The Ultimate Guide To Machine Espresso
The Ultimate Guide To Machine Espresso
Blog Article
How Does Machine Espresso Work?
Machine espresso uses precision pressure and mind-blowing filter technology to make the coffee we love. But how exactly does it work?
To make espresso, hot water is pushed under pressure through finely ground coffee. The process is similar to that of making drip coffee. However the pressure is the main difference.
The Head of the Group
The name implies the group head is the place you insert your portafilter when making espresso. It disperses the water into the portafilter and regulates the pressure of the extraction. There are a variety of types of group heads each with its distinct advantages and drawbacks. Some are focused on temperature stability, others on pre-infusion features, and others are designed to control the lever. There are even some that include a mix of features, like the E61, which is considered the classic choice among many baristas for its ability to provide multiple benefits in a single package.
As you can see in the above image the group head is made up of many notches in which you can place your portafilter and then twist it manually to lock it in. There is also a gasket made from rubber in the notches to help create an airtight seal after inserting your portafilter into the machine. The notches allow for an exact placement of the portafilter. This is essential for an even extraction.
The group head does not just allow you to insert your portafilter easily however, it also keeps an even temperature. It does this by circulating hot water through the brew container and around the portafilter, making sure that it's always at the right temperature to extract. This is vital, because even a few degrees can make the difference between excellent and great espresso.
The Pump
In contrast to manual piston machines that use a lever to pressurize water, Rotary espresso machines rely on motorized pumps that provide the nine atmospheric bars of pressure that are required for espresso extraction. This pressure builds up by drawing tap water from a reservoir, and pumping it through a heat exchanger prior to being pushed through the ground coffee inside the group head.
Pumps are generally less expensive and last for longer than piston-driven machines. However, both types of machines can deteriorate because of excessive use and inadequate cleaning. Pumps are also more complex mechanically, which can raise the price of even the simplest models.
Some espresso machines remove the pump completely and instead employ steam pressure to create espresso. The drawback of this is that the boiler that produces steam also raises the temperature of water until it reaches boiling which could lead to over-extraction. The machines must also constantly rebuild their pressure between cups. This requires energy and time.
Many espresso machines make use of either a vibration read more or rotary pump. A vibration model makes use of an oscillating disk to create pressure, whereas the Rotary model pushes hot coffee 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 what will heat the water to the ideal temperature for extraction. The resulting steam reaches the portafilter, which contains the ground espresso coffee and is then pumped down into the cup. The steam creates pressure to push through the grounds of the coffee. This results in a crema on the top of the espresso. This is the hallmark of a great espresso.
There are three distinct types of espresso machines, each with different types of pumps and brew temperature. There are many ways to control the brew and the size of the cup that can be made by the machine.
The first espresso machines were steam-type. They had one boiler to create both brew and steam, however, the pressure they could produce was very low - just two bars of atmospheric pressure, at most. This resulted in the coffee tasting bitter and burnt. This is why Milanese producers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.
The most well-known espresso maker is a semi-automatic one with an electric pump. When people think of espresso machines, they think of these machines. With a semi-automatic espresso machine, you must grind the beans and then tamp them by hand, but the pump provides regulated water flow and pressure. This is a fantastic solution that combines human control with mechanized reliability.
The Filter
Espresso machines typically use a filter that separates the coffee grounds from the hot water. The filter is also a crucial component of the temperature control system, as it keeps the machine from overheating.
A filter can also help with flavor, as it permits a longer flowering phase. This lets the beans release their nuances, and allows for a better extraction.
It is important to remember that even the best filter can make a bad cup of coffee. The quality of the beans, and the extraction process remain vital.
It's here that the magic happens. This is what makes espresso 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, when making espresso.
In the steam-driven espresso machine hot water is heated in an airtight tank to create steam, which then pushes the hot water through the grounds at high pressure. These types of machines are usually less expensive and easier to maintain than pumps-driven models. They are however limited to create the ideal brewing conditions as they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.
In recent years, compressed air-driven espresso machines have become more popular. They use an air compressor to push hot water through grounds, and are far more portable than steam-driven electric machines.