13 Things About Machine Espresso You May Not Have Known

How Does Machine Espresso Work?

Machine espresso employs precise pressure and incredible filter technology to produce the perfect cup of coffee. What exactly is it?

Espresso is produced by pushing hot water at high pressure through finely-ground coffee. The process is similar to that of making drip coffee. However, the pressure is the primary difference.

The Group Head

As the name suggests the group head is the place you place your portafilter while making espresso. It disperses water in the portafilter, and then regulates the pressure of extraction. There are numerous kinds of group heads each with distinct advantages and disadvantages. Some are designed for temperature stability while others are specifically designed to handle pre-infusion. Others are made to control the lever. Some include a combination such as the E61. This is a preferred choice for baristas because it offers multiple advantages in one package.

As you can see in the above photo The group head features numerous notches that you can put your portafilter, then twist it manually to lock it in. There is also a gasket made from rubber that is a part of the notches and helps create an airtight seal after inserting your portafilter into the machine. The notches on the head allow for a precise positioning of the portafilter which is necessary to ensure an efficient extraction.

Apart from allowing you easily place your portafilter in, the group head is responsible for maintaining a consistent temperature. It does this by circulating hot water through the brew basket, and around the portafilter, making sure that it's always at the right temperature to extract. This is important, as even a small difference in temperature can be the difference between a excellent and great espresso.

The Pump

In contrast to piston machines that are manually operated, which use a lever to pressurize water, the rotary espresso machines use motorized pumps that provide the nine atmospheric bars of pressure needed to extract espresso. The pressure is created by drawing tap water from a reservoir and pumping it through a heat exchanger prior it is shot through the ground coffee inside the group head.

Pumps tend to be less expensive and last for longer than piston-driven machines. However, both kinds of machines can degrade because of excessive use and inadequate cleaning. They also make mechanically complex and can lead to the cost of even the simplest models.

Certain espresso machines do away with the pump entirely and use steam pressure to brew espresso. This can cause over-extraction because the boiler that produces steam also heats the water to boil. In addition these machines typically have to restore their pressure between cups, which takes time and energy.

Many espresso machines employ the rotary or vibration pump, with a vibrating model that uses a vibrating disc to create pressure and the rotary model pushing hot water through the grounds at high speed. Both models are capable of producing excellent espresso, but the rotary models 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 steam produced gets to the portafilter which is the container that holds the espresso coffee grounds. It is then poured into the cup. During this process, the steam creates pressure that pushes through the coffee grounds. This produces a layer of crema on top. This is the hallmark of a good espresso.

There are three types of espresso makers, which differ in the type of pump they use and the degree of heat that the espresso is. There are various ways in which the brew could be controlled and the dimensions of the cup the machine is capable of making.

The first espresso machines were steam-types. They had one boiler to create both steam and brew however, the pressure they could create was minimal - two bars of atmospheric pressure, at most. This resulted in the coffee tasting bitter and burnt. This is the reason Milanese makers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.

The most popular espresso machine is a semiautomatic one with an electric pump. These are the images people have when they think of an espresso machine. With a semi-automatic machine, you grind the beans and then tamp them yourself but the pump regulates the flow of water and pressure. This is an excellent compromise between human touch and mechanized quality.

The Filter

Espresso machines usually have filters that separate the grounds of the coffee from hot water. The filter is also an essential component of the temperature control system because it stops the machine from overheating.

It also improves flavor as a filter can allow for a longer bloom time. This allows beans to release their nuances and gives an opportunity for better extraction.

However, it is important to remember that even a great filter could result in a bad cup of coffee, because the quality of the beans and extraction are important.

It's click here 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, which is the thingy that you use to put the coffee grounds into, while making espresso.

In an espresso machine that is driven by steam, hot water is heated in an airtight tank to create steam. Steam then pushes the hot water through the grounds with high pressure. These kinds of machines are typically cheaper and easier to maintain than pumps-driven models. However, they are limited in their ability to create the ideal conditions for brewing since they are only operating 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 use an air-compressor to force hot water into the ground. They are also more mobile than steam-driven electric espresso machines.