15 Best Pinterest Boards To Pin On All Time About Machine Espresso
How Does Machine Espresso Work?
Machine espresso employs precise pressure and mind-blowing filter technology to create the perfect cup of coffee. But how exactly does it work?
In order to make espresso hot water is forced under high pressure through finely ground coffee. The process is similar to making drip coffee but the key difference is in the pressure.
The Group Head
As the name suggests, the group head is the place you place your portafilter while making espresso. It distributes water into the portafilter, and then regulates the pressure of extraction. There are various kinds of group head, each with their particular advantages and disadvantages. Some are designed for stability in temperature, while others are specifically designed to handle pre-infusion. Others are made to control the lever. Some have a combination, such as the E61. This is a preferred choice for baristas since it provides multiple advantages in a single package.
As you can see in the image above the group head is made up of several notches where you place your portafilter and then twist it by hand to lock it in. There is also a gasket made from rubber which is located inside the notches and helps create an airtight seal when you insert your portafilter into the machine. The notches permit precise placement of the portafilter. This is crucial to ensure an even extraction.
Aside from allowing you to easily insert your portafilter, the group head is also responsible to ensure that the temperature remains even. It does this by cycling hot water through the brew basket and around the portafilter, ensuring that it's always at the correct temperature for extraction. It is important to note that even a small deviation can make the difference between a good and great espresso.
The Pump
Motorized pumps in espresso machines that rotate provide the nine atmospheric bar pressure that is required for espresso extraction. This differs from manually operated piston machines that employ levers. The pressure builds up by removing tap water from a reservoir and pumping it through a heat exchanger prior to being pumped through the ground coffee inside the group head.
Pumps are typically less expensive and last for longer than piston-driven machines. However, both kinds of machines may degrade because of excessive use and insufficient cleaning. Pumps are also more complex mechanically, which could increase the price of even the simple models.
Some espresso machines eliminate the pump completely and instead use steam pressure to brew espresso. This could lead to over-extraction since the boiler that produces steam also causes the water to boil. In addition these machines are often required to rebuild their pressure between cups, which requires time and energy.
A large majority of espresso machines employ a rotary or vibration pump. A vibration model makes use of the vibrating disk to create pressure, whereas the rotary model pushes hot water through the ground at a fast speed. Both types of machines are capable of producing excellent espresso, however the rotary pumps are quieter, and more durable than vibration pumps.
The Boiler
The boiler is the component that heats water to an ideal temperature to extract. The resultant steam then reaches the portafilter that contains the ground espresso and is then pumped into the cup. During this process, steam creates pressure and pushes through the coffee grounds. This creates a layer crema that is then poured over. This is one of the hallmarks of a great espresso.
There are three types of espresso makers, and they differ in the kind of pump they use and the degree of heat that the brew is. There are a variety of ways in which the brew could be controlled and the size of the cup the machine can make.
coffee machine espresso were steam-types. They utilized one boiler to create both steam and brew however, the pressure they could produce was very low - just two bars of atmospheric pressure, at most. The coffee tasted bitter and burnt. The modern espresso machine was invented by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.
The most popular espresso machine is a semiautomatic with an electric pump. When people think of espresso machines, they think of these machines. If you have a semi-automatic machine you grind the beans and tamp them yourself but the pump is able to regulate the flow of water and pressure. This is a perfect solution that combines human control with mechanised reliability.
The Filter
Typically, espresso machines utilize a filter to separate out the grounds of coffee when they pass through the hot water. The filter is also an essential component of the temperature control system, since it helps prevent the machine from overheating.
It also enhances flavor, since a filter allows for a longer bloom time. This allows beans to release their flavors and provides an opportunity to improve extraction.
However, it is important to remember that even a high-quality filter can make a terrible cup of coffee, since the quality of the beans and extraction is still important.
It's here that the magic takes place. This is the reason why espresso tastes so good. The grouphead (also called the brewhead) is where you put the portafilter - the thingy used to place the coffee grounds into, when making espresso.
Steam-driven espresso machines use hot water that is heated inside an airtight container to make steam. The steam then pushes hot water into the grounds of coffee at high pressure. These machines are less expensive and easier for the user to maintain than pumps-driven models. They are however limited for creating 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 been gaining popularity. They utilize an air compressor to force hot water through the ground, and are more mobile than steam-driven electric espresso machines.