9 . What Your Parents Taught You About Machine Espresso

How Does Machine Espresso Work?

Machine italian espresso machine makes use of precise pressure and incredible filter technology to produce the perfect cup of coffee. How does it work exactly?

To make cafe espresso machine, hot water is pushed under 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 when making espresso. It is responsible for dispersing the water into the portafilter and then controlling the pressure of the resulting extraction. There are many different kinds of group head, each with their own advantages and disadvantages. Some are designed to provide temperature stability while others are built to handle pre-infusion. Some are designed to control the lever. Some have a combination of features, such as the E61 one, which is to be the most popular among baristas for its ability to offer multiple perks in one package.

As you can see in the photo above, the group head has several notches where you place your portafilter before twisting it manually to lock it in. A gasket of rubber is situated within the notches to create a seal while you insert your portafilter. The notches permit an exact placement of the portafilter. This is vital for an efficient extraction.

Apart from allowing you easily insert your portafilter, the group head is responsible for maintaining an even temperature. It does this by cycling hot water through the brew container and around the portafilter, ensuring that it's always at the right temperature to extract. This is important, as even a few degrees can be the difference between a good and excellent espresso.

The Pump

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

Pumps are generally more affordable and last longer than piston-driven machines. However, both types of machines can degrade because of excessive use and inadequate cleaning. Pumps are also more complex mechanically, which can raise prices of even simplest models.

Some espresso machines employ steam pressure instead of a pump for brewing espresso. This could lead to over-extraction since the boiler that produces steam also heats the water to boil. Additionally the machines often have to restore their pressure between cups, which requires time and energy.

A majority of espresso machines espresso machines use the rotary or vibration pump, with a vibrating model using a rotating disc to create pressure, and a rotary model pushing hot water through the grounds under 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 the element that heats water to an ideal temperature for extraction. The resulting steam reaches the portafilter, which contains ground espresso beans and is then pumped into the cup. The steam is able to create enough pressure to push the coffee grounds through. This creates a layer crema on top. This is one of the hallmarks of a great espresso.

There are three kinds of espresso machines, each having different pumps and brew temperature. There are also different ways that the brew can be controlled, as well as the size of the cup that the machine can produce.

The first espresso machines were steam-type. They used only one boiler to make both steam and brew but the pressure they could produce was very low - just two bars of atmospheric pressure at the most. This led to the coffee tasting burnt and bitter. This is the reason Milanese producers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

The most well-known espresso maker is a semi-automatic one with an electric pump. These are the images people have when they think of an espresso maker. With a semi-automatic machine, you need to grind the beans and tamp them by hand, but the pump controls the flow of water and pressure. This is an excellent combination of human control and mechanised accuracy.

The Filter

Typically, espresso machines utilize filters to separate the grounds of the coffee as they go through the hot water. The filter is also an important part of the temperature control system as it keeps the machine from overheating.

A filter can also help with flavor as it allows for the beans to flower for a longer period of time. This allows the beans to let their nuances out, and allows for a better extraction.

However, it is important to keep in mind that even a great filter can result in a poor cup of coffee, as the quality of the beans and extraction is crucial.

This is where the magic happens, it's what makes an espresso really taste great. The grouphead, often referred to as the brew head, is where the portafilter (the container you place the coffee ground into) is placed when making espresso.

In the steam-driven espresso machine hot water is heated in an airtight tank to create steam. Steam then pushes the hot water through the grounds at high pressure. These kinds of machines tend to be less expensive and simpler to maintain than pump-driven models. They are however limited for creating the ideal brewing conditions 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 become more popular. They use an air compressor to push hot water through the ground. They are also more mobile than electric steam-driven espresso machines.