Learning Coffee - Espresso

I recently got into espresso. For years, I’ve been brewing coffee with pour-overs and decided to take up espresso. I’m going to write a series that will follow-along as I learn how to make coffee. Let’s start with a primer and future entries will dive deeper into technical topics.

What is Espresso

Espresso is a coffee brewing method, where coffee is extracted using pressurized hot water. The resultant beverage is concentrated and highly viscous. An espresso machine provides the pressurized hot water that is necessary, although there exists manual methods of creating pressure.

From here, the espresso shot may be drank as-is or used as a component in the final beverage. In North America, it’s common to make a cafe latte beverage by adding steam milk.

Origin

Espresso was invented in Italy in the late 1800’s, where the first machines were steam-driven. Espresso began to spread throughout Europe by the 1950’s. And to North America in the 1980’s. It’s the most common form of coffee in Southern Europe.

It’s popularity grew during the time of industrialization and urbanization. It was popular method to quickly churn out coffee for factory workers during their breaks. This associated it with the Italian working class, which can be seen with the Italian diaspora today. In many “little Italy” centres, there have historically been an abundance of coffee shops serving espresso. Outside of these neighbourhoods, it’s more closely associated with third-wave coffee, a little more bourgeois.

Tech Specs

The Italian Espresso National Institute has parameters for what constitutes certified italian espresso:

Parameter	Value
Coffee	7 ± 0.5 g
Temperature after extraction	88 ± 2 °C
Temperature in cup	67 ± 3 °C
Water pressure	9 ± 1 bar (900 ± 100 kPa)
Time	25 ± 5 seconds
Volume in cup (including crema)	25 ± 2.5 ml

Note that this is single shot. In American coffee culture, most drinks are made with a double-shot. The only difference is that both the coffee dose and final volume are doubled.

Caffeine

As with all coffee techniques, caffeine depends on extraction parameters. However, espresso does not extract any more or less than brewed coffee, for a given dosage of beans. This should make sense, as the goal of coffee brewing is to extract flavour compounds at more or less the same rate; caffeine just happens to also be present and will be extracted as a side-effect.

To generalize, a double-shot will be around ~120 mg, which is equivalent to a cup of brewed coffee.

Dose

Dose is the terminology given for how much beans are used and how much output beverage. It can be anywhere from 2:1 to 5:1.

However, because espresso machines are required and they have relatively standardized equipment (portafilter), there is a small range for how much coffee beans should be used. For a single, this is around 7 g; for a double, around 14 g.

Use too much and your coffee with touch the brew head. This may cause channeling.

Use too little and it’s nonsensible: use a single if you’re brewing <10 g; don’t brew at all if you’re brewing < 5g.

“Espresso Roast”

Espresso is both the name of a brewing technique and a style of roast. This has caused undue confusion among the masses.

“Espresso” roast is simply a roast that is popularly used in espresso brewing in Southern Italy.

It’s not required to brew espresso using espresso roast, any roast will work, even light roast. There are no special beans, it’s just another coffee brewing technique.