The Main Issue With Machine Espresso, And How You Can Resolve It

How Does Machine Espresso Work?

Machine espresso makes use of precise pressure and amazing filter technology to make the perfect cup of coffee. How does it work exactly?

To make an espresso 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 Head of the Group

As the name implies the group head is where you insert your portafilter when making espresso. It distributes water into the portafilter, and regulates the pressure during the extraction. There are a variety of group heads each with their own advantages and drawbacks. Some focus on temperature stability, others on pre-infusion options, and others are designed to control the lever. There are also some that come with a range of features, such as the E61, which is to be the most popular among baristas for its ability to offer multiple benefits in a single package.

As you can see from the image above the head of the group is fitted with several notches. You can place your portafilter in these notches and then turn the head around to secure it. There is also a gasket made from rubber in the notches, which helps create an airtight seal after inserting your portafilter into the machine. The notches on the head allow for an exact placement of the portafilter, which is essential to ensure an efficient extraction.

In addition to allowing you easily insert your portafilter, the group head is responsible to ensure that the temperature remains even. It does this by circulating hot water through the brew basket, and around the portafilter, ensuring that it is always at the correct temperature for extraction. This is important because even a few degrees can make the difference between a good and excellent espresso.

The Pump

Unlike manual piston machines, which use a lever to pressurize water, rotating espresso machines rely upon motorized pumps to provide the nine atmospheric bars of pressure required for espresso extraction. The pressure builds by removing tap water from a reservoir, and pumping it through a heat exchanger prior to being pumped through the ground coffee inside the group head.

Pumps are generally 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 can increase the cost of even the simplest models.

Some espresso machines do away with the pump completely and utilize steam pressure to make espresso. The downside is that the boiler that produces steam also raises the temperature of the water to the point of boiling which could lead to excessive extraction. The machines also need to constantly rebuild their pressure between cups. This takes energy and time.

Many espresso machines make use of a rotary or vibration pump. A vibration model makes use of an oscillating disk to create pressure, whereas a circular model pushes hot liquid through the ground at a fast speed. Both machines can produce excellent espresso, but rotary machines are more stable, quieter and less likely to fail.

The Boiler

The boiler is used to heat the water to a temperature that is ideal to extract. The resulting steam reaches the portafilter containing the ground espresso coffee and is then pumped into the cup. The steam creates pressure to push through the grounds of the coffee. This results in a crema on the top of the espresso. This is the hallmark of a great espresso.

There are espresso home machine of espresso makers, and they differ in the type of pump they use and how hot the brew is. There are a variety of ways to control the brew as well as the size of the cup that can be made by the machine.

The first espresso machines were steam-types. The first espresso machines were steam-type machines. This led to the coffee tasting burnt and bitter. This is why the Milanese producers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.

The most common espresso machine is a semiautomatic with an electric pump. These are the things people think of when they imagine an espresso machine. With a semi-automatic espresso machine, you grind the beans and then tamp them by hand. The pump is able to regulate the flow of water and pressure. This is a great compromise between the human touch and mechanized consistency.

The Filter

Typically, espresso machines use filters to separate the coffee grounds as they pass through the hot water. The filter is also a vital element of the machine's temperature control, since it stops overheating.

It also helps with flavor, as a filter allows 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 high-quality filter can result in a poor cup of coffee, since the quality of the beans and extraction is still crucial.

It's here that the magic happens. This is what makes espresso taste so good. The grouphead, also called the brewhead, is where the portafilter (the device you put the coffee grounds into) sits when you're making espresso.

In a steam-driven espresso machine, hot water is heated in an airtight tank to create steam. Steam is then pushed through the grounds with high pressure. These machines are less expensive and easier for the user to maintain than pumps-driven models. They are however limited for creating the ideal conditions for brewing since 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 been gaining popularity. They utilize an air compressor to force hot water through grounds and are significantly more portable than steam-driven electric machines.