How Does Machine Espresso Work?

Machine best espresso machine under 500 utilizes precise pressure and mind-blowing filter technology to make the delicious coffee we enjoy. But how exactly does it work?

Espresso is made by pushing hot water under pressure through finely ground coffee. The process is similar to that of making drip coffee. However, the pressure is the main difference.

The Group Head

As the name suggests, the group head is the place you place your portafilter when making espresso. It is responsible for dispersing water into the portafilter and controlling the pressure of the resulting extraction. There are many different types of group heads each with its own advantages and drawbacks. Some focus on temperature stability, others on pre-infusion features, and others are designed to control the lever. Some come with a combination of both, such as the E61. This is a favorite among baristas as it provides a variety of advantages in one package.

As you can see from the above photo the group head is fitted with several notches. You place your portafilter into these notches and turn the head around to secure it. There is also a gasket of rubber which is located inside the notches and helps create an airtight seal after inserting your portafilter into the machine. The notches permit precise placement of the portafilter. This is crucial to ensure an efficient extraction.

The group head does not just allow you to insert your portafilter easily however, it also keeps an even temperature. This is done by cycling hot water around the portafilter, and through the brew-basket, making sure that the temperature is at the right level for extraction. This is crucial, since even a best small espresso machine difference in temperature can make the difference between excellent and great espresso.

The Pump

Motorized pumps in espresso machines rotary provide nine atmospheric bar pressure that is required for espresso extraction. This is different from manually operated piston machines that employ levers. The pressure is built by pumping water through a heat-exchanger and then through the ground coffee.

Pumps are typically cheaper and last longer than piston-driven machines. However, both types of machines can degrade because of excessive use and inadequate cleaning. Pumps are also more complex mechanically, and can add to the cost of even the simpler models.

Certain espresso machines do away with the pump completely and instead use steam pressure to brew espresso. The disadvantage of this is that the same boiler that produces steam also increases the temperature of the water to boiling which can cause over-extraction. The machines also need to constantly rebuild their pressure in between cups. This requires energy and time.

Many espresso machines make use of the rotary or vibration pump. A vibration model makes use of the vibrating disk to create pressure, while a rotary model pushes hot water through the ground at high speed. Both models can make excellent espresso, but the rotary pumps are quieter, and more durable than vibration pumps.

The Boiler

The boiler makes the water warm to the ideal temperature to extract. The resulting steam reaches the portafilter which holds the ground espresso coffee and is then pumped down into the cup. During this process the steam generates enough pressure to push the grounds of the coffee through. This results in a layer of crema that is then poured over. This is one of the main characteristics of a great espresso.

There are three kinds of espresso makers, which differ in the type of pump they employ and the degree of heat that the espresso is. There are different ways that the brew can be controlled and the size of the cup the machine can produce.

The first espresso machines were steam-type. They had a single dual boiler espresso machine to make both steam and brew, however the pressure they were able to create was minimal - two bars of atmospheric pressure maximum. The coffee tasted bitter and burned. This is why the Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.

The most popular espresso machine is a semiautomatic that has an electric pump. This is what people envision when they think of an espresso machine. With a semi-automatic espresso machine, you have to grind the beans and tamp them yourself but the pump controls the flow of water and pressure. This is a great compromise between the human touch and the mechanised quality espresso machine.

The Filter

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

It also enhances flavor, as it can allow for a longer bloom phase. This allows the beans to let their nuances out, and also allows for better extraction.

However, it is important to remember that even a top filter can result in a poor cup of best coffee espresso machine, as 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, sometimes referred to as the brew head, is where the portafilter (the device you put the ground coffee into) is placed when making espresso.

Steam-driven espresso machines make use of hot water that is heated inside an airtight container to make steam. The steam then moves hot water through the grounds of coffee at high pressure. These machines are less expensive and are easier for the user to maintain than pumps-driven models. However, they are limited in their ability to produce the perfect conditions for brewing, because they operate at 1-1.5 bars of pressure. While the perfect shot requires 9-10 bars.

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