15 Top Pinterest Boards From All Time About Machine Espresso
How Does Machine Espresso Work?
The machine espresso is made using precise pressure and filtering technology that is amazing to create the coffee you enjoy. What exactly is it that makes it work?
Espresso is made by forcing hot water at high pressure through finely ground coffee. The process is similar to making drip coffee but the major difference is in the pressure.
The Head of the Group
The group head is the portafilter that you place in the espresso maker when making it. It is responsible for dispersing water into the portafilter, and controlling the pressure of the extraction. There are many different types of group heads each with distinct advantages and drawbacks. check here on temperature stability, some on pre-infusion options, and others are designed to control the lever. Some come with a combination of both, like the E61. This is a preferred choice for baristas since it provides multiple advantages in a single package.
As you can see from the photo above, the group head is fitted with several notches. You can place your portafilter inside these notches, and then turn the head around to secure it. There is also a rubber gasket that resides inside the notches and helps create the seal when you insert your portafilter into the machine. The notches permit precise placement of the portafilter. This is vital for an accurate extraction.
Apart from allowing you easily place your portafilter in, the group head is also responsible to ensure that the temperature remains even. It does this by circulating hot water through the brew basket and around the portafilter to ensure that it is always at the right temperature to extract. It is important to realize that even a small differences can make the distinction between a good and excellent espresso.
The Pump
The motorized pumps that are used in espresso machines that rotate provide the nine atmospheric bar pressure that is required for espresso extraction. This is different from manual piston machines that rely on levers. The pressure is created by pumping water through a heat exchanger and then through the ground coffee.
Pumps tend to be less expensive than piston-driven machines, and they tend to last longer, but both types of machines may degrade with overuse and insufficient cleaning. Pumps are also more complex mechanically, which can raise the cost of even the simple models.
Some espresso machines employ steam pressure instead of a pump for brewing espresso. This could lead to over-extraction since the boiler that makes steam also heats the water to boil. The machines also need to constantly rebuild their pressure between cups. This takes energy and time.
A majority of espresso machines use a vibration or rotary pump, with a vibration model that uses a vibrating disc to create pressure, and an rotary model that pushes hot water through the grounds at high speed. Both types of machine can make excellent espresso, but rotary machines are quieter and more durable than vibration pumps.
The Boiler
The boiler is the part that heats water to an optimal temperature for extraction. The resulting steam is then transferred to the portafilter containing the ground espresso coffee and gets funnelled down into the cup. In this process, the steam causes pressure to push through the grounds of the coffee. This results in a whipped-up top of the espresso. This is the hallmark of a great espresso.
There are three types of espresso machines, each with a different type of pump and brew temperature. There are different ways that the brew can be controlled, as well as the size of the cup that the machine can produce.
The earliest espresso machines were steam-based. They used a single boiler to make both brew and steam, however the pressure they were able to create was minimal - two bars of atmospheric pressure, at most. This resulted in the coffee tasting burnt and bitter. This is why Milanese producers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.
The most well-known espresso machine is a semiautomatic that has an electric pump. These are the images people have when they think of an espresso maker. Semi-automatic machines require you to grind and tamp the beans on your own, but the pump regulates the flow of water and pressure. This is an excellent solution that combines human control with mechanized reliability.
The Filter
Espresso machines typically have filters that separate the coffee grounds from the hot water. The filter is also a crucial component of the temperature control system, as it keeps the machine from overheating.
Filters also aid in flavor, as it permits a longer flowering phase. This allows the beans to release their flavors, and allows for better extraction.
It is important to keep in mind that even the finest filter could result in a poor cup of coffee. The quality of the beans, as well as the extraction, remain vital.
It's in this area that the magic occurs. This is the reason why espresso tastes so good. The grouphead (also called the brewhead) is where you put the portafilter - the thingy that you use to put the coffee grounds into, when making espresso.
In the steam-driven espresso machine hot water is heated in an airtight container to create steam, which then pushes the hot water through the grounds at a high pressure. These machines are less expensive and are easier for the user 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-pump-driven espresso machines have become more popular. They utilize an air compressor to force hot water into the grounds and are significantly more portable than steam-driven electric machines.