Are You Getting Tired Of Machine Espresso? 10 Inspirational Sources That Will Revive Your Passion
How Does Machine Espresso Work?
Machine espresso makes use of precise pressure and amazing filter technology to make the delicious coffee we enjoy. But how exactly does it work?
Espresso is made by pushing hot water under high pressure through finely-ground coffee. best espresso machine is similar to making drip coffee. However the pressure is the major 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 the water into the portafilter, and controlling the pressure that results from the extraction. There are numerous kinds of group heads each with their own advantages and drawbacks. Some focus on temperature stability, others on pre-infusion capabilities, and still others are designed to control the lever. Some are a combination, like the E61. This is a popular choice among baristas since it provides multiple benefits in one package.
As you can see in the above photo, the group head has several notches where you place your portafilter before twisting it with your hands to lock it in. There is also a rubber gasket that resides inside the notches, which helps create a seal when you insert your portafilter into the machine. The notches allow for the precise placement of the portafilter. This is essential for an accurate extraction.
In addition to allowing you easily insert your portafilter, the group head is responsible to ensure that the temperature remains even. This is done by cycling hot water around the portafilter and through the brew-basket to ensure that the temperature is always at the right level to extract the coffee. This is crucial, since even a few degrees can make the difference between good and excellent espresso.
The Pump
The motorized pumps used in espresso machines rotary provide nine atmospheric bar pressure that is required to extract espresso. This is different from manually operated piston machines that employ levers. The pressure builds up by drawing tap water from a reservoir and pumping it through a heat exchanger prior it is shot through the ground coffee in the group head.
Pumps are typically less expensive than piston-driven machines, and tend to last longer. However, both types of machine can become damaged due to excessive use and poor cleaning. Pumps are also more complex mechanically, which can increase the cost of even simpler models.
Certain espresso machines can eliminate the pump completely and make use of steam pressure to make espresso. The disadvantage of this is that the same boiler that produces steam also raises the temperature of the water to boiling which can cause over-extraction. Additionally, these machines frequently have to rebuild their pressure between cups, which takes time and energy.
Many espresso machines make use of a vibration or rotary pump, which is a vibration model that uses a vibrating disc that generates the pressure and the rotary model pushing hot water through the grounds under high speed. Both machines can produce excellent espresso, however rotary machines are more stable, quieter and less likely to break.
The Boiler
The boiler is the component that heats the water to the ideal temperature to extract. The steam that is created reaches the portafilter, which is the container that holds the espresso coffee grounds. The steam is then channeled into the cup. During this process, the steam creates pressure and pushes through the grounds of the coffee. This results in a whipped-up the top of the espresso. This is a sign of a good espresso.
There are three distinct types of espresso machines, each with a different type of pump and brew temperature. There are also different ways in which the brew could be controlled as well as the dimensions of the cup the machine can produce.
The earliest espresso machines were steam types. They utilized only one boiler to make both steam and brew, however, the pressure they could produce was not very high - two bars of atmospheric pressure at most. This resulted in the coffee tasting burnt and bitter. The modern espresso machine was created by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.
The most commonly used espresso maker is a semi-automatic machine that has an electric pump. This is what people envision when they think of an espresso machine. With a semi-automatic machine you need to grind the beans and then tamp them yourself but the pump regulates the flow of water and pressure. This is a great compromise between the human touch and the mechanized accuracy.
The Filter
Typically, espresso machines utilize filters to separate the grounds of coffee as they move through the hot water. The filter is also an essential component of the machine's temp control, since it helps to prevent overheating.
It also aids in flavor, as a filter can allow for a longer bloom phase. This allows the beans to release their flavors, and also allows for 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 is still vital.
It's in this area that the magic happens. This is the reason why espresso tastes so delicious. The grouphead (also called the brewhead) is where you put the portafilter, the thingy that you use to put the coffee grounds into, while making espresso.
In the steam-driven espresso machine hot water is heated in an airtight tank to create steam. Steam then pushes the hot water through the grounds at a high pressure. These machines are less expensive and easier to maintain than pumps-driven models. However, they are limited in their capacity to create the ideal brewing conditions, as they only operate at 1-1.5 bars of pressure. However, the perfect shot requires 9-10 bar.
In recent years, compressed air-driven espresso machines have become more popular. They utilize an air compressor to force hot water into the ground and are much more mobile than steam-driven electric espresso machines.