10 Tell-Tale Signals You Need To Look For A New Machine Espresso
10 Tell-Tale Signals You Need To Look For A New Machine Espresso
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How Does Machine Espresso Work?
Machine espresso utilizes precise pressure and mind-blowing filter technology to create the delicious coffee we enjoy. How exactly does it work?
Espresso is created by forcing hot water under pressure through finely ground coffee. The process is similar to 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 water in the portafilter, and regulates the pressure during the extraction. There are many different types of group heads each with their own advantages and disadvantages. Some are focused on temperature stability, whereas others on pre-infusion options, and others are designed to control the lever. Some are a combination, like the E61. This is a very popular choice for baristas because it offers multiple benefits in a single package.
As you can see in the photo above, the group head has a number of notches. It is possible to place your portafilter in these notches and then turn the head around to secure it. There is also a gasket made from rubber that is a part of the notches and helps to create a seal when you insert your portafilter into the machine. The notches permit precise placement of the portafilter. This is essential for an accurate extraction.
The group head not only lets the portafilter to be inserted easily however it also keeps a constant temperature. It does this by circulating hot water through the brew pan and around the portafilter, making sure that it's always at the right temperature for extraction. It is important to realize that even a slight differences can make the distinction between a decent and a excellent espresso.
The Pump
The motorized pumps in espresso machines rotary provide nine atmospheric bar pressure required to extract espresso. This differs from manual piston machines that use a lever. The pressure builds up by drawing tap water from a reservoir, and pumping it through a heat exchanger prior being pumped through the ground coffee in the group head.
Pumps are typically less expensive and last for longer than piston-driven machines. However, both kinds of machines can degrade due to excessive use and poor cleaning. Pumps are also more complex mechanically, which could increase the cost of even the most basic models.
Some espresso machines do away with the pump completely and instead employ steam pressure to create espresso. The drawback is that the same boiler that produces steam also increases the temperature of the water to the point of boiling which can cause excessive extraction. Additionally these machines typically have to rebuild their pressure between cups, which requires time and energy.
A large majority of espresso machines employ an rotary or a vibration pump. A vibration model uses a rotating disk to generate pressure, whereas a rotating model pushes hot water through the ground at a fast speed. Both models can make a great coffee for espresso machine espresso, however the rotary pumps are quieter, and more durable than vibration pumps.
The Boiler
The boiler is what will heat the water to the perfect temperature for extraction. The steam produced reaches the portafilter, which contains the espresso coffee grounds. It is then pumped into the cup. During this process the steam causes enough pressure to push the grounds of coffee through. This creates a crema on the top of the espresso. This is one of the hallmarks of a good espresso.
There are three kinds of espresso makers. They differ in the type of pump they employ and how hot the coffee is. There are various ways to control the brew as well as the size of the cup that can be made by the machine.
The first espresso machines were steam-type. They used one boiler to create both steam and brew however the pressure they were able to produce was not very high - two bars of atmospheric pressure maximum. This led to the coffee tasting burnt and bitter. This is the reason Milanese makers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.
The most well-known espresso maker is a semi-automatic machine that has an electric pump. This is what people envision when they think of an espresso machine. Semi-automatic machines require you to grind and tamp the beans on your own while the pump controls the water flow and pressure. This is a great combination of human control and mechanised consistency.
The Filter
Espresso machines typically use filters that separate the grounds of the coffee from the hot water. The filter is also an essential part of the temperature control system as it keeps the machine from overheating.
It also aids in flavor as a filter lets you enjoy a longer bloom phase. This allows the beans to let their nuances out, and improves extraction.
However, it is important to keep in mind that even a high-quality filter could result in a bad cup of coffee, since the quality of the beans and extraction is important.
It's in this area that the magic occurs. This is what makes espresso taste so good. The grouphead (also known as the brewhead) is where you put the portafilter - the thingy which you put the coffee grounds into, when making espresso.
In an espresso machine that is driven by steam, hot water is heated in an airtight tank to create steam, which then pushes the hot water through the grounds at high pressure. These machines are cheaper and easier for the user to maintain than pumps-driven models. They are however limited in their ability to create the ideal brewing conditions as they only operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.
In recent years, espresso machines driven by compressed air-pump have become increasingly popular. They use an air-compressor to force hot water into the ground and are much more mobile than steam-driven electric espresso machines.