20 Questions You Must Always Have To Ask About Machine Espresso Before Purchasing It
20 Questions You Must Always Have To Ask About Machine Espresso Before Purchasing It
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How Does Machine Espresso Work?
Machine espresso uses precision pressure and amazing filter technology to make the delicious coffee we enjoy. What exactly does it work?
To make an 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 implies, the group head is the place you place your portafilter while making espresso. It is responsible for dispersing water into the portafilter, and controlling the pressure of the resulting extraction. There are many different kinds of group head each with its unique advantages and drawbacks. Some are designed to provide temperature stability while others are built to handle pre-infusion. Others are made to control the lever. Some are a combination, such as the E61. This is a very popular choice for baristas since it provides multiple benefits in a single package.
As you can see in the photo above The group head features several notches where you place your portafilter before twisting it by hand to secure it. There is also a gasket of rubber that resides inside the notches and helps create a seal when you insert your portafilter into the machine. The notches on the head allow for an exact positioning of the portafilter which is crucial to ensure a consistent extraction.
The group head not only lets you to place your portafilter easily, but it also maintains the same 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 to extract. This is crucial, since even a few degrees can be the difference between a good and great espresso.
The Pump
Unlike manual piston machines, which rely on a lever that pressurize water, rotary espresso machines rely on motorized pumps to supply the nine atmospheric bars of pressure needed for espresso extraction. The pressure is created by pumping water through a heat exchanger and then through the ground coffee.
Pumps are typically less expensive and last for longer than piston-driven machines. However, both kinds of machines can deteriorate due to excessive use and inadequate cleaning. They also add mechanical complexity and can lead to an expensive price for even the most basic models.
Some espresso machines eliminate the pump completely and instead make use of steam pressure to make espresso. This can lead to over-extraction as the boiler that makes steam also warms the water to boil. In addition these machines are often required to restore their pressure between cups, which requires time and energy.
A large majority of espresso machines employ an rotary or a vibration pump. A vibration model employs a vibrating disk to generate pressure, whereas the Rotary model pushes hot coffee through the ground at a fast speed. Both types of machines can make excellent espresso, however rotary machines are quieter and more durable than vibration pumps.
The Boiler
The boiler is what heats the water to a temperature that is ideal to extract. The steam produced is then directed to 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 to push through the coffee grounds. This results in a layer crema that is then poured over. This is a sign of a good espresso.
There are three kinds of espresso machines, each having different types of pumps and brew temperature. There are various ways in which the brew could be controlled as well as the size of the cup the machine can make.
The earliest espresso machines were steam-based. The first espresso machines were steam types. The coffee tasted bitter and burnt. The modern espresso machine was designed by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.
The most commonly used espresso machine is a semiautomatic one with an electric pump. This is what people envision when they imagine an espresso machine. Semi-automatic machines require you to grind and tamp the beans yourself, but the pump regulates the water flow and pressure. This is an excellent combination of human control and mechanized accuracy.
The Filter
Espresso machines usually use a filter that separates the grounds of the coffee from hot water. The filter is also a crucial component of the temperature control system since it helps prevent the machine from overheating.
It also improves flavor, since a filter lets you enjoy a longer bloom phase. This helps the beans to release their flavors and provides an opportunity to improve extraction.
It is important to keep in mind that even the finest filter can produce a bad cup of coffee. The quality of the beans and the extraction, remain crucial.
This is where the magic happens, and it's what makes espresso taste great. The grouphead (also called the brewhead) is where you place the portafilter, which is the thingy that you put the grounds of coffee into when making espresso.
In the steam-driven espresso machine hot water is heated in an airtight tank to produce steam, which is then pushed through the grounds with high check here pressure. These types of machines are typically less expensive and easier to maintain than pump-driven models. They are however limited in their ability for creating the ideal conditions for brewing, as they operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.
In recent years, espresso machines driven by compressed air-pump are becoming increasingly popular. They make use of an air compressor to force hot water through the ground, and are more mobile than electric steam-driven espresso machines.