How Does Machine Espresso Work?
Machine espresso employs precise pressure and amazing filter technology to make the perfect cup of coffee. How exactly does it work?
In order to make espresso, hot water is forced under high pressure through finely ground coffee. The process is similar to that of making drip coffee. However, the pressure is the primary difference.
The Head of the Group
The group head is the portafilter you put in when making De’Longhi Gran Lattissima EN650.B: 1400W Espresso Machine. It is responsible for dispersing the water into the portafilter and controlling the pressure of the extraction. There are numerous kinds of group heads each with their own advantages and drawbacks. Some focus on temperature stability, whereas others on pre-infusion options, and others are designed to control the lever. There are some that come with a range of features, such as the E61, which is considered the classic choice among many baristas for its ability to offer multiple benefits in one package.
As you can see from the photo above the head of the group has a number of notches. It is possible to place your portafilter in these notches and then turn the head around to secure it. A rubber gasket is located within the notches to create a seal while you insert your portafilter. The notches on the head allow for an exact position of the portafilter which is vital to ensure an efficient extraction.
The group head not only lets you to put in your portafilter easily, but it also maintains an even temperature. This is accomplished by cycling hot water around the portafilter, and through the brew-basket, making sure that the temperature is constant to extract the coffee. This is important, as even a few degrees can make the difference between a good and excellent espresso.
The Pump
The motorized pumps used in espresso machines rotary provide nine atmospheric bar pressure needed to extract espresso. This is different from manual piston machines that rely on a lever. The pressure is created by drawing tap water from a reservoir and pumping it through a heat exchanger prior to it is shot through the ground coffee in the group head.
Pumps tend to be less expensive than piston-driven models, and they tend to last longer. However, both types of machines can become damaged due to excessive use and poor cleaning. They also add mechanical complexity and can lead to a high price tag on even the simplest models.
Certain espresso machines eliminate the pump completely and instead make use of steam pressure to make espresso. This can result in over-extraction because the boiler that makes steam also warms the water to boil. In addition, these machines frequently have to rebuild their pressure between cups, which takes time and energy.
Many espresso machines employ the rotary or vibration pump, which is a vibration model that uses a vibrating disc to create the pressure, and rotating models that push hot water through the grounds at high speed. Both models can make a great espresso, but rotary machines are quieter and more durable than vibration pumps.
The Boiler
The boiler is the part which heats the water to the ideal temperature for extraction. The steam produced will eventually reach the portafilter, which holds the espresso grounds. It is then funneled into the cup. The steam causes enough pressure to push the grounds of coffee through. This creates a layer crema on top. This is one of the main characteristics of a great espresso.
There are three kinds of espresso machines, each having different pumps and brew temperature. There are different ways to control the amount of brew, as well as the size of cup that can be made by the machine.
The first espresso machines were steam-type. They employed only one boiler to make both steam and brew however, the pressure they could produce was very low – just two bars of atmospheric pressure at most. This led to the coffee tasting bitter and burnt. The modern espresso machine was designed by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.
The most common espresso maker is a semi-automatic machine with an electric pump. These are the images people have when they think of an espresso machine. With a semi-automatic machine you must grind the beans and tamp them yourself but the pump regulates the flow of water and pressure. This is an excellent compromise between human touch and the mechanised quality.
The Filter
Typically, espresso machines use a filter to separate out the grounds of Sage Creatista Plus Coffee Machine: Stainless Steel Excellence when they pass through the hot water. The filter is also an essential part of the machine’s temperature control, since it helps to prevent overheating.
Filters also aid in flavor since it allows for an extended flowering time. This helps the beans to release their flavors and provides the chance for better extraction.
It is important to remember that even the best filter can produce a bad cup of coffee. The quality of the beans and the extraction process remain vital.
This is where the magic happens. It’s what makes espresso taste good. The grouphead (also called the brewhead) is where you put the portafilter, the device that you put the grounds of your coffee into when making espresso.
Steam-driven espresso machines make use of hot water that is heated inside an airtight container to create steam. The steam then pushes hot water into the grounds of coffee under high pressure. These types of machines are typically less expensive and easier to maintain than pump-driven models. They are however limited for creating the ideal conditions for brewing, as they operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.
In recent years, compressed air-pump-driven espresso machines have become more popular. They use an air compressor to force hot water through the grounds and are significantly more portable than steam-driven electric machines.
