How Does Machine Espresso Work?

Machine espresso makes use of precise pressure and incredible filter technology to produce the coffee we love. What exactly is it that makes it work?

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

The Group Head

The group head is the portafilter that is inserted when you are making espresso. It disperses water into the portafilter, and then regulates the pressure during the extraction. There are many different types of group heads each with its own advantages and drawbacks. Some are specifically designed for the stability of temperature while some are built to handle pre-infusion. Others are built to control the lever. Some include a combination such as the E61. This is a preferred choice for baristas because it offers multiple benefits in one package.

As you can see in the photo above, the group head has numerous notches that you can place your portafilter and then twist it by hand to lock it in. A gasket made of rubber is placed inside the notches to help create a seal while you insert your portafilter. The notches on the head allow for an exact placement of the portafilter, which is necessary for a consistent extraction.

The group head does not just allow you to insert your portafilter easily but also maintains an even temperature. It does this by cycling hot water through the brew basket and around the portafilter, machine Espresso ensuring that it is always at the correct temperature to extract. It is important to realize that even a tiny deviation can make the difference between a decent and a great espresso.

The Pump

In contrast to manual piston machines which use a lever to pressurize water, rotary espresso machines rely on motorized pumps that provide the nine atmospheric bars of pressure that are required for espresso extraction. The pressure builds by removing tap water from a reservoir, and pumping it through a heat exchanger prior it is shot through the ground coffee in the group head.

Pumps tend to be more affordable and last longer than piston-driven machines. However, both types of machines are susceptible to degrading due to excessive use and insufficient cleaning. Pumps are also more complicated mechanically, which could increase the cost of even the simplest models.

Some espresso machines remove the pump completely and utilize steam pressure to make espresso. The downside is that the boiler that produces steam also raises the temperature of water until it reaches boiling which can cause over-extraction. Additionally, these machines frequently have to restore their pressure between cups, which takes time and energy.

Many espresso machines utilize an rotary or vibrating pump, which has a vibration model that uses a vibrating disc that generates the pressure, and the rotary model pushing hot water through the grounds at high speed. Both machines produce great espresso, but rotary machines are more quiet, durable and less likely to break down.

The Boiler

The boiler is what makes the water warm to the right temperature to extract. The resulting steam reaches the portafilter containing the ground espresso coffee, and gets funnelled down into the cup. The steam is able to create enough pressure to push the grounds of the coffee through. This creates a crema on top of the espresso. This is a hallmark of a good espresso.

There are three kinds of espresso machines, each having different types of pumps and the temperature of the brew. There are various ways to control the amount of brew, as well as the size of the cup that can be made by the machine.

The earliest espresso machines were steam-based. The earliest espresso machines were steam types. The coffee tasted bitter and burnt. This is the reason Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.

The most common espresso coffee maker maker is a semi-automatic espresso machine machine with 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, but the pump regulates the water flow and pressure. This is a great compromise between the human touch and the mechanized accuracy.

The Filter

Espresso machines usually have a filter that separates the grounds of the coffee and espresso maker from the hot water. The filter is also a vital part of the machine's temperature control, since it stops overheating.

It also aids in flavor, since a filter allows for a more prolonged bloom phase. This allows the beans to let their nuances out and Machine Espresso provides an opportunity for better extraction.

It is important to keep in mind that even the best filter can make a bad cup of coffee. The quality of the beans, and the extraction, remain vital.

It's in this area that the magic occurs. This is the reason why espresso tastes so good. The grouphead, sometimes called the brew head, is where the portafilter (the device you put the coffee grounds into) is placed when you're making espresso.

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

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