10 Things That Your Family Taught You About Machine Espresso

How Does Machine Espresso Work?

Machine espresso employs precise pressure and amazing filter technology to make the delicious coffee we enjoy. But how exactly does it work?

To make espresso hot water is pushed under pressure through finely ground coffee. The process is similar to that of making drip coffee. However, it is the pressure that makes the main difference.

The Head of the Group

The name implies, the group head is where you place your portafilter when brewing espresso. It distributes water into the portafilter and regulates the pressure during the extraction. There are numerous kinds of group heads each with its own advantages and drawbacks. Some are focused on temperature stability, whereas others on pre-infusion options, and others are designed to control the lever. There are even some that have a combination of features, like the E61 one, which is the most popular choice among baristas due to its capacity to provide multiple benefits in one package.

As you can see from the photo above the group head is fitted with several notches. You place your portafilter in these notches, then twist the head to lock it. There is also a gasket made from rubber that resides inside the notches and helps create an airtight seal when you insert your portafilter into the machine. The notches on the head permit a precise positioning of the portafilter which is necessary to ensure an efficient extraction.

In addition to allowing you effortlessly insert your portafilter the group head is also responsible to ensure that the temperature remains even. This is done by cycling hot water around the portafilter, and through the brew-basket, ensuring that the temperature is always at the right level to extract the coffee. This is important, as even a few degrees can make the difference between excellent and great espresso.

The Pump

The motorized pumps that are used in rotary espresso machines provide the nine atmospheric bar pressure that is required for espresso extraction. This is different from manually operated piston machines that employ levers. This pressure builds up by removing tap water from a reservoir, and pumping it through a heat exchanger prior it is shot through the ground coffee in the group head.

Pumps tend to be less expensive than piston-driven machines, and tend to last longer, however both types of machines can be damaged by excessive use and inadequate cleaning. Pumps are also more complex mechanically, and can add to the cost of even simple models.

Some espresso machines make use of steam pressure instead of a pump to make espresso. The downside is that the same boiler that produces steam also increases the temperature of water to boiling and can result in over-extraction. In addition these machines are often required to restore their pressure between cups, which takes time and energy.

A large majority of espresso machines employ the rotary or vibration pump. A vibration model utilizes an oscillating disk to create pressure, while the Rotary model pushes hot coffee through the ground at high speed. Both machines espresso machines can make great espresso, but rotary machines are more stable, quieter and less likely to fail.

The Boiler

The boiler is what makes the water warm to the perfect temperature for extraction. The steam that is produced reaches the portafilter, which is the container that holds the espresso coffee grounds. It is then funneled into the cup. The steam creates enough pressure to push the grounds of the coffee through. This results in a whipped-up top of the espresso. This is one of the main characteristics of a great best espresso machine under 200.

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

The first best espresso machine under 200 machines were steam-types. They utilized a single boiler to make both steam and brew, but the pressure they could produce was very low - just two bars of atmospheric pressure, at most. The coffee tasted bitter and burnt. The modern espresso machine was created by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.

The most common espresso maker is a semi-automatic device with an electric pump. These are the images people have when they think of an espresso maker. If you have a semi-automatic machine you grind the beans and 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 the mechanised quality.

The Filter

Typically, espresso machines employ filters that separate the grounds of coffee when they pass through the hot water. The filter is also an essential part of the temperature control system, as it prevents the machine from overheating.

A filter also improves flavor, as it permits the beans to flower for a longer period of time. This allows the beans to release their flavors, and improves extraction.

However it is crucial to remember that even a top filter can result in a poor cup of coffee, since the quality of the beans and extraction are important.

It's here that the magic occurs. This is what makes espresso taste so delicious. The grouphead, often called the brew head, is where the portafilter (the device you put the coffee ground into) sits when you're making espresso.

Steam-driven espresso machines make use of hot water heated in an airtight container to produce steam. The steam then pushes hot water through the coffee grounds under high pressure. These kinds of machines tend to be less expensive and easier to maintain than pumps-driven models. They are however limited in their ability to create the perfect conditions for brewing as they only operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

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