How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and mind-blowing filter technology to make the perfect cup of coffee. How does it work exactly?

In order to make espresso hot water is forced under high pressure through finely ground coffee. The process is similar to making drip coffee but the key difference is in the pressure.

The Head of the Group

The group head is the portafilter that you place in the espresso maker when making it. It is responsible for dispersing water into the portafilter, and controlling the pressure that results from the extraction. There are numerous kinds of group heads each with its own advantages and drawbacks. Some are designed to provide the stability of temperature while some are designed to handle pre-infusion. Others are built to control the lever. Some are a combination, like the E61. This is a preferred choice for baristas as it provides a variety of benefits in one package.

As you can see in the image above the group head is made up of numerous notches that you can put your portafilter, then twist it with your hands to secure it. A gasket of rubber is situated within the notches to create a seal while you insert your portafilter. The notches on the head allow for an exact placement of the portafilter, which is necessary for a consistent extraction.

Aside from allowing you to effortlessly insert your portafilter the group head is also responsible for maintaining an even temperature. It does this by circulating hot water through the brew basket and around the portafilter to ensure that it is always at the right temperature for extraction. This is important, as even a small difference in temperature can mean the difference between excellent and great espresso.

The Pump

The motorized pumps in rotary espresso machines supply the nine atmospheric bar pressure required for espresso extraction. This is different from manual piston machines that use levers. This pressure builds up by drawing tap water from a reservoir, and pumping it through a heat exchanger prior to being pushed through the ground coffee inside the group head.

Pumps are generally cheaper and last longer than piston-driven machines. However, both types of machines may degrade due to overuse and poor espresso maker cleaning. Pumps are also more complicated mechanically, which can raise the cost of even most basic models.

Certain espresso machines utilize steam pressure instead of a pump in order to brew espresso. The drawback is that the same boiler that produces steam also raises the temperature of water until it reaches boiling which can cause excessive extraction. Additionally, these machines frequently have to restore their pressure between cups, which takes time and energy.

A majority of espresso machines utilize the rotary or vibration pump. A vibration model uses an oscillating disk to create pressure, whereas the rotary model pushes hot water through the ground at high speed. Both machines can produce excellent espresso, but rotary machines are more stable, quieter and less likely to break down.

The Boiler

The boiler will heat the water to the ideal temperature for extraction. The steam created will eventually reach the portafilter, which is a container for espresso grounds. It is then funneled into the cup. During this process the steam causes enough pressure to push the grounds of coffee through. This results in a layer of crema on top. This is the hallmark of a good espresso coffee machine uk.

There are three kinds of espresso makers. They differ in the type of pump they use and how hot the coffee is. There are different ways that the brew can be controlled and the size of the cup that the maker can create.

The first espresso machines were steam type. The earliest best espresso maker machines were steam-type machines. This led to the coffee tasting burnt and bitter. This is why Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.

The most well-known espresso maker is a semi-automatic one that has an electric pump. This is what people envision when they think of an espresso maker. Semi-automatic machines require you to grind and tamp the beans by yourself, but the pump regulates the flow of water and pressure. This is a great solution that combines human control with mechanised accuracy.

The Filter

Espresso machines usually have a filter that separates the grounds of coffee from hot water. The filter is also an essential part of the machine's temperature control, since it stops overheating.

A filter can also help with flavor, as it permits a longer flowering period. 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 high-quality filter can result in a poor cup of coffee as the quality of the beans and extraction is still important.

It's in this area that the magic takes place. This is what makes espresso taste so delicious. The grouphead (also known as the brewhead) is where you place the portafilter, which is the thingy that you use to put the grounds of your coffee into when making espresso.

Steam-driven espresso machines use hot water that is heated inside an airtight container to produce steam. The steam then moves hot water through the coffee grounds under high pressure. These machines are cheaper and easier for the user to maintain than pumps-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 been gaining popularity. They utilize an air compressor to push hot water through grounds and are much more portable than steam-driven electric machines.