14 Cartoons About Machine Espresso That'll Brighten Your Day
How Does Machine Espresso Work?
The machine espresso uses precise pressure and filter technology that is awe-inspiring to create the coffee you enjoy. What exactly is it?
In similar site to make espresso hot water is pushed under pressure through finely ground coffee. The process is similar to that of making drip coffee. However, it is the pressure that makes the main difference.
The Group Head
The name implies, the group head is the place you place your portafilter when making espresso. It disperses water in the portafilter, and then regulates the pressure of the extraction. There are a variety of group heads each with its own advantages and disadvantages. Some focus on temperature stability, some on pre-infusion features, and others are designed to control the lever. There are also some that contain a variety of features, such as the E61, which is considered to be the most popular among baristas because of its ability to provide multiple benefits in one package.
As you can see in the photo above the group head comes with several notches to place your portafilter and then twist it by hand to lock it in. There is also a gasket made from rubber that resides inside the notches to help create a seal when you insert your portafilter into the machine. The notches permit precise placement of the portafilter. This is essential for an efficient extraction.
The group head not only lets you to insert your portafilter easily, but it also maintains the temperature at a constant level. It does this by cycling hot water through the brew container and around the portafilter, ensuring that it is always at the right temperature to extract. It is important to remember that even a few degree difference can make the difference between a good and excellent espresso.
The Pump
The motorized pumps in rotary espresso machines supply the nine atmospheric bars of pressure required to extract espresso. This differs from manual piston machines that rely on a lever. The pressure is created by drawing tap water from a reservoir and pumping it through a heat exchanger prior to being pumped through the ground coffee in the group head.
Pumps are generally less expensive than piston-driven models, and they tend to last longer, however both types of machines could get damaged through overuse and lack of cleaning. Pumps are also more complicated mechanically, which can raise the cost of even most basic models.
Some espresso machines employ steam pressure instead of a pump for brewing espresso. The downside is that the same boiler that produces steam also raises the temperature of water to the point of boiling which could lead to excessive extraction. Additionally these machines typically have to restore their pressure between cups, which requires time and energy.
A majority of espresso machines use the rotary or vibration pump, with a vibrating model using a vibrating disc to create the pressure, and an rotary model that pushes hot water through the grounds at high speed. Both models are capable of producing excellent espresso, however Rotary machines are quieter and more durable than vibration pumps.
The Boiler
The boiler is what is used to heat the water to the ideal temperature for extraction. The steam created is then directed to the portafilter, which contains the espresso coffee grounds. It is then funneled into the cup. The steam creates pressure to push through the coffee grounds. This creates a foam on the top of the espresso. This is the hallmark of a good 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 espresso is. There are different ways that the brew can be controlled and the size of the cup that the machine can make.
The first espresso machines were steam-type. They had only one boiler to make both steam and brew however, the pressure they could create was minimal - two bars of atmospheric pressure maximum. The coffee tasted bitter and burned. The modern espresso machine was developed by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.
The most popular espresso machine is a semiautomatic that has an electric pump. When people think of espresso machines, they envision these machines. Semi-automatic machines require you to grind and tamp the beans on your own however the pump controls the water flow and pressure. This is an excellent combination of human control and mechanised consistency.
The Filter
Typically, espresso machines employ filters to separate the grounds of coffee as they move through the hot water. The filter is also an essential element of the machine's temperature control, since it helps to prevent overheating.
A filter also improves flavor, as it permits the beans to flower for a longer period of time. This allows the beans to release their flavors, and also allows for better extraction.
It is important to remember that even the most efficient filter can result in a bad cup of coffee. The quality of the beans, and the extraction, remain vital.
This is where the magic happens, it's the thing that makes espresso taste great. The grouphead (also known as the brewhead) is where you put the portafilter - the thingy that you use to put 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 through the grounds of coffee under high pressure. These types of machines are usually less expensive and simpler to maintain than pump-driven models. They are however limited for creating the ideal conditions for brewing, as they 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 compressor have become increasingly popular. They utilize an air compressor to force hot water through the grounds and are significantly more portable than steam-driven electric machines.