9 Lessons Your Parents Taught You About Machine Espresso

How Does Machine Espresso Work?

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

Espresso is made by forcing hot water under pressure through finely ground coffee. The process is similar to making drip coffee but the difference is in the pressure.

The Group Head

The group head is the portafilter that is inserted when you are making espresso. It distributes water into the portafilter, and then regulates the pressure of the extraction. There are various kinds of group head each with its distinct advantages and drawbacks. Some are designed to provide stability in temperature, while others are built to handle pre-infusion. Some are designed to control the lever. Some include a mix of features, like the E61 one, which is the standard choice for many baristas due to its capacity to provide multiple benefits in one package.

As you can see in the image above, the group head has many notches in which you can place your portafilter before twisting it manually to secure it. There is also a gasket of rubber that resides inside the notches and helps create an airtight seal when you insert your portafilter into the machine. The notches permit an exact placement of the portafilter. This is essential for an even extraction.

In addition to allowing you to 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 Machine espresso through the brew-basket, making sure that the temperature is always at the right level for extraction. This is important because just a few degrees could make the difference between a good and excellent espresso.

The Pump

Motorized pumps in rotary espresso machines provide the nine atmospheric bar pressure required for espresso extraction. This differs from manual piston machines which use levers. The pressure builds up by drawing tap water from a reservoir, and pumping it through a heat exchanger before being shot through the ground coffee inside the group head.

Pumps are generally less expensive and last for machine espresso longer than piston-driven machines. However, both kinds of machines may degrade due to excessive use and insufficient cleaning. Pumps are also more complicated mechanically, which can raise the price of even the simplest models.

Some espresso machines do away with the pump completely and instead make use of steam pressure to make espresso. This can lead to over-extraction as the boiler that produces steam also heats the water to boil. These machines also have to constantly rebuild their pressure between cups. This requires energy and time.

Many espresso machines utilize a vibration or rotary pump, with a vibration model using a rotating disc to create the pressure, and the rotary model pushing hot water through the grounds at high speed. Both models can produce an excellent espresso, however Rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler is the element which heats the water to the optimal temperature to extract. The resulting steam is then transferred to the portafilter, which contains the ground espresso coffee, and is then funneled down into the cup. During this process the steam generates enough pressure to push the coffee grounds through. This creates a crema on top of the espresso. This is one of the main characteristics of a great espresso.

There are three distinct types of espresso machines, each having different pumps and the temperature of the brew. There are different ways that the brew can be controlled, as well as the size of the cup that the machine is capable of making.

The first espresso machines were steam type. The earliest espresso machines were steam types. The coffee tasted bitter and burnt. The modern espresso machine was developed by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.

The most popular espresso machine is a semiautomatic with an electric pump. This is what people envision when they imagine an espresso machine. With a semi-automatic machine you have to grind the beans and then tamp them by hand. However, the pump controls the flow of water and pressure. This is an excellent compromise between human touch and the mechanised consistency.

The Filter

Typically, uk espresso machine machines use a filter to separate out the coffee grounds as they pass through the hot water. The filter is also an essential component of the machine's temperature control, since it helps to prevent overheating.

A filter also improves flavor since it allows for the beans to flower for a longer period of time. This allows the beans to let their nuances out, and allows for better extraction.

However, it is important to remember that even a good filter can make a terrible cup of coffee, because the quality of the beans and extraction is still important.

This is where the magic happens. It's what makes an espresso really taste great. The grouphead, often referred to as the brew head, is where the portafilter (the thing you put the ground coffee into) is placed when you're making espresso.

Steam-driven espresso machines use hot water heated in an airtight container to create steam. The steam then pushes hot water into the grounds of coffee under high pressure. These machines are cheaper and easier for the owner to maintain than pumps-driven models. However, they are limited in their capacity to create the perfect conditions for brewing, since they are only operating at 1-1.5 bars of pressure, while the perfect shot requires 9-10 bar.

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