Three Common Reasons Your Machine Espresso Isn't Working (And How To Fix It)

How Does Machine Espresso Work?

Machine espresso makes use of precise pressure and mind-blowing filter technology to create the delicious coffee we enjoy. How exactly does it work?

To make an espresso hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee however the main difference lies in the pressure.

The Group Head

The name implies, the group head is where you put your portafilter in when brewing espresso. It is responsible for dispersing water into the portafilter before controlling the pressure of the extraction. There are a variety of group heads, each with its own advantages and drawbacks. Some focus on temperature stability, others on pre-infusion capabilities, while others are designed to control the lever. Some come with a combination of both, like the E61. This is a favorite among baristas because it offers multiple advantages in a single package.

As you can see from the picture above, the group head has a number of notches. You place your portafilter in these notches, then twist the head to secure it. A rubber gasket is located inside the notches to help create a seal as you insert your portafilter. The notches allow for an exact placement of the portafilter. This is vital for a consistent extraction.

In addition to allowing you easily insert your portafilter, the group head is also responsible to ensure that the temperature remains even. It does this by cycling hot water through the brew basket and around the portafilter, making sure that it's always at the right temperature to extract. It is important to remember that even a tiny differences can make the distinction between a good and great espresso.

The Pump

In contrast to manual piston machines which rely on a lever to pressurize water, rotary espresso machines rely on motorized pumps that provide the nine atmospheric bars of pressure that are required to extract espresso. This pressure is built up by pumping water through a heat exchanger and then through the ground coffee.

Pumps tend to be less expensive than piston-driven machines, and tend to last longer, however both types of machines may get damaged through overuse and lack of cleaning. Pumps are also more complex mechanically, which could increase the price of even the simpler models.

Some espresso machines do away with the pump completely and employ steam pressure to create espresso. This can lead to over-extraction as the boiler that makes steam also heats the water until it comes to a boil. In addition these machines typically have to rebuild their pressure between cups, which requires time and energy.

A majority of espresso machines use a vibration or rotary pump, which has a vibration model that uses a vibrating disc to create pressure and an rotary model that pushes hot water through the grounds at high speed. Both models can make 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 to extract. The steam produced is then directed to the portafilter, which is a container for espresso grounds. It is then funneled into the cup. During this process the steam is able to create enough pressure to push the grounds of coffee through. This creates a crema on top of the espresso. This is one of the hallmarks of a good espresso.

There are three kinds of espresso machines, each with different types of pumps and brew temperature. There are different ways to control the strength of the brew and the size of cup that can be produced by the machine.

The earliest espresso machines were steam-based. They used one boiler to make steam and brew, however the pressure they were able to produce was not very high - two bars of atmospheric pressure maximum. This resulted in the coffee tasting bitter and burnt. The modern espresso machine was created by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.

The most well-known espresso machine is a semiautomatic that has an electric pump. When people think of espresso machines, they picture these machines. With a semi-automatic espresso machine, you must grind the beans and then tamp them yourself but the pump regulates the flow of water and pressure. This is a perfect compromise between human control and mechanised consistency.

The Filter

Espresso machines usually use a filter that separates the grounds of the coffee from hot water. The filter is also a vital element of the machine's temperature control, since it helps to prevent overheating.

A filter also helps with flavor, as it permits a longer flowering phase. This allows the beans to let their nuances out, and also allows for better extraction.

However, it is important to keep in mind that even a top filter can produce a bad cup of coffee, since the quality of the beans and extraction is crucial.

This is where the magic happens. It's what makes an espresso really taste great. espressomachines (also known as the brewhead) is where you put the portafilter, the thingy used to place the coffee grounds into, when making espresso.

Steam-driven espresso machines make use of hot water that is heated in an airtight container to create steam. The steam then pushes hot water into the coffee grounds under high pressure. These kinds of machines are usually cheaper and easier to maintain than pump-driven models. They are however limited in their ability to create the perfect brewing conditions as they only operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

In recent years, compressed air pump-driven espresso machines have become more popular. They make use of an air compressor to push hot water across the ground and are more mobile than electric steam-driven espresso machines.