How Does Machine Espresso Work?

The machine espresso is made using precision pressure, and filtering technology that is amazing to make the coffee you enjoy. But how exactly does it work?

To make Buy Espresso Makers, hot water is forced under high pressure through finely ground coffee. The process is similar to making drip coffee. However, the pressure is the major difference.

The Head of the Group

The name implies, the group head is where you place your portafilter when brewing espresso. It is responsible for dispersing water into the portafilter and then controlling the pressure of the extraction. There are many different kinds of group head each with its distinct advantages and disadvantages. Some are specifically designed for stability in temperature, while others are specifically designed to handle pre-infusion. Others are built to control the lever. There are also some that come with a range of features, like the E61, which is considered the classic choice among many baristas for its ability to offer multiple perks in one package.

As you can see in the above photo the group head has a number of notches. You can place your portafilter in these notches, then twist the head to lock it. A gasket made of rubber is placed in the notches to create a seal when you insert your portafilter. The notches allow for an exact placement of the portafilter. This is vital for a consistent extraction.

Aside from allowing you to easily connect your portafilter, the group head is also responsible to maintain an even temperature. This is achieved by cycling hot water around the portafilter and through the brew-basket, ensuring the temperature is always right to extract the coffee. It is important to realize that even a few degree difference can make the difference between a decent and a great mini espresso machine.

The Pump

Contrary to manual piston machines which use a lever to pressurize water, rotary espresso machines rely on motorized pumps to provide the nine atmospheric bars of pressure necessary for espresso extraction. This pressure builds up by drawing tap water from a reservoir, and pumping it through a heat exchanger prior to being shot through the ground coffee inside the group head.

Pumps tend to be cheaper than piston-driven machines, and they tend to last longer, although both types of machines can become damaged due to excessive use and poor cleaning. They also make mechanically complex, which can result in costly prices for even the simplest models.

Some small espresso machine machines use steam pressure instead of a pump for brewing espresso. This can cause over-extraction because the boiler that produces steam also heats the water until it comes to a boil. In addition these machines are often required to rebuild their pressure between cups, which takes time and energy.

Many espresso machines employ an rotary or vibrating pump, which is a vibration model using a vibrating disc that generates the pressure, and rotating models that push hot water through the grounds at high speed. Both machines produce great espresso but rotary machines are more quiet, durable and less likely to break down.

The Boiler

The boiler is the one that is used to heat the water to the right temperature for extraction. The steam produced reaches the portafilter, which is a container for espresso grounds. The steam is then channeled into the cup. During this process the steam creates enough pressure to push the coffee grounds through. This results in a whipped-up the top espresso machines of the retro espresso machine. This is the hallmark of a great espresso.

There are three kinds of espresso makers, which differ in the type of pump they employ and how hot the coffee is. There are different ways to control the brew and the size of cup that can be produced by the machine.

The first espresso machines were steam-types. They used one boiler to create both steam and brew however, the pressure they could produce was very low - just two bars of atmospheric pressure at 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 commonly used espresso machine is a semiautomatic model with an electric pump. These are what people imagine when they think of an espresso maker. With a semi-automatic machine, you grind the beans and tamp them by hand, but the pump regulates the flow of water and pressure. This is a great compromise between the human touch and the mechanised accuracy.

The Filter

Typically, espresso machines use filters to separate the grounds of coffee when they pass through the hot water. The filter is also a crucial part of the temperature control system because it stops the machine from overheating.

It also helps with flavor, since a filter lets you enjoy a longer bloom phase. This allows beans to release their flavors and provides an opportunity for a better extraction.

However, it is important to remember that even a great filter can make a terrible cup of coffee, as the quality of the beans and extraction is still essential.

This is where the magic happens, it's the thing that makes espresso taste great. The grouphead, also called the brew head, is the place where the portafilter (the thingy you put the coffee grounds into) is placed when making espresso.

Steam-driven espresso machines make use of hot water heated in an airtight container to produce steam. The steam then moves hot water through the grounds of coffee at high pressure. They are less expensive and easier for the owner to maintain than pumps-driven models. However, they are not as efficient in their ability to produce the perfect brewing conditions 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-pump-driven espresso machines have become more popular. They utilize an air compressor to push hot water across the ground and are more mobile than steam-driven electric espresso machines.