How To Explain Machine Espresso To A Five-Year-Old How Does Machine Espresso Work?

mini espresso machine utilizes precise pressure and mind-blowing filter technology to make the delicious coffee we enjoy. How exactly does it work?

Espresso is made by pushing hot water under high pressure through finely-ground coffee. The process is similar to making drip coffee but the difference is in the pressure.

The Group Head

The group head is the portafilter is inserted when you are making espresso. It disperses water into the portafilter and controls the pressure of the extraction. There are many different types of group heads each with distinct advantages and drawbacks. Some focus on temperature stability, while others on pre-infusion options, and others are designed to control the lever. Some have a combination, such as the E61. This is a preferred choice for baristas because it offers multiple benefits in one package.

As you can see in the photo above The group head features several notches where you place your portafilter before twisting it manually to lock it in. A rubber gasket is located within the notches to create a seal while you insert your portafilter. The notches allow for precise placement of your portafilter. This is crucial for an accurate extraction.

The group head does not just allow you to insert your portafilter easily however, it also keeps an even temperature. This is accomplished by cycling hot water around the portafilter and through the brew basin, ensuring that the temperature is always at the right level to extract the coffee. It is crucial to keep in mind that even a tiny difference can make the difference between a good and a great espresso.

The Pump

In contrast to manual piston machines which rely on a lever that pressurize water, rotating espresso machines rely upon motorized pumps that provide the nine atmospheric bars of pressure required to extract espresso. The pressure is created by drawing tap water from a reservoir, and pumping it through a heat exchanger prior to being pushed through the ground coffee in the group head.

Pumps are typically more affordable and last longer than piston-driven machines. However, both kinds of machines can deteriorate due to excessive use and poor cleaning. They also make mechanically complex that can lead to the cost of even the most basic models.

Certain espresso machines remove the pump entirely and employ steam pressure to create espresso. The downside is that the same boiler that produces steam also raises the temperature of water until it reaches boiling and can result in over-extraction. They also have to constantly rebuild their pressure in between cups. This takes energy and time.

Many espresso machines use an rotary or a vibration pump. A vibration model uses a rotating disk to generate pressure, whereas a circular model pushes hot liquid through the ground at a fast speed. Both models are capable of producing excellent espresso, but the rotary pumps are quieter, and more durable than vibration pumps.

The Boiler

The boiler is the part that heats water to the ideal temperature to extract. The resultant steam then reaches the portafilter, which contains the ground espresso coffee and is then pumped down into the cup. The steam creates pressure that pushes through the grounds of the coffee. This creates a layer crema on top. This is a hallmark of a great espresso.

There are three types of espresso makers, which differ in the type of pump they employ and the degree of heat that the brew is. There are various ways to control the strength of the brew and the size of cup that can be made by the machine.


The earliest espresso machines were steam type. They employed only one boiler to make both steam and brew, however the pressure they were able to produce was very low - just two bars of atmospheric pressure at most. The coffee tasted bitter and burned. This is why the Milanese producers 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. When people think of espresso machines, they imagine these machines. Semi-automatic machines require you to grind and tamp your beans yourself The pump, however, regulates the water flow and pressure. This is a great compromise between the human touch and the mechanised consistency.

The Filter

Espresso machines usually use filters that separate the coffee grounds from the hot water. The filter is also an essential component of the machine's temperature control, as it helps prevent overheating.

A filter also improves flavor as it allows for a longer flowering period. This lets the beans let their nuances out, and allows for a better extraction.

It is important to remember that even the most efficient filter can produce a bad cup of coffee. The quality of the beans and the extraction, remain crucial.

This is where the magic happens, and it's what makes an espresso really taste good. The grouphead, often called the brewhead, is where the portafilter (the thing you put the ground coffee in) is placed when you're making espresso.

In an espresso machine that is driven by steam, hot water is heated in an airtight container to create steam. This is then pushed through the grounds under high pressure. These machines are cheaper and are easier for the user to maintain than pumps-driven models. They are however limited to create the perfect 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 into the grounds and are much more portable than steam-driven electric machines.