Let's Get It Out Of The Way! 15 Things About Machine Espresso We're Fed Up Of Hearing
Let's Get It Out Of The Way! 15 Things About Machine Espresso We're Fed Up Of Hearing
Blog Article
How Does Machine Espresso Work?
Machine espresso employs precise pressure and incredible filter technology to produce the delicious coffee we enjoy. How does it work exactly?
Espresso is produced by pushing hot water at high pressure through finely-ground coffee. The process is similar to that of making drip coffee. However, the pressure is the primary difference.
The Head of the Group
The name implies, the group head is where 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 various kinds of group heads, each with their own advantages and drawbacks. Some are focused on temperature stability, some on pre-infusion capabilities, while others are designed to control the lever. Some include a combination such as the E61. This is a popular choice among baristas since it provides multiple advantages in one package.
As you can see in the image above, the group head has many notches in which you can place your portafilter and twist it by hand to secure it. There is also a gasket made from rubber that is a part of the notches, which helps create an airtight seal when you insert your portafilter into the machine. The notches on the head allow for a precise positioning of the portafilter which is vital to ensure an even extraction.
The group head not only allows you to put in your portafilter easily however, it also keeps the same temperature. It does this by cycling hot water through the brew container and around the portafilter, ensuring that it's always at the correct temperature to extract. This is important, as even a few degrees can make the difference between a good and great espresso.
The Pump
The motorized pumps that are used in rotary espresso machines provide the nine atmospheric bars of pressure required for espresso extraction. This differs from manual piston machines that rely on a lever. The pressure is created by removing tap water from a reservoir, and pumping it through a heat exchanger before being shot through the ground coffee in the group head.
Pumps are typically less expensive than piston-driven machines, and tend to last longer, but both types of machines may get damaged through overuse and lack of cleaning. Pumps are also more complicated mechanically, which could increase prices of even most basic models.
Certain espresso machines utilize steam pressure instead of a pump to brew espresso. This can result in over-extraction because the boiler that makes steam also heats the water to boil. Additionally these machines typically have to restore their pressure between cups, which requires time and energy.
Many espresso machines make use of an rotary or a vibration pump. A vibration model utilizes the vibrating disk to create pressure, whereas the Rotary model pushes hot coffee through the ground at a high speed. Both machines can produce excellent espresso but rotary machines are more stable, quieter and less likely to fail.
The Boiler
The boiler is the component that heats water to the optimal temperature for extraction. The resulting steam reaches the portafilter containing ground espresso beans and gets funnelled down into the cup. During this process, the steam creates pressure to push through the coffee grounds. This results in a whipped-up top of the espresso. This is one of the hallmarks of a great espresso.
There are three types of espresso machines, each having different 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 employed one boiler to create steam and brew, however the pressure they were able to produce was very low - just two bars of atmospheric pressure at the most. This led to the coffee tasting bitter and burnt. This is why Milanese producers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.
The most common espresso maker is a semiautomatic machine with an electric pump. This is what people envision when they think of an espresso maker. Semi-automatic machines require you to grind and tamp the beans by yourself while the pump controls the flow of water and pressure. This is a great solution that combines human control with mechanized accuracy.
The Filter
Typically, espresso machines use a filter to separate out the grounds of coffee when they pass through the hot water. The filter is also a vital component of the machine's temp control, as it helps prevent overheating.
A filter also improves flavor because it allows for an extended flowering time. This lets the beans let their nuances out, and improves extraction.
It is important to keep in mind that even the finest filter can make a bad cup of coffee. The quality of the beans, and the extraction, are still crucial.
It's in this area that the magic happens. This is the reason why espresso tastes so good. The grouphead (also known as the brewhead) is where you place the portafilter, the thingy that you put the coffee grounds into, when making espresso.
Steam-driven espresso machines make use of hot water heated in an airtight vessel to create steam. The steam then pushes hot water through coffee grounds under high pressure. here These types of machines are typically less expensive and simpler to maintain than pump-driven models. They are however limited 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, espresso machines powered by a compressed air pump have become increasingly popular. They utilize an air compressor to force hot water into the grounds and are more portable than electric steam-driven machines.