9 Lessons Your Parents Teach You About Machine Espresso

How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and mind-blowing filter technology to create the delicious coffee we enjoy. How 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 pressure is the major difference.

The Group Head

The group head is the portafilter that you put in when making italian espresso machines. It disperses the water into the portafilter and controls the pressure of the extraction. There are many different kinds of group heads each with its particular advantages and disadvantages. Some are focused on temperature stability, whereas others on pre-infusion options, and others are designed to control the lever. There are also some that include a mix of features, such as the E61, which is considered the classic choice among many baristas due to its capacity to offer multiple benefits in one package.

As you can see from the photo above the head of the group has a number of notches. You place your portafilter in these notches and then turn the head around to secure it. A gasket of rubber is situated inside the notches, which helps create a seal when you insert your portafilter. The notches allow for precise placement of your portafilter. This is crucial to ensure an accurate extraction.

The group head not only allows the portafilter to be inserted easily however, it also keeps a constant temperature. This is achieved by cycling hot water around the portafilter, and through the brew-basket to ensure that the temperature is at the right level for extraction. It is important to note that even a slight difference can make the difference between a great and a excellent espresso.

The Pump

Motorized pumps in espresso machines that rotate provide the nine atmospheric bar pressure that is required to extract espresso. This is different from manually operated piston machines that employ levers. The pressure builds up by drawing tap water from a reservoir and pumping it through a heat exchanger prior being pumped through the ground coffee inside the group head.

Pumps tend to be cheaper than piston-driven machines and tend to last longer. However, both types of machine can become damaged due to excessive use and poor cleaning. They also increase the complexity of mechanical systems that can lead to an expensive price for even the most basic models.

Certain espresso machines eliminate the pump completely and instead make use of steam pressure to make espresso. The downside is that the boiler that produces steam also raises the temperature of the water to boiling and can result in excessive extraction. These machines also have to continuously rebuild their pressure between cups. This takes energy and time.

A large majority of espresso machines employ an rotary or a vibration pump. A vibration model makes use of a rotating disk to generate pressure, whereas the rotary model pushes hot water through the ground at high speed. Both machines produce great espresso however rotary machines tend to be more stable, quieter and less likely to break down.

The Boiler

The boiler is the element that heats water to an ideal temperature for extraction. The steam that is created is then directed to the portafilter, which is the container that holds the espresso coffee grounds. It is then pumped into the cup. During this process the steam is able to create enough pressure to push the coffee grounds through. This creates a crema on top of the espresso. This is one of the hallmarks of a good espresso.

There are three kinds of espresso makers. They differ in the type of pump they employ and how hot the brew is. There are different ways to control the brew and the size of the cup that can be produced by the machine.

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

The most common espresso maker is a semiautomatic machine with an electric pump. These are the things people think of when they think of an espresso maker. Semi-automatic machines require you to grind and tamp your beans yourself however the pump controls the flow of water and pressure. This is a great compromise between the human touch and the mechanized quality.

The Filter

Espresso machines typically have filters that separate the grounds of coffee from hot water. The filter is also a vital element of the machine's temperature control, as it prevents overheating.

A filter can also help with flavor because it allows for a longer flowering period. This allows beans to release their nuances and gives an opportunity for a better extraction.

However, it is important to keep in mind that even a great filter can make a terrible cup of coffee as the quality of the beans and extraction is still crucial.

This is where the magic happens. It's what makes espresso taste good. The grouphead (also known as the brewhead) is where you put the portafilter, which is the thingy used to place the coffee grounds into, while making espresso coffee machine with milk frother.

In the steam-driven espresso machine hot water is heated in an airtight tank to create steam, which is then pushed through the grounds under high pressure. These types of machines are generally less expensive and easier to maintain than pumps-driven models. However, they are not as efficient in their ability to provide the ideal conditions for brewing as they only operate at 1-1.5 bars of pressure. The perfect shot requires 9-10 bars.

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