An espresso is a specific way of preparing coffee: It is brewed using the steam pressure process and is characterized by its full-bodied, strong aroma. While in Italy and Spain coffee is brewed almost exclusively with espresso, in this country the drink is considered a small refreshment for in between. But how does an espresso machine work and how does the perfect espresso work? We answer these and many other questions in the following guide.
1. How does an espresso machine work?
Although the different types of espresso machines differ in their structure, they all work on the same functional principle. As soon as you turn on the My Espresso Machine, the water in the tank begins to heat up. When it is around 90 degrees hot, it is passed through the espresso grounds at a pressure of around nine bars. This is generated either by a lever or a pump. The variant with a lever is ideal for real coffee lovers, as the pressure can be varied as desired, which in turn affects the cream and the taste. So that the espresso powder is not washed out of the mold, it is held in place by the so-called “tamper” (a kind of tamper).
In most cases, port filter espresso machines are semi- automatic, so a separate grinder is required if you want to grind the espresso beans yourself. Fully automatic machines, on the other hand, have their own grinding system.
When it comes to heating the water, you have the choice between three different systems:
single circuit system
- There is only one container for heating water
- Sufficient for brewing espresso
- However, it is not suitable for preparing other coffee specialties such as cappuccino or latte macchiato (reason: different water temperatures are required for milk frothing and coffee)
dual circuit system
- Divided boiler (hot water and steam area)
- Allows espresso to be brewed
- Also suitable for other coffee specialties: coffee and milk froth can be prepared at the same time
dual boiler system
- Two separate boilers
- Suitable for brewing espresso
- Other coffee specialties can also be prepared: the temperature can be set separately for both boilers
- How do I make a perfect espresso?
Several components are decisive for the preparation of an espresso: The mixture, quantity, machine and degree of grinding have a decisive influence on the taste of the coffee.
According to the National Institute of Italian Espresso (inei) , the following criteria must be met for a perfect espresso:
- Coffee amount (ground): ~ 7 grams
- Temperature of the espresso when it exits the machine: ~ 88 degrees Celsius
- Temperature of the espresso in the cup: ~ 67 degrees Celsius
- Processing time: ~ 25 seconds
- Caffeine: 100 mg per cup
- Amount of coffee in the cup (including crema): ~ 25 ml
- Total fats: more than 2 mg/ml
- Flow ability (viscosity): at 45 degrees Celsius more than 1.5 mPa s (millipascal seconds)
- Pressure: 9 bars
However, these rules should only serve as a rough guide. Depending on the type of bean, changing individual parameters can lead to a better result. In addition, espresso machines are usually already set up to meet the criteria above as much as possible.
- Espresso variations
In addition to the usual espresso, which is called caffè in Italy and takes about two to three sips, there are numerous other variations that you can prepare with an espresso machine. We have put together the best known for you:
| Coffee corto / ristretto | Less than 2 sips, very strong espresso |
| Coffee lungo | Espresso diluted with a little water (4 to 5 sips total) |
| Coffee corretto | Espresso with some alcohol (usually Grappa) |
| Coffee macchiato | Espresso with a little hot milk |
| Coffee double | Double espresso |
