How The 10 Worst Machine Espresso Mistakes Of All Time Could Have Been Prevented
How The 10 Worst Machine Espresso Mistakes Of All Time Could Have Been Prevented
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How Does Machine Espresso Work?
Machine espresso utilizes precise pressure and mind-blowing filter technology to make the coffee we love. What exactly is it?
To make espresso, hot water is forced under high 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
As the name implies, the group head is the place you put your portafilter in when making espresso. It is responsible for dispersing the water into the portafilter before controlling the pressure that results from the extraction. There are numerous kinds of group heads each with distinct advantages and drawbacks. Some focus on temperature stability, while others on pre-infusion options, and others are designed to control the lever. Some have a combination, such as the E61. This is a preferred choice for baristas because it offers multiple advantages in a single package.
As you can see in the photo above, the group head has several notches to place your portafilter and twist it with your hands to secure it. A gasket made of rubber is placed inside the notches to help create a seal while you insert your portafilter. The notches on the head permit an exact position of the portafilter which is vital for an efficient extraction.
The group head not only allows you to insert your portafilter easily but also maintains a constant temperature. This is accomplished by cycling hot water around the portafilter, and through the brew-basket to ensure that the temperature is at the right level to extract the coffee. This is important because even a few degrees can be the difference between a good and excellent espresso.
The Pump
In contrast to piston machines that are manually operated, which use a lever to pressurize water, the rotary espresso machines use motorized pumps that provide the nine atmospheric bars of pressure that are required to extract espresso. 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 could get damaged through overuse and lack of cleaning. They also create mechanical complexity, which can result in an expensive price for even the most basic models.
Certain espresso machines eliminate the pump entirely and utilize steam pressure to make espresso. This can lead to over-extraction as the boiler that makes steam also heats the water until it comes to a boil. The machines also need to continuously rebuild their pressure between cups. This takes energy and time.
Many espresso machines make use of a rotary or vibration pump. A vibration model employs an oscillating disk to create pressure, whereas a Rotary model pushes hot coffee through the ground at a high speed. Both types of machines can make a great espresso, however Rotary machines are quieter and more durable than vibration pumps.
The Boiler
The boiler heats the water to the perfect temperature for extraction. The steam created will eventually reach the portafilter, which contains the espresso coffee grounds. It is then pumped into the cup. The steam causes enough pressure to push the grounds of the coffee through. This results in a whipped-up top of the espresso. This is a sign of a good espresso.
There are three distinct types of espresso machines, each with different pumps and the temperature of the brew. There are various ways to control the amount of brew, as well as the size of the cup that can be made by the machine.
The first espresso machines were steam-based. They utilized one boiler to make both brew and steam, however the pressure they were able to generate was low - only two bars of atmospheric pressure at the most. This resulted in the coffee tasting bitter and burnt. The modern espresso machine was invented by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.
The most common espresso machine is a semiautomatic that has an electric pump. When people think of espresso machines, they imagine these machines. Semi-automatic machines require you to grind and tamp the beans yourself, click here but the pump regulates the water flow and pressure. This is a fantastic combination of human control and mechanized accuracy.
The Filter
Typically, espresso machines use filters to separate the grounds of coffee as they move through the hot water. The filter is also an essential 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 period. This allows beans to release their flavors and provides an opportunity for a better extraction.
However, it is important to remember that even a high-quality filter can produce a bad cup of coffee, since the quality of the beans and extraction is essential.
It's in this area that the magic takes place. This is the reason why espresso tastes so delicious. The grouphead, often referred to as the brewhead, is where the portafilter (the thingy you put the coffee grounds into) sits when you're 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 under high pressure. These types of machines are usually less expensive and easier 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-driven espresso machines have been gaining popularity. They utilize an air compressor to push hot water into the grounds and are much more portable than steam-driven electric machines.