Italian style.

I drink both. When I'm rushing in the morning, I prefer traditional Italian style — dark roast, chocolate and nut notes, makes a good latte with milk. In the afternoon when I have time to savor, I'll make a single shot of light-roast espresso, no milk, experiencing the bean's own character.

Roast level also matters. Dark-roasted beans produce more oils and thicker crema, but simpler flavor. Light-roasted beans preserve more origin characteristics, but thinner crema and more prone to under-extraction. For light-roast espresso, I usually use slightly higher water temperature and longer extraction time.