16 Must-Follow Instagram Pages For Machine Espresso Marketers
How Does Machine Espresso Work?
The machine espresso utilizes precise pressure and filter technology that is awe-inspiring to make the coffee you love. How exactly does it work?
Espresso is made by forcing hot water under high pressure through finely-ground coffee. The process is similar to making drip coffee. However it is the pressure that makes the main difference.
The Head of the Group
As the name suggests, the group head is the place you put your portafilter in when making espresso. It is responsible for dispersing water into the portafilter, and controlling the pressure of the extraction. There are many different kinds of group heads each with its particular advantages and disadvantages. Some focus on temperature stability, while others on pre-infusion options, and others are designed to control the lever. There are also some that contain a variety of features, like the E61, which is to be the most popular among baristas because of its ability to offer multiple perks in a single package.
As you can see in the above photo the group head comes with several notches where you place your portafilter and twist it manually to secure it. A gasket made of rubber is positioned within the notches to create a seal as you insert your portafilter. The notches allow for an exact placement of the portafilter. This is essential for an accurate extraction.
In addition to allowing you easily connect your portafilter, the group head is also responsible to maintain an even temperature. It does this by circulating hot water through the brew pan and around the portafilter to ensure that it is always at the right temperature for extraction. It is important to realize that even a small deviation can make the difference between a good and excellent espresso.
The Pump
Contrary to manual piston machines which rely on a lever to pressurize water, rotating espresso machines rely upon motorized pumps to provide the nine atmospheric bars of pressure that are required to extract espresso. This pressure builds up by drawing tap water from a reservoir and pumping it through a heat exchanger before being pumped through the ground coffee in the group head.
Pumps are generally less expensive than piston-driven machines, and tend to last longer, although both types of machine can degrade with overuse and insufficient cleaning. They also create mechanical complexity that can lead to costly prices for even the most basic models.
Certain espresso machines remove the pump completely and instead employ steam pressure to create espresso. This can lead to over-extraction as the boiler that makes steam also heats the water to boil. Additionally these machines are often required to restore their pressure between cups, which requires time and energy.
Many espresso machines utilize either a rotary or vibration pump, with a vibration model that uses a vibrating disc to create the pressure, and the rotary model pushing hot water through the grounds at high speed. Both machines can produce excellent espresso however rotary machines tend to be quieter, more durable and less likely to break down.
The Boiler
The boiler heats the water to the perfect temperature for extraction. The resulting steam reaches the portafilter, which contains ground espresso beans and is then pumped into the cup. The steam creates enough pressure to push the grounds of the coffee through. This produces a layer of crema that is then poured over. This is a sign of a great espresso.
There are three distinct types of espresso machines, each having distinct pumps and brew temperature. There are a variety of ways to control the brew and the size of cup that can be made by the machine.
The earliest espresso machines were steam type. They employed only one boiler to make both steam and brew, however the pressure they were able to produce was not very high - two bars of atmospheric pressure at the most. The coffee tasted bitter and burned. Read Much more is why the Milanese producers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.
The most commonly used espresso maker is a semiautomatic machine with an electric pump. These are the images people have when they think of an espresso machine. With a semi-automatic machine you have to grind the beans and tamp them by hand, but the pump regulates the flow of water and pressure. This is a perfect compromise between human control and mechanised reliability.
The Filter
Typically, espresso machines employ a filter to separate out the grounds of the coffee as they go through the hot water. The filter is also a crucial part of the temperature control system as it keeps the machine from overheating.
A filter also helps with flavor as it allows for a longer flowering phase. This helps the beans release their flavor and gives an opportunity for a better extraction.
It is important to remember that even the most efficient filter can produce a bad cup of coffee. The quality of the beans, and the extraction process, remain crucial.
It's in this area that the magic takes place. This is what makes espresso taste so delicious. The grouphead, sometimes referred to as the brewhead, is where the portafilter (the device you put the coffee grounds into) sits when you're making espresso.
Steam-driven espresso machines use hot water heated in an airtight vessel to create steam. The steam then pushes hot water through coffee grounds under 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 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, compressed-air-pump-driven espresso machines have become more popular. They use an air compressor to push hot water across the ground, and are more mobile than steam-driven electric espresso machines.