9 Lessons Your Parents Taught You About Machine Espresso

How Does Machine Espresso Work?

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

In order to make espresso hot water is pushed under pressure through finely ground coffee. The process is similar to that of making drip coffee. However the pressure is the primary difference.

The Head of the Group

As the name implies, the group head is where you place your portafilter when making espresso. It distributes water into the portafilter, and then regulates the pressure of extraction. There are many different types of group heads, each with its own advantages and disadvantages. Some focus on temperature stability, whereas others on pre-infusion options, and others are designed to control the lever. Some include a mix of features, like the E61 that is the standard choice for many baristas for its ability to provide multiple benefits in one package.

As you can see in the picture above, the group head is fitted with a variety of notches. You can place your portafilter in these notches and then twist the head to secure it. There is also a gasket of rubber that resides inside the notches to help create a seal when you insert your portafilter into the machine. The notches allow for an exact placement of the portafilter. This is vital for a consistent extraction.

Aside from allowing you to easily place your portafilter in, the group head is responsible for maintaining a consistent temperature. This is done by cycling hot water around the portafilter, and through the brew-basket, making sure the temperature is always right to extract the coffee. This is vital, because even a few degrees can make the difference between a excellent and great espresso.

The Pump

The motorized pumps that are used in travel espresso maker machines that rotate provide the nine atmospheric bar pressure that is required for espresso extraction. 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 prior to being pumped through the ground coffee inside the group head.

Pumps are generally cheaper and last longer than piston-driven machines. However, both types of machines are susceptible to degrading because of excessive use and insufficient cleaning. Pumps are also more complicated mechanically, which can raise the price of even the most basic models.

Some espresso machines employ steam pressure instead of a pump for brewing espresso. The drawback of this is that the boiler that produces steam also increases the temperature of the water until it reaches boiling which could lead to over-extraction. These machines also have to continually rebuild their pressure between cups. This takes energy and time.

Many espresso machines make use of either a vibration or rotary pump. A vibration model employs an oscillating disk to create pressure, whereas a Rotary model pushes hot coffee through the ground at a high speed. Both machines can make excellent espresso, but rotary machines are quieter, more durable and less likely to break.

The Boiler

The boiler heats the water to the right temperature for extraction. The steam produced gets to the portafilter which contains the espresso coffee grounds. It is then poured into the cup. During this process the steam is able to create enough pressure to push the grounds of coffee through. This results in a layer crema on top. This is the hallmark of a good espresso.

There are three kinds of espresso makers. They differ in the type of pump they employ and how hot the brew is. There are different ways that the brew can be controlled as well as the size of the cup that the machine is capable of making.

The first espresso machines were steam type. The first espresso machines were steam-type machines. The coffee tasted bitter and burned. This is the reason Milanese makers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.

The most well-known espresso maker is a semi-automatic one with an electric pump. When people think of espresso machines, they envision these machines. Semi-automatic machines require you to grind and tamp the beans yourself, but the pump regulates the flow of water and pressure. This is a great compromise between human control and mechanised consistency.

The Filter

Typically, professional espresso machine for home machines have filters to separate the grounds of coffee as they move through the hot water. The filter is also an essential component of the machine's temperature control, as it prevents overheating.

Filters also aid in flavor as it allows for an extended flowering time. This allows the beans to release their flavors and provides an opportunity for a better extraction.

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

It's in this area that the magic takes place. This is the reason why espresso tastes so good. The grouphead (also known as the brewhead) is where you place the portafilter, which is the thingy that you put the grounds of coffee into while making espresso.

In the steam-driven espresso machine hot water is heated in an airtight tank to create steam. This is then pushed through the grounds at high pressure. These machines are less expensive and easier for the user to maintain than pumps-driven models. However, they are limited in their ability to provide the ideal brewing conditions, because they operate at 1-1.5 bars of pressure. The perfect shot requires 9-10 bars.

In recent years, espresso machines powered by a compressed air compressor have become increasingly popular. They utilize an air compressor to push the hot water through the grounds and are significantly more portable than electric steam-driven machines.