How Does Machine Espresso Work?

Machine espresso employs precise pressure and mind-blowing filter technology to create the delicious coffee we enjoy. What exactly is it that makes 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 pressure is the main difference.

The Group Head

The group head is the portafilter you put in when making espresso. It disperses water in the portafilter, and then controls the pressure of the extraction. There are many different kinds of group head, each with their unique advantages and drawbacks. Some are focused on temperature stability, some on pre-infusion options, and others are designed to control the lever. There are some that have a combination of features, such as the E61 one, which is the standard choice for many baristas for its ability to offer multiple benefits in a single package.

As you can see in the above image the group head comes with several notches where you place your portafilter and then twist it by hand to lock it in. A gasket of rubber is situated within the notches to create a seal when you insert your portafilter. The notches permit an exact placement of the portafilter. This is vital for an accurate extraction.

The group head is not just able to allow the portafilter to be inserted easily however it also keeps a constant temperature. This is done by cycling hot water around the portafilter, and through the brew-basket to ensure that the temperature is always at the right level to extract the coffee. This is important, as even a small difference in temperature can mean the difference between good and great espresso.

The Pump

Motorized pumps in rotary espresso machines provide the nine atmospheric bar pressure that is required to extract espresso. This is different from manual piston machines which use levers. The pressure builds by drawing tap water from a reservoir and pumping it through a heat exchanger before being pumped through the ground coffee inside the group head.

Pumps are typically less expensive and last longer than piston-driven machines. However, both kinds of machines may degrade because of excessive use and inadequate cleaning. They also add mechanical complexity, which can result in an expensive price for even the simplest models.

Some espresso machines remove the pump completely and use steam pressure to brew espresso. The disadvantage of this is that the boiler that produces steam also raises the temperature of water to boiling which can cause excessive extraction. These machines also have to constantly rebuild their pressure between cups. This takes energy and time.

A majority of espresso machines utilize a rotary or vibration pump. A vibration model employs an oscillating disk to create pressure, whereas a Rotary model pushes hot coffee through the ground at high speed. Both models are capable of producing excellent travel espresso maker, but Rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler is what makes the water warm to the right temperature to extract. The resulting steam is then transferred to the portafilter containing ground espresso beans and gets funnelled down into the cup. During this process the steam generates enough pressure to push the grounds of the coffee through. This creates a layer crema on top. This is the hallmark of a great italian espresso machine.

There are three types of espresso makers, which differ in the kind of pump they use and how hot the coffee is. There are a variety of ways that the brew may be controlled and the size of the cup that the machine can make.

The first espresso machines were steam-type. They used one boiler to create both brew and steam, but the pressure they could create was minimal - two bars of atmospheric pressure, at most. This led to the coffee tasting burnt and bitter. The modern Espresso maker for home machine was developed by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.

The most commonly used espresso maker is a semi-automatic device with an electric pump. When people think of espresso machines, they envision these machines. With a semi-automatic machine, you have to 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 mechanized accuracy.

The Filter

Typically, espresso machines use a filter to separate out the grounds of coffee when they pass through the hot water. The filter is also a vital component of the temperature control system, as it prevents the machine from overheating.

It also enhances flavor as a filter allows for a more prolonged bloom time. This allows beans to release their nuances and gives an opportunity to improve extraction.

However, it is important to remember that even a great filter could result in a bad 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 an espresso really taste great. The grouphead (also called the brewhead) is where you put the portafilter, the device that you put the grounds of your coffee into when making espresso.

Steam-driven espresso machines make use of hot water heated in an airtight container to make steam. The steam then pushes hot water through grounds of the coffee under pressure. They are less expensive and easier to maintain than pumps-driven models. However, they are not as efficient in their capacity to create the ideal conditions for brewing since they operate at 1-1.5 bars of pressure. However, the perfect shot requires 9-10 bars.

In recent years, espresso machines driven by compressed air-pump have become increasingly popular. They make use of an air compressor to force hot water into the ground and Espresso Maker For Home are much more mobile than steam-driven electric espresso machines.