Espresso is a coffee brewing method in which the hot water is forced under pressure through finely ground and compacted coffee. This is a primary point of difference – generally, espresso machines operate at 9 bars, or 130.5 psi. Compare that to the 60 odd psi that fills a car tyre and you start to get the picture.
The next important point of difference is the ratio of coffee to water. Pourover, French press and their drip cousins generally use a coffee/water ratio between 1:15 and 1:17 – whereas espresso usually uses a ratio between 1:1 and 1:2.The drink:
So, intense pressure and a very high ratio – what do we get in the cup?
Espresso is a viscous, intense and concentrated ‘extract’ of the soluble oils, acids, sugars and other flavour compounds found in coffee. Correctly made espresso has a balance of intense acidity and deep sweetness, with a big body and thick mouthfeel. There are many things under the control of a barista – dose, yield, time, temperature, pressure, pressure profiling – it’s easy to get lost in a sea of variables, but because the brewing process is so extreme, tiny changes can have a profound impact on the tastes in the cup. Baristas manipulate these variables to get the (subjective) best out of a particular coffee.The term ‘espresso’ is often used inaccurately to describe a darkness of roast, a general fineness of grind, a specific blend of coffee, a type of coffee bean, or a country of origin. A company may have established a specific blend or style of roast designed for espresso and named it ‘Espresso Blend’ or ‘Espresso Roast’, and outside of the coffee world, the term ‘espresso’ is used to describe a disparate range of items that are not a drink, for example, cushions or curtains.
Do not let this confuse you – espresso is a drink, and a process – not a cushion!
The next entry will discuss the history of espresso, and how it came to be the dominant brewing style in Australia.
Until next time,