The 9 Things Your Parents Teach You About Machine Espresso
How Does Machine Espresso Work?
Machine espresso utilizes precise pressure and mind-blowing filter technology to create the perfect cup of coffee. How does it work exactly?
To make espresso hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee espresso machines. However the pressure is the main difference.
The Head of the Group
The group head is the portafilter that is inserted when you are making espresso. It is responsible for dispersing the water into the portafilter, and controlling the pressure that results from the extraction. There are many different kinds of group head, each with their particular advantages and disadvantages. Some are focused on temperature stability, whereas others on pre-infusion options, and others are designed to control the lever. Some include a combination such as the E61. This is a very popular choice for baristas because it offers multiple benefits in one package.
As you can see in the photo above, the group head has several notches to place your portafilter and twist it manually to lock it in. There is also a gasket made of rubber in the notches and helps create an airtight seal after inserting your portafilter into the machine. The notches allow for an exact placement of the portafilter. This is crucial for an even extraction.
In addition to allowing you easily insert your portafilter, the group head is also responsible for maintaining an even temperature. This is achieved by cycling hot water around the portafilter and through the brew basin, ensuring the temperature is always right for extraction. This is important because even a few degrees can make the difference between a good and excellent espresso.
The Pump
Unlike manual piston machines, which rely on a lever that pressurize water, the rotary espresso machines use motorized pumps to supply the nine atmospheric bars of pressure necessary for espresso extraction. This pressure is generated by pumping water through a heat-exchanger and then through the ground coffee.
Pumps tend to be less expensive and last for longer than piston-driven machines. However, both types of machines can degrade due to excessive use and inadequate cleaning. Pumps are also more complex mechanically, which can raise the price of even the simpler models.
Some espresso machines employ steam pressure instead of a pump to make espresso. The disadvantage of this is that the boiler that produces steam also increases the temperature of the water bean to cup espresso machine boiling which could lead to over-extraction. In addition the machines often have to rebuild their pressure between cups, which takes time and energy.
A majority of espresso machines use the rotary or vibration pump, which is a vibration model that uses a vibrating disc that generates the pressure and a rotary model pushing hot water through the grounds under high speed. Both machines produce great best espresso machine under 500 however rotary machines tend to be more quiet, durable and less likely to break down.
The Boiler
The boiler is the one that heats the water to the ideal temperature for extraction. The steam that is created will eventually reach the portafilter, which is the container that holds the espresso coffee grounds. It is then pumped into the cup. The steam is able to create enough pressure to push the grounds of coffee through. This creates a foam on top espresso machines of the espresso. This is the hallmark of a great espresso.
There are three kinds of espresso makers, and they differ in the type of pump they use and how hot the brew is. There are many ways to control the brew as well as the size of cup that can be made by the machine.
The first espresso machines were steam-types. They had one boiler to create both brew and steam, however, the pressure they could create was minimal - two bars of atmospheric pressure at most. The coffee tasted bitter and burned. This is why Milanese producers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.
The most commonly used espresso maker is a semiautomatic machine that has an electric pump. When people think of espresso machines, they picture these machines. Semi-automatic machines require you to grind and tamp the beans by yourself however the pump controls the flow of water and pressure. This is an excellent compromise between human touch and the mechanized quality.
The Filter
Espresso machines usually have a filter that separates the grounds of coffee from hot water. The filter is also a vital component of the machine's temp control, as it helps prevent overheating.
A filter can also help with flavor because it allows for an extended flowering time. This allows the beans to let their nuances out and provides an opportunity for a better extraction.
However it is crucial to remember that even a great filter can result in a poor cup of coffee, since the quality of the beans and extraction are crucial.
It's in this area that the magic happens. 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 ground coffee in) is located when you're making espresso.
In a steam-driven espresso machine, hot water is heated in an airtight tank to produce steam, which then pushes the hot water through the grounds with high pressure. These kinds of machines are generally less expensive and easier to maintain than pump-driven models. However, they are limited in their ability to produce the perfect brewing conditions since they are only operating at 1-1.5 bars 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 the hot water through the grounds and are more portable than steam-driven electric machines.