The 9 Things Your Parents Taught You About Machine Espresso

How Does Machine Espresso Work?

Machine espresso uses precision pressure and mind-blowing filter technology to make the delicious coffee we enjoy. But how exactly does it work?

Espresso is created by forcing hot water 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 the place you place your portafilter when brewing espresso. It is responsible for dispersing water into the portafilter before controlling the pressure of the resulting extraction. There are a variety of group heads each with their own advantages and drawbacks. Some are focused on temperature stability, while others on pre-infusion features, and others are designed to control the lever. Some have a combination, like the E61. This is a preferred choice for baristas since it provides multiple advantages in one package.

As you can see in the above image, the group head has several notches to place your portafilter and 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 on the head permit a precise location of the portafilter which is essential for an efficient extraction.

The group head not only lets the portafilter to be inserted easily but also maintains the temperature at a constant level. It does this by cycling hot water through the brew basket, and around the portafilter, making sure that it's always at the correct temperature for extraction. It is important to remember that even a tiny differences can make the distinction between a good and excellent espresso.

The Pump

The motorized pumps in rotary espresso machines provide the nine atmospheric bar pressure needed for espresso extraction. This is different from manual piston machines that rely on levers. This pressure is generated by pumping water through a heat exchanger and then through the ground coffee.

Pumps are typically less expensive than piston-driven models, and they tend to last longer, but both types of machines may be damaged by excessive use and inadequate cleaning. Pumps are also more complex mechanically, and can add to prices of even most basic models.

Certain espresso machines remove the pump entirely and make use of steam pressure to make 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. The machines also need to continually rebuild their pressure between cups. This requires energy and time.

Many espresso machines utilize a vibration or rotary pump, with a vibrating model using a vibrating disc to create pressure and a rotary model pushing hot water through the grounds under high speed. Both machines can make excellent espresso however rotary machines tend to be quieter, more durable and less likely to fail.

The Boiler

The boiler is what makes the water warm to a temperature that is ideal to extract. The steam created will eventually reach the portafilter, which contains the espresso coffee grounds. It is then poured into the cup. The steam causes enough pressure to push the grounds of coffee through. This results in a layer crema that is then poured over. This is the hallmark of a good espresso.

There are three types of espresso machines, each with distinct pumps and brew temperature. There are different ways to control the strength of the brew and the size of the cup that can be produced by the machine.

The first espresso machines were steam-types. The first espresso machines were steam types. The coffee tasted bitter and burnt. The modern espresso machine was designed by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most popular espresso maker is a semi-automatic machine that has an electric pump. When people think of espresso machines, they think of these machines. Semi-automatic machines require you to grind and tamp the beans by yourself The pump, however, regulates the water flow and pressure. This is a great compromise between the human touch and the mechanized accuracy.

The Filter

Typically, retro espresso maker machines utilize filters to separate the grounds of coffee when they pass through the hot water. The filter is also an important element of the temperature control system, since it helps prevent the machine from overheating.

Filters also aid in flavor as it allows for a longer flowering period. This lets the beans release their nuances, and improves extraction.

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

It's in this area that the magic takes place. This is what makes espresso taste so delicious. The grouphead, often called the brewhead, is where the portafilter (the thingy you put the ground coffee in) sits when you're making espresso.

Steam-driven espresso machines use hot water that is heated inside an airtight vessel to create steam. The steam then pushes hot water into the coffee grounds under high pressure. They are less expensive and easier for the owner to maintain than pumps-driven models. They are however limited 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 years, espresso machines driven by a compressed air compressor have become increasingly popular. They use an air compressor to push hot water into the grounds and are more portable than steam-driven electric machines.