9 Lessons Your Parents Teach 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. What exactly does it work?

Espresso is created by forcing hot water under high pressure through finely-ground coffee. The process is similar to making drip coffee however the main difference lies in the pressure.

The Group Head

The group head is the portafilter you place in the espresso maker when making it. It disperses water in the portafilter, and then regulates the pressure of the extraction. There are various kinds of group head each with its distinct advantages and disadvantages. Some are designed for temperature stability while others are specifically designed to handle pre-infusion. Some are designed to control the lever. Some come with a combination of both, like the E61. This is a favorite among baristas due to the fact that it has multiple benefits in a single package.

As you can see from the image above the group head is equipped with several notches. You can place your portafilter in these notches, then turn the head around to secure it. A gasket of rubber is situated in the notches to create a seal as you insert your portafilter. The notches on the head permit a precise positioning of the portafilter which is crucial to ensure a consistent extraction.

The group head not only allows you to put in your portafilter easily however, it also keeps the same temperature. This is achieved by cycling hot water around the portafilter, and through the brew-basket to ensure that the temperature is constant to extract the coffee. This is important because just a few degrees could make the difference between a excellent and great espresso.

The Pump

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

Pumps are typically cheaper and last longer than piston-driven machines. However, both kinds of machines can deteriorate due to overuse and insufficient cleaning. Pumps are also more complex mechanically, which could increase prices of even most basic models.

Some espresso machines eliminate the pump entirely and make use of steam pressure to make espresso. This could lead to over-extraction since the boiler that makes steam also heats the water to boil. Additionally, these machines frequently have to rebuild their pressure between cups, which takes time and energy.

Many espresso machines make use of either a vibration or rotary pump. A vibration model employs the vibrating disk to create pressure, while a rotary model pushes hot water through the ground at a high speed. Both machines produce great espresso, but rotary machines are more quiet, durable and less likely to fail.

The Boiler

The boiler heats the water to a temperature that is ideal to extract. The resulting steam is then transferred to the portafilter, which contains the ground espresso coffee, and gets funnelled down into the cup. The steam causes enough pressure to push the grounds of coffee through. This results in a whipped-up top of the espresso. This is a hallmark of a great espresso.

There are three types of espresso makers. They differ in the type of pump they employ and how hot the brew is. There are also different ways that the brew may be controlled and the size of the cup that the maker can create.

The first espresso machines were steam-type. They had only one boiler to make both brew and steam, however, the pressure they could produce was very low - just two bars of atmospheric pressure maximum. This led to the coffee tasting burnt and bitter. The modern espresso machine was designed by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.

The most well-known espresso machine is a semiautomatic with an electric pump. This is what people envision when they imagine an espresso machine. Semi-automatic machines require you to grind and tamp the beans on your own however the pump controls the flow of water and pressure. This is a great solution that combines human control with mechanized consistency.

The Filter

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

It also enhances flavor, since a filter lets you enjoy a longer bloom phase. This allows the beans to release their flavors, and allows for a better extraction.

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

It's here that the magic happens. This is what makes espresso taste so good. The grouphead (also known as the brewhead) is where you place the portafilter - the thingy used to place the coffee grounds in, while making espresso coffee machine home.

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

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