10 Quick Tips About Machine Espresso
How Does Machine Espresso Work?
The machine espresso uses precision pressure, and a filtering system that is awe-inspiring to make the coffee you enjoy. But how exactly does it work?
To make an espresso hot water is forced under high pressure through finely ground coffee. The process is similar to making drip coffee however the main difference lies in the pressure.
The Group Head
As the name suggests, the group head is the place you put your portafilter in when making espresso. It disperses water in the portafilter, and then regulates the pressure of extraction. There are various kinds of group head, each with their distinct advantages and drawbacks. Some are designed to provide stability in temperature, while others are built to handle pre-infusion. Others are made to control the lever. There are even some that include a mix of features, such as the E61 that is the standard choice for many baristas because of its ability to offer multiple perks in one package.
As you can see in the above photo, the group head is fitted with several notches. It is possible to place your portafilter inside these notches, and then twist the head to secure it. A gasket made of rubber is placed within the notches to create a seal as you insert your portafilter. The notches permit an exact placement of the portafilter. This is essential for a consistent extraction.
In addition to allowing you to easily insert your portafilter, the group head is responsible for maintaining an even temperature. It does this by circulating hot water through the brew pan and around the portafilter, making sure that it's always at the right temperature to extract. This is important because even a small difference in temperature can make the difference between good and excellent espresso.
The Pump
The motorized pumps used in rotary espresso machines provide the nine atmospheric bar pressure needed to extract espresso. This is different from manual piston machines that use a lever. The pressure is built 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 types of machines can deteriorate because of excessive use and poor cleaning. Pumps are also more complex mechanically, which could increase the cost of even the most basic models.
Certain espresso machines eliminate the pump entirely and utilize steam pressure to make espresso. The disadvantage of this is that the boiler that produces steam also increases the temperature of water to boiling and can result in over-extraction. The machines must also continually rebuild their pressure between cups. This takes energy and time.
Many espresso machines utilize a vibration or rotary pump, which is a vibration model that uses a vibrating disc to create pressure, and rotating models that push hot water through the grounds at high speed. Both machines can make great espresso however rotary machines tend to be quieter, more durable and less likely to fail.
The Boiler
The boiler is the element that heats the water to the ideal temperature for extraction. The steam created reaches the portafilter, which is the container that holds the espresso coffee grounds. It is then poured 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. This is a sign of a good espresso.
There are three types of espresso makers. They differ in the kind of pump they use and how hot the espresso is. There are different ways in which the brew could be controlled and the size of the cup the maker can create.
The first espresso machines were steam type. They had a single boiler to make both steam and brew however the pressure they were able to create was minimal - two bars of atmospheric pressure maximum. The coffee tasted bitter and burnt. The modern espresso machine was created by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.
The most common espresso maker is a semi-automatic one with an electric pump. These are what people imagine when they think of an espresso maker. If you have a semi-automatic machine you must grind the beans and then tamp them by hand. The pump provides regulated water flow and pressure. This is an excellent compromise between human control and mechanised consistency.
The Filter
Typically, espresso machines utilize a filter to separate out the grounds of coffee as they move through the hot water. The filter is also a vital part of the temperature control system, because it stops the machine from overheating.
home espresso machine improves flavor, as a filter allows for a longer bloom time. This lets the beans release their flavor and allows for a better extraction.
It is important to keep in mind that even the best filter can make a bad cup of coffee. The quality of the beans as well as the extraction, are still crucial.
It's here that the magic occurs. This is the reason why espresso tastes so delicious. The grouphead (also known as the brewhead) is where you place the portafilter, the thingy used to place the grounds of coffee into when making espresso.
Steam-driven espresso machines use hot water that is heated inside an airtight container to create steam. The steam then pushes hot water into the grounds of the coffee under pressure. These kinds of machines are generally cheaper and easier to maintain than pump-driven models. They are however limited for creating the ideal conditions for brewing since they only operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.
In recent years, espresso machines powered by a compressed air pump have become increasingly popular. They use an air-compressor to push hot water across the ground. They are also more mobile than electric steam-driven espresso machines.