The espresso machine has a system that forces a jet of hot water, at high pressure, to pass through a compact mass of very fine coffee powder. The key word there is “pressure”. The big difference between espresso coffee and homemade strained coffee is that in the latter the hot water passes through the strainer moved only by its own weight, while in espresso pressurized water produces a stronger, denser and more sparkling coffee, which many people find superior to coffee. strained coffee. “To be really good, an espresso depends on the three Ms of coffee: the Mixture, the Machine and the Hand”, says engineer Osmar Luiz Pecchio, who has worked in a Brazilian espresso machine factory for 20 years. The “blend”, in this case, is the coffee itself, which must have a correct combination of different types of beans.
The “machine” has to be well regulated and the “hand” is the experience of the person who takes the coffee, fundamental to regulate the amount of powder and compress it in the right measure. The espresso appeared in 1901, when the Italian industrialist Luigi Bezerra thought of a method to reduce the “coffee break” of his employees. He developed a machine that used pressurized water in a boiler to pass through the powder, making coffee ready faster – hence the name «espresso».
pressure cooking Water used in the beverage is compressed to up to 9 atmospheres
Filter
The water used in espresso passes through this filter before entering the machine, to eliminate any undesirable taste.
Manometer
It allows checking the pressure of both the boiler and the water that comes out of the electric pump and is used in the beverage. The latter should be between 8.5 and 9 atmospheres to have a tasty coffee.
Electric pump
The filtered water enters this pump, from which it leaves under high pressure and is divided into two: one part fills the heating boiler and the other will be used to make the coffee.
copper boiler
When the machine is turned on, part of the water fills this boiler up to a certain level, leaving space for the steam that will accumulate. An electrical resistance heats the water. Thermostats regulate the temperature of the steam, which should be around 119ºC
coffee water
The water to make the drink circulates in metal tubes (in red), which pass through the boiler, where the liquid is heated to 90ºC. When you press a button, part of that water goes towards the extraction group, where the coffee powder is left.
cup warmer
Many professional machines come with a cup warmer, a space on top of the machine that uses the boiler’s own steam to keep dishes warm.
extraction group
In this small removable compartment, the person puts and compresses the coffee powder, then inserting it into the machine. A machine can have from one to four extraction groups
water tube
You can use this output to get hot water, without coffee, to make tea, for example.
steam tube
Also called “cappuccinator”, this pipe allows extracting steam directly from the boiler. It is generally used to bubble milk, making cappuccino foam.