How Does Machine Espresso Work?
The machine espresso makes use of precise pressure, as well as a filtering system that is awe-inspiring to make the coffee you enjoy. How exactly does it work?
In order to make espresso hot water is pushed under 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 where you place your portafilter when making espresso. It is responsible for dispersing water into the portafilter before controlling the pressure of the extraction. There are several different types of group head each with its particular advantages and drawbacks. Some are specifically designed for stability of temperature while others are built to handle pre-infusion. Others are made to control the lever. Some come with a range of features, such as the E61 one, which is the most popular choice among baristas due to its ability to provide multiple benefits in one package.
As you can see in the photo above the group head has a number of notches. You can place your portafilter into these notches and twist the head to lock it. A gasket made of rubber is positioned within the notches to create a seal as you insert your portafilter. The notches on the head allow for an exact location of the portafilter which is necessary for an even extraction.
The group head not only allows you to insert your portafilter easily however it also keeps 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 tiny difference can make the difference between a decent espresso machine and a excellent espresso.
The Pump
In contrast to piston machines that are manually operated, which rely on a lever that pressurize water, rotary cheap espresso machine machines rely on motorized pumps to supply the nine atmospheric bars of pressure that are required for espresso extraction. This pressure is generated by pumping water through a heat-exchanger and then through the ground coffee.
Pumps tend to be cheaper than piston-driven machines, and they tend to last longer, although both types of machines may get damaged through overuse and lack of cleaning. Pumps are also more complex mechanically, and can add to the price of even the most basic models.
Some espresso machines do away with the pump completely and instead use steam pressure to brew espresso. This can result in over-extraction because the boiler that makes steam also warms the water to boil. They also have to continuously rebuild their pressure between cups. This takes energy and time.
A large majority of espresso machines employ an rotary or a vibration pump. A vibration model employs a vibrating disk to generate pressure, while a rotary model pushes hot water through the ground at a high speed. Both machines can make great espresso, however rotary machines are more stable, quieter and less likely to break down.
The Boiler
The boiler is the part which heats the water to the optimal temperature for extraction. The resultant steam then reaches the portafilter which holds the ground espresso coffee machine coffee, and is then funneled down into the cup. The steam is able to create enough pressure to push the coffee grounds through. This produces a layer of crema on top. This is one of the hallmarks of a good espresso.
There are three types of travel espresso maker (Todaybookmarks.Com) machines, each having different types of pumps and brew temperature. There are a variety of ways to control the strength of the brew and the size of the cup that can be made by the machine.
The first espresso machines were steam-types. They employed one boiler to make steam and brew, but the pressure they could produce was very low – just two bars of atmospheric pressure, at most. This led to the coffee tasting bitter and burnt. This is why Milanese makers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso makers machine.
The most common espresso maker is a semi-automatic device that has an electric pump. When people think of espresso machines, they envision these machines. Semi-automatic machines require you to grind and tamp your beans yourself The pump, however, regulates the water flow and pressure. This is an excellent compromise between human touch and mechanized consistency.
The Filter
Espresso machines usually have a filter that separates the grounds of coffee from hot water. The filter is also an essential component of the machine’s temp control, since it helps to prevent overheating.
It also enhances flavor, as it lets you enjoy a longer bloom phase. This lets the beans release their nuances, and improves extraction.
However, it is important to keep in mind that even a great filter can result in a poor cup of coffee, as the quality of the beans and extraction is important.
It’s here that the magic happens. This is what makes espresso taste so delicious. The grouphead (also known as the brewhead) is where you place the portafilter, the thingy that you use to put the coffee grounds in, when making espresso.
In an espresso machine that is driven by steam, hot water is heated in an airtight container to create steam, which is then pushed through the grounds with high pressure. These kinds of machines are typically less expensive and simpler to maintain than pump-driven models. However, they are not as efficient in their ability to produce the perfect conditions for brewing, since they operate 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 use an air compressor to force the hot water through the grounds and are much more portable than steam-driven electric machines.