How Does Machine Espresso Work?
(Image: https://cdn.freshstore.cloud/offer/images/778/10700/swan-retro-pump-espresso-coffee-machine-grey-15-bars-of-pressure-milk-frother-1-2l-tank-sk22110grn-10700.jpg)Machine espresso utilizes precise pressure and amazing filter technology to make the delicious coffee we enjoy. 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. However, the pressure is the major difference.
The Head of the Group
The group head is the portafilter is inserted when you are making espresso. It disperses water in the portafilter and controls the pressure of the extraction. There are a variety of types of group head, each with their unique advantages and drawbacks. Some focus on temperature stability, some on pre-infusion options, and others are designed to control the lever. There are some that contain a variety of features, like the E61, which is considered the most popular choice among baristas due to its ability to offer multiple benefits in a single package.
As you can see in the above image, the group head has several notches where you put your portafilter, then twist it with your hands to secure it. A gasket made of rubber is positioned inside the notches to help make a seal when you insert your portafilter. The notches permit precise placement of the portafilter. This is crucial for an accurate extraction.
The group head is not just able to allow you to insert your portafilter easily but also maintains the temperature at a constant level. It does this by circulating hot water through the brew pan and around the portafilter, ensuring that it's always at the right temperature to extract. This is important, as even a small difference in temperature can make the difference between a good and excellent espresso machines for home.
The Pump
Contrary to manual piston machines that use a lever to pressurize water, rotating decent espresso machine machines rely upon motorized pumps to supply the nine atmospheric bars of pressure needed to extract espresso. This pressure is built up by pumping water through a heat-exchanger and then through the ground coffee.
(Image: https://cdn.freshstore.cloud/offer/images/778/2238/de-longhi-dedica-style-traditional-pump-espresso-machine-coffee-and-cappuccino-maker-ec685m-1-liter-silver-2238.jpg)Pumps tend to be cheaper than piston-driven machines, and tend to last longer. However, both types of machines may get damaged through overuse and lack of cleaning. They also add mechanical complexity that can lead to the cost of even the simplest models.
Some espresso machines make use of steam pressure instead of a pump for brewing espresso. The drawback of this is that the boiler that produces steam also raises the temperature of the water until it reaches boiling and can result in excessive extraction. The machines also need to constantly rebuild their pressure between cups. This requires energy and time.
Many espresso machines employ the rotary or vibration pump, with a vibration model using a vibrating disc to create the pressure, and a rotary model pushing hot water through the grounds under high speed. Both machines can produce excellent espresso, however rotary machines are more stable, quieter and less likely to break.
The Boiler
The boiler is the element that heats water to the ideal temperature to extract. The resulting steam is then transferred to the portafilter containing the ground espresso coffee, and is then pumped down into the cup. The steam is able to create enough pressure to push the grounds of coffee through. This results in a layer of crema that is then poured over. This is a hallmark of a good espresso.
There are three distinct types of espresso machines, each having distinct pumps and the temperature of the brew. There are many ways to control the brew and the size of the cup that can be produced by the machine.
The first espresso machines were steam-type. The first italian espresso machine machines were steam types. The coffee tasted bitter and burnt. The modern espresso machine was invented by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.
The most well-known espresso maker is a semiautomatic machine with an electric pump. When people think of espresso machines, they picture these machines. Semi-automatic machines require you to grind and tamp the beans yourself while the pump controls the flow of water and pressure. This is an excellent solution that combines human control with mechanized reliability.
The Filter
Espresso machines usually use filters that separate the grounds of the coffee from hot water. The filter is also a vital part of the machine's temperature control, as it helps prevent overheating.
A filter also improves flavor, as it permits a longer flowering phase. This helps the beans release their flavor and gives the chance for better extraction.
It is important to remember that even the finest filter could result in a poor cup of coffee. The quality of the beans and the extraction, remain crucial.
It's in this area that the magic occurs. This is what makes espresso taste so delicious. The grouphead, sometimes referred to as the brew head, is where the portafilter (the container you place the coffee ground into) is placed when you're making espresso makers.
Steam-driven espresso machines use hot water that is heated in an airtight container to make steam. The steam then pushes hot water through coffee grounds under high pressure. These machines are cheaper and are easier for the user to maintain than pumps-driven models. However, they are not as efficient in their capacity to create the ideal conditions for brewing since they operate at 1-1.5 bars of pressure, while the perfect shot requires 9-10 bars.
In recent years, compressed air-driven espresso machines have become more popular. They make use of an air compressor to push hot water through the ground. They are also more mobile than steam-driven electric espresso machines.