How Does Machine Espresso Work?
Machine professional espresso machine for home uses precision pressure and mind-blowing filter technology to make the delicious coffee we enjoy. How does it work exactly?
To make an espresso hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee but the difference is in the pressure.
The Group Head
As the name suggests, the group head is the place you put your portafilter in when making espresso. It is responsible for dispersing the water into the portafilter, and controlling the pressure that results from the extraction. There are a variety of types of group heads, each with their distinct advantages and drawbacks. Some are specifically designed for stability of temperature while others are specifically designed to handle pre-infusion. Others are built to control the lever. There are even some that come with a range of features, such as the E61 that is the classic choice among many baristas due to its ability to offer multiple benefits in one package.
As you can see in the above photo the group head is equipped with several notches. The portafilter is placed in these notches and then twist the head to secure it. A gasket made of rubber is positioned within the notches to create a seal when you insert your portafilter. The notches allow for precise placement of the portafilter. This is essential for an even extraction.
The group head does not just allow you to insert your portafilter easily but also maintains the temperature at a constant level. This is achieved by cycling hot water around the portafilter, and through the brew basin, ensuring that the temperature is always at the right level for extraction. It is important to realize that even a small difference can make the difference between a good and a great espresso.
The Pump
Contrary to manual piston machines which rely on a lever that pressurize water, the rotary espresso machines use motorized pumps to deliver the nine atmospheric bars of pressure needed for espresso extraction. The pressure builds up by drawing tap water from a reservoir, and pumping it through a heat exchanger before being pushed through the ground coffee in the group head.
Pumps are typically less expensive than piston-driven machines and tend to last longer, however both types of machines could be damaged by excessive use and inadequate cleaning. They also add mechanical complexity which can result in costly prices for even the most basic models.
Certain espresso machines eliminate the pump completely and utilize steam pressure to make espresso. This can lead to over-extraction as the boiler that makes steam also causes the water to boil. Additionally these machines are often required to rebuild their pressure between cups, which requires time and energy.
Many espresso machines employ either a rotary or vibration pump, with a vibrating model using a rotating disc to generate the pressure and rotating models that push hot water through the grounds under high speed. Both machines can make great espresso, however rotary machines are more stable, quieter and less likely to break.
The Boiler
The boiler is what is used to heat the water to the ideal temperature to extract. The steam that is produced reaches the portafilter that contains the ground espresso coffee and gets funnelled down into the cup. During this process the steam generates enough pressure to push the grounds of the coffee through. This creates a layer crema that is then poured over. This is one of the main characteristics of a good espresso.
There are three 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 could be controlled as well as the size of the cup that the machine can produce.
The first espresso machines were steam-based. They employed one boiler to make both brew and steam, however, the pressure they could produce was very low – just two bars of atmospheric pressure at the most. This resulted in the coffee tasting bitter and burnt. This is the reason why Milanese producers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.
The most popular espresso machine is a semiautomatic that has an electric pump. When people think of travel espresso maker machines, they imagine these machines. If you have a semi-automatic machine you grind the beans and then tamp them by hand. However, the pump provides regulated water flow and pressure. This is an excellent compromise between human touch and the mechanised consistency.
The Filter
Espresso machines usually use a filter that separates the grounds of coffee from hot water. The filter is also an essential part of the temperature control system as it keeps the machine from overheating.
A filter can also help with flavor, as it permits the beans to flower for a longer period of time. This allows the beans to release their flavor and improves extraction.
It is important to remember that even the finest filter could result in a poor cup of coffee. The quality of the beans and the extraction, remain crucial.
It’s here that the magic occurs. This is what makes espresso coffee machine Home taste so good. The grouphead (also known as the brewhead) is where you place the portafilter, which is the thingy which you put the coffee grounds in, while making espresso.
Steam-driven espresso machines use hot water that is heated in an airtight container to make steam. The steam then moves hot water through the grounds of coffee under high pressure. These types of machines tend to be cheaper and easier to maintain than pumps-driven models. However, they are limited in their ability to produce the ideal brewing conditions, since they are only operating at 1-1.5 bars of pressure, while the perfect shot requires 9-10 bars.
In recent years, compressed air-pump-driven espresso machines have become more popular. They make use of an air compressor to force hot water into the ground and are more mobile than steam-driven electric espresso machine black friday machines.