How Does Machine Espresso Work?
The machine espresso makes use of precision pressure, and a filtering system that is awe-inspiring to make the coffee you love. How exactly does it work?
Espresso is produced by pushing hot water at high pressure through finely ground coffee. The process is similar to making drip coffee, however the main difference lies in the pressure.
The Group Head
The group head is the portafilter you put in when making espresso. It is responsible for dispersing water into the portafilter, and controlling the pressure of the extraction. There are many different types of group heads, each with its own advantages and disadvantages. Some are focused on temperature stability, whereas others on pre-infusion features, and others are designed to control the lever. There are also some that include a mix of features, such as the E61 one, which is the most popular choice among baristas because of its ability to offer multiple perks in a single package.
As you can see in the above image, the group head has numerous notches that you can place your portafilter and twist it manually to secure it. There is also a gasket made from rubber which is located inside the notches and helps create an airtight seal after inserting your portafilter into the machine. The notches on the head permit an exact positioning of the portafilter which is crucial for an efficient extraction.
The group head is not just able to allow you to put in your portafilter easily however, it also keeps the temperature at a constant level. It does this by cycling hot water through the brew container and around the portafilter, making sure that it’s always at the correct temperature for extraction. This is important because just a few degrees could make the difference between good and great espresso maker barista (made a post).
The Pump
The motorized pumps in rotary espresso machines provide the 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 pumping water through a heat exchanger and then through the ground coffee.
Pumps tend to be less expensive and last longer than piston-driven machines. However, both kinds of machines can deteriorate due to overuse and insufficient cleaning. Pumps are also more complex mechanically, which can increase the cost of even the most basic models.
Certain espresso machines can eliminate the pump completely and employ steam pressure to create espresso. The disadvantage of this is that the boiler that produces steam also increases the temperature of water to boiling, which can lead to excessive extraction. They also have to constantly rebuild their pressure in between cups. This requires energy and time.
Many espresso machines make use of a rotary or vibration pump. A vibration model utilizes the vibrating disk to create pressure, whereas a Rotary model pushes hot coffee through the ground at a fast speed. Both models can make a great espresso, however rotary machines are quieter and more durable than vibration pumps.
The Boiler
The boiler is the one that makes the water warm to the perfect temperature for extraction. The steam that is created reaches the portafilter, which holds the best espresso machine grounds. It is then pumped into the cup. During this process the steam generates enough pressure to push the grounds of the coffee through. This results in a layer crema on top. This is a sign of a good espresso.
There are three distinct types of espresso machines, each having a different type of pump and the temperature of the brew. There are various ways that the brew may be controlled and the size of the cup the machine is capable of making.
The first espresso machines were steam-type. The first espresso machines were steam-type machines. This led to the coffee tasting burnt and bitter. The modern espresso machine was developed by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.
The most commonly used espresso maker is a semi-automatic machine with an electric pump. These are the images people have when they imagine an espresso machine. Semi-automatic machines require you to grind and tamp the beans on your own while the pump controls the flow of water and pressure. This is an excellent compromise between human touch and mechanized quality.
The Filter
Espresso machines usually have filters that separate the grounds of coffee from hot water. The filter is also an essential component of the machine’s temp control, since it stops overheating.
It also helps with flavor as a filter lets you enjoy a longer bloom time. This helps the beans to release their nuances and gives the chance for better extraction.
However it is crucial to remember that even a top filter could result in a bad cup of coffee as the quality of the beans and extraction are crucial.
It’s here that the magic happens. This is the reason why espresso tastes so good. The grouphead, often called the brew head, is the place where the portafilter (the container you place the ground coffee into) is placed when making espresso.
In an espresso machine that is driven by steam, hot water is heated in an airtight container to create steam. Steam is then pushed through the grounds at high pressure. These machines are cheaper and are easier for the user to maintain than pumps-driven models. They are however limited in their ability for creating the ideal conditions for brewing, as they operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.
In recent years, compressed air-driven espresso machines have been gaining popularity. They use an air compressor to push hot water into the grounds and are more portable than steam-driven electric machines.