This Week's Top Stories Concerning Machine Espresso

How Does Machine Espresso Work?

Machine espresso employs precise pressure and mind-blowing filter technology to create the coffee we love. But how exactly does it work?

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

The Head of the Group

As the name implies, the group head is the place you place your portafilter when making espresso. It disperses water into the portafilter and controls the pressure of the extraction. There are a variety of types of group heads, each with their particular advantages and drawbacks. Some are focused on temperature stability, whereas others on pre-infusion capabilities, and still others are designed to control the lever. Some have a combination, such as the E61. This is a popular choice among baristas as it provides a variety of advantages in a single package.

As you can see from the above photo, the group head is fitted with several notches. The portafilter is placed in these notches, then turn the head around to secure it. There is also a gasket of rubber in the notches and helps create the seal when you insert your portafilter into the machine. The notches on the head permit a precise location of the portafilter which is essential for a consistent extraction.

Aside from allowing you to easily insert your portafilter, the group head is also responsible for maintaining an even temperature. This is done by cycling hot water around the portafilter and through the brew-basket to ensure that the temperature is at the right level for extraction. This is vital, because even a few degrees can make the difference between a good and great espresso.

The Pump

Unlike manual piston machines, which rely on a lever to pressurize water, rotating espresso machines rely upon motorized pumps that provide the nine atmospheric bars of pressure that are required to extract espresso. The pressure builds up by drawing tap water from a reservoir, and pumping it through a heat exchanger prior to being shot through the ground coffee in the group head.

Pumps are typically less expensive and last longer than piston-driven machines. However, both kinds of machines can deteriorate due to excessive use and inadequate cleaning. Pumps are also more complicated mechanically, and can add to the cost of even simpler models.

Certain barista espresso coffee machine machines eliminate the pump entirely and utilize steam pressure to make espresso. The drawback of this is that the same boiler that produces steam also increases the temperature of the water to the point of boiling which can cause over-extraction. The machines must also continuously rebuild their pressure between cups. This requires energy and time.

Many espresso machines utilize the rotary or vibration pump, which is a vibration model using a rotating disc that generates the pressure and the rotary model pushing hot water through the grounds at high speed. Both types of machine can make excellent espresso, but the rotary models are quieter and more durable than vibration pumps.

The Boiler

The boiler is the part that heats water to an optimal temperature to extract. The steam that is created is then directed to the portafilter, which holds the espresso grounds. The steam is then channeled into the cup. During this process, the steam creates pressure and pushes through the grounds of the coffee. This results in a crema on the top of the mini espresso machine. This is the hallmark of a good espresso.

There are three kinds of espresso makers. They differ in the kind of pump they use and the degree of heat that the espresso is. There are also different ways in which the brew could be controlled as well as the dimensions of the cup the machine can make.

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

The most commonly used espresso maker is a semi-automatic one that has an electric pump. These are the images people have when they imagine an espresso machine. Semi-automatic machines require you to grind and tamp the beans yourself while the pump controls the flow of water and pressure. This is an excellent compromise between human touch and the mechanised consistency.

The Filter

Typically, espresso machines have a filter to separate out the coffee grounds as they pass through the hot water. The filter is also an important component of the temperature control system as it keeps the machine from overheating.

A filter also helps with flavor since it allows for the beans to flower for a longer period of time. This allows the beans to release their flavor and also allows for better extraction.

It is important to remember that even the most efficient filter can make a bad cup of coffee. The quality of the beans and the extraction process, remain vital.

This is where the magic happens, it's what makes an espresso really taste good. The grouphead (also called the brewhead) is where you put the portafilter - the thingy used to place the coffee grounds into, while making espresso.

Steam-driven espresso coffee machines uk machines use hot water that is heated inside an airtight container to create steam. The steam then pushes hot water into the grounds of the coffee under pressure. These machines are cheaper and easier for the user to maintain than pumps-driven models. They are however limited for creating the ideal conditions for brewing as they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.

In recent years, espresso machines powered by compressed air-pump are becoming increasingly popular. They use an air-compressor to force hot water through the ground, and are more mobile than steam-driven electric espresso machines.