Nine Things That Your Parent Taught You About Machine Espresso

How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and amazing filter technology to make the perfect cup of coffee. But how exactly does it work?

To make espresso, hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee but the key difference is in the pressure.

The Group Head

The group head is the portafilter that you put in when making espresso. It disperses water in the portafilter, and regulates the pressure of extraction. There are a variety of group heads, each with its own advantages and disadvantages. Some are designed to provide stability of temperature while others are built to handle pre-infusion. Others are made to control the lever. There are even some that include a mix of features, such as the E61, which is the classic choice among many baristas because of its ability to provide multiple benefits in one package.

As you can see in the above image the group head comes with numerous notches that you can put your portafilter, then twist it manually to secure it. A gasket made of rubber is placed in the notches to create a seal when you insert your portafilter. The notches on the head permit an exact placement of the portafilter, which is crucial for an even extraction.

The group head is not just able to allow you to insert your portafilter easily however it also keeps the temperature at a constant level. This is done by cycling hot water around the portafilter and through the brew-basket, ensuring that the temperature is at the right level to extract the coffee. It is important to remember that even a few degree difference can make the difference between a decent and a excellent espresso maker barista.

The Pump

The motorized pumps that are used in espresso machines rotary provide nine atmospheric bar pressure that is required for espresso extraction. This is different from manual piston machines espresso machines which use a lever. The pressure builds up by drawing tap water from a reservoir and pumping it through a heat exchanger before being pushed through the ground coffee inside the group head.

Pumps are generally less expensive than piston-driven machines, and they tend to last longer, but both types of machines may get damaged through overuse and lack of cleaning. Pumps are also more complicated mechanically, and can add to the cost of even the simplest models.

Certain espresso machines remove the pump completely and employ steam pressure to create espresso. This can cause over-extraction because the boiler that makes steam also heats the water to boil. In addition these machines are often required to restore their pressure between cups, which takes time and energy.

A majority of espresso machines use an rotary or vibrating pump, which has a vibration model using a vibrating disc that generates the pressure and rotating models that push hot water through the grounds at high speed. Both machines produce great espresso but rotary machines are quieter, more durable and less likely to break down.

The Boiler

The boiler is what is used to heat the water to the perfect temperature for extraction. The resulting steam is then transferred to the portafilter, which contains the ground espresso coffee, and is then pumped down into the cup. During this process the steam causes enough pressure to push the coffee grounds through. This results in a layer of crema on top. This is one of the main characteristics of a good espresso.

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

The earliest espresso machines were steam-based. The first espresso machines were steam-type machines. This resulted in the coffee tasting bitter and burnt. This is the reason why Milanese producers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.

The most common espresso machine is a semiautomatic that has an electric pump. These are what people imagine when they imagine an espresso machine. Semi-automatic machines require you to grind and tamp your beans yourself The pump, however, regulates the flow of water and pressure. This is a perfect compromise between human control and mechanized consistency.

The Filter

Typically, espresso machines use filters that separate the grounds of coffee as they move through the hot water. The filter is also an essential part of the machine's temperature control, since it stops overheating.

It also enhances flavor, as it allows for a longer bloom time. This helps the beans to release their flavor and gives an opportunity for better extraction.

It is important to keep in mind that even the most efficient filter could result in a poor cup of coffee. The quality of the beans, and the extraction process, are still very important.

It's here that the magic takes place. This is the reason why espresso tastes so delicious. The grouphead (also called the brewhead) is where you put the portafilter, the thingy which you put the grounds of your coffee into while making espresso.

Steam-driven espresso machines make use of hot water heated in an airtight vessel to create steam. The steam then pushes hot water through the coffee grounds under high pressure. They are less expensive and easier 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 ideal shot requires 9-10 bars.

In recent years, compressed-air-pump-driven espresso machines espresso machines have been gaining popularity. They make use of an air compressor to force hot water through the ground, and are more mobile than steam-driven electric espresso machines.