How Does Machine Espresso Work?
Machine espresso uses precision pressure and mind-blowing filter technology to make the coffee we love. 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 Group Head
As the name suggests, the group head is where you put your portafilter in when brewing espresso. It is responsible for dispersing water into the portafilter before controlling the pressure of the resulting extraction. There are many different types of group heads each with distinct advantages and drawbacks. Some are focused on temperature stability, while others on pre-infusion capabilities, and still others are designed to control the lever. Some come with a range of features, like the E61 that is the most popular choice among baristas for its ability to offer multiple benefits in a single package.
As you can see in the above photo the group head comes with several notches where you put your portafilter, then twist it by hand to lock it in. A gasket made of rubber is placed inside the notches to help make a seal when you insert your portafilter. The notches allow for precise placement of the portafilter. This is crucial for a consistent extraction.
The group head does not just allow you to put in your portafilter easily but also maintains an even temperature. This is done by cycling hot water around the portafilter, and through the brew basin, ensuring that the temperature is always at the right level for extraction. This is important, as even a few degrees can be the difference between a excellent and great espresso.
The Pump
Unlike manual piston machines, which use a lever to pressurize water, rotating espresso machines rely upon motorized pumps to supply the nine atmospheric bars of pressure necessary to extract espresso. This pressure is generated by pumping water through a heat exchanger and then through the ground coffee.
Pumps are generally less expensive than piston-driven machines, and tend to last longer. However, both types of machine can get damaged through overuse and lack of cleaning. Pumps are also more complex mechanically, which can raise the price of even the most basic models.
Some espresso machines employ steam pressure instead of a pump to brew espresso. The drawback is that the boiler that produces steam also increases the temperature of water to the point of boiling which could lead to excessive extraction. In addition, these machines frequently have to restore their pressure between cups, which takes time and Professional Espresso Machine energy.
Many espresso machines make use of a rotary or vibration pump. A vibration model uses a vibrating disk to generate pressure, whereas the circular model pushes hot liquid through the ground at a fast speed. Both types of machine can produce an excellent espresso, but Rotary machines are quieter and more durable than vibration pumps.
The Boiler
The boiler is the element which heats the water to the ideal temperature to extract. The steam that is produced reaches the portafilter containing the ground espresso coffee, and gets funnelled down into the cup. During this process the steam is able to create enough pressure to push the grounds of the coffee through. This creates a crema on top of the espresso capsule machine. 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 use and the degree of heat that the coffee is. There are many ways to control the amount of brew, as well as the size of cup that can be made by the machine.
The first mini espresso maker machines were steam-type. The earliest espresso machines were steam-type machines. The coffee tasted bitter and burnt. The modern espresso machine was created by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.
The most commonly used espresso machine is a semiautomatic that has an electric pump. These are the images people have when they imagine an espresso machine. Semi-automatic machines require you to grind and tamp the beans yourself while the pump controls the water flow and pressure. This is an excellent compromise between human touch and mechanized consistency.
The Filter
Typically, espresso machines employ filters to separate the grounds of the coffee as they go through the hot water. The filter is also an essential element of the machine's temperature control, since it stops overheating.
Filters also aid in flavor as it allows for a longer flowering period. This allows beans to release their nuances and gives the chance for better extraction.
However, it is important to remember that even a top filter can result in a poor cup of coffee, since the quality of the beans and extraction is crucial.
It's in this area that the magic happens. This is what makes espresso taste so good. The grouphead (also called the brewhead) is where you place the portafilter, which is the thingy which you put the coffee grounds into, when making espresso capsule machine.
Steam-driven espresso machines use hot water heated in an airtight vessel to create steam. The steam then pushes hot water through the grounds of the coffee under pressure. These types of machines tend to be less expensive and simpler to maintain than pumps-driven models. However, they are not as efficient in their ability to produce the perfect conditions for brewing, because they operate at 1-1.5 bars of pressure. However, the perfect shot requires 9-10 bars.
In recent times, espresso machines powered by compressed air-pump are becoming increasingly popular. They use an air compressor to push the hot water through the grounds, and are far more portable than electric steam-driven machines.