How Does Machine Espresso Work?
The machine espresso makes use of precision pressure, and filter technology that is awe-inspiring to make the coffee you enjoy. How exactly does it work?
Espresso is made by pushing hot water at high pressure through finely-ground coffee. The process is similar to making drip coffee but the key difference is in the pressure.
The Group Head
As the name suggests the group head is where you place your portafilter while making espresso. It distributes water into the portafilter and regulates the pressure during the extraction. There are a variety of group heads, each with its own advantages and drawbacks. Some are specifically designed for temperature stability while others are specifically designed to handle pre-infusion. Some are designed to control the lever. There are also some that come with a range of features, like the E61, which is considered the standard choice for many baristas because of its ability to provide multiple benefits in one package.
As you can see in the photo above the group head is made up of several notches to put your portafilter, then twist it with your hands to secure it. There is also a gasket made of rubber that resides inside the notches, which helps create an airtight seal after inserting your portafilter into the machine. The notches on the head allow for a precise placement of the portafilter, which is essential for an even extraction.
The group head not only allows you to insert your portafilter easily however it also keeps the temperature at a constant level. It does this by circulating hot water through the brew basket, and around the portafilter to ensure that it is always at the correct temperature for extraction. This is important, as even a few degrees can mean the difference between good and excellent espresso.
The Pump
The motorized pumps in rotary espresso machines supply the nine atmospheric bar pressure required to extract espresso. This differs from manual piston machines that use a lever. The pressure builds by removing tap water from a reservoir and pumping it through a heat exchanger prior being shot through the ground coffee in the group head.
Pumps are typically less expensive than piston-driven machines, and they tend to last longer, but both types of machines may degrade with overuse and insufficient cleaning. Pumps are also more complicated mechanically, which can increase the cost of even the most basic models.
Certain espresso machines utilize steam pressure instead of a pump to brew espresso. The disadvantage of this is that the same boiler that produces steam also increases the temperature of water to boiling and can result in excessive extraction. In addition these machines are often required to rebuild their pressure between cups, which takes time and energy.
Many espresso machines use either a vibration or rotary pump. A vibration model uses a vibrating disk to generate pressure, whereas the circular model pushes hot liquid through the ground at high speed. Both types of machines can make excellent espresso, but Rotary machines are quieter and more durable than vibration pumps.
The Boiler
The boiler is the element that heats water to an ideal temperature to extract. The steam that is produced reaches the portafilter which holds the ground espresso and is then funneled down into the cup. During this process, steam causes pressure bean to cup espresso machine push through the coffee grounds. This results in a layer crema on top. This is the hallmark of a great espresso.
There are three distinct types of espresso machines, each with a different type of pump and the temperature of the brew. There are also different ways in which the brew can be controlled and the size of the cup that the machine can make.
The first espresso machines were steam-based. The first espresso machines were steam-type machines. The coffee tasted bitter and burned. This is why Milanese producers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.
The most commonly used espresso machine is a semiautomatic that has an electric pump. When people think of espresso machines, they envision these machines. Semi-automatic espresso machine machines require you to grind and tamp the beans by yourself The pump, however, regulates the flow of water and pressure. This is a fantastic compromise between human control and mechanized reliability.
The Filter
Espresso machines typically have a filter that separates the coffee grounds from the hot water. The filter is also an important element of the temperature control system, since it helps prevent the machine from overheating.
A filter also improves flavor because it allows for a longer flowering period. This helps the beans to release their nuances and gives the chance for better extraction.
However it is crucial to remember that even a good filter can produce a bad cup of coffee as the quality of the beans and extraction is still essential.
This is where the magic happens, it's the thing that makes espresso taste great. The grouphead (also called the brewhead) is where you place the portafilter - the thingy that you use to put the coffee grounds into, when making espresso.
Steam-driven travel espresso maker machines use hot water heated in an airtight container to produce steam. The steam then pushes hot water through coffee grounds under high pressure. These machines are cheaper and easier for the owner to maintain than pumps-driven models. They are however limited in their ability to create the ideal conditions for brewing as they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.
In recent years, espresso machines driven by compressed air-pump have become increasingly popular. They make use of an air compressor to push hot water across the ground and are more mobile than electric steam-driven espresso machine with grinder machines.(Image: https://cdn.freshstore.cloud/offer/images/778/2223/quest-36569-espresso-coffee-machine-with-milk-frother-1-2l-water-tank-and-drip-tray-steam-ready-and-temperature-indicator-for-ground-coffee-beans-15-bars-of-pressure-2223.jpg)
