The definition of an espresso is a much debated subject, as people’s ideas of espresso vary according to their own taste perceptions. Almost every aspect of espresso making is up for discussion: from espresso blend to tamping technique to volume of the espresso. But then, espresso is an art and a barista is a skilled craftsman. This is why events such as the World Barista Championship are becoming increasingly popular, as each contestant is producing something original.
Even the origin of the word espresso is split into two camps; those who believe espresso simply means ‘express’ or ‘fast’; or those that believe it comes from the Italian verb ‘espressimante’ which translates as ‘especially prepared for you’ (made to order).
Nevertheless, there has been much scientific research into making the perfect espresso, or ‘God Shot’, and a set of parameters have been defined as to what an espresso should be:
- An espresso is made with between 6-8 grams of ground coffee
- The temperature of the water when first in contact with the espresso is between 90-95C
- The pressure of the water on entry is between 7-9 bar
- The volume of an espresso is between 1-1.25oz (28-35ml)
- The time it takes to brew the espresso is between 25-30 seconds
While meeting all these requirements alone will not make the perfect shot, they do serve as important guidelines, especially for beginners. Though there is considerable variance in each of these parameters, you should find the level within each parameter that works for you, your machine and your coffee, and aim to be consistent to that level.
An espresso is made with between 6-8 grams of ground coffee (or 12-16 grams for a double shot). The actual amount of ground coffee you use to make an espresso is dependent on the espresso machine. This is because, during the brewing process, the puck of coffee will expand and so it is necessary for there to be a gap between the puck and the dispersion screen of the grouphead. If there is no gap then the puck will not infuse evenly, as water will struggle to penetrate the coffee all the way to the perimeter of the portafilter.