9 Things Your Parents Taught You About Machine Espresso

How Does Machine Espresso Work?

Machine espresso employs precise pressure and incredible filter technology to produce the perfect cup of coffee. How exactly does it work?

Espresso is produced by pushing 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 Head of the Group

The group head is the portafilter you put in when making espresso. It distributes water into the portafilter and controls the pressure of the extraction. There are a variety of group heads each with its own 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 combination such as the E61. This is a popular choice among baristas due to the fact that it has multiple advantages in a single package.

As you can see in the above photo the head of the group is equipped with several notches. You can place your portafilter into these notches and twist the head to lock it. There is also a gasket of rubber which is located inside the notches and helps best bean to cup espresso machine create the seal when you insert your portafilter into the machine. The notches on the head permit a precise positioning of the portafilter which is vital to ensure an even extraction.

Apart from allowing you effortlessly insert your portafilter the group head is also responsible to maintain an even temperature. This is accomplished by cycling hot water around the portafilter, and through the brew-basket, making sure the temperature is always right for extraction. This is vital, because even a few degrees can mean the difference between excellent and great espresso.

The Pump

The motorized pumps used in rotary espresso machines provide the nine atmospheric bar pressure needed to extract espresso. This differs from manually operated piston machines that employ a lever. The pressure is created by pumping water through a heat-exchanger and then through the ground coffee.

Pumps tend to be cheaper than piston-driven machines, and tend to last longer, but both types of machines may become damaged due to excessive use and poor cleaning. They also create mechanical complexity which can result in an expensive price for even the simplest models.

Certain espresso machines utilize steam pressure instead of a pump to make espresso. This could lead to over-extraction since the boiler that makes steam also warms the water to boil. These machines also have to constantly rebuild their pressure in between cups. This takes energy and time.

Many espresso machines make use of the rotary or vibration pump. A vibration model utilizes a rotating disk to generate pressure, while a Rotary model pushes hot coffee through the ground at a high speed. Both types of machine are capable of producing excellent espresso, but the rotary models are quieter and more durable than vibration pumps.

The Boiler

The boiler is the element that heats water to an ideal temperature to extract. The resultant steam then reaches the portafilter which holds the ground espresso and is then pumped into the cup. The steam creates pressure and pushes through the grounds of the coffee. This creates a foam on the top of the espresso. This is the hallmark of a great espresso.

There are three kinds of espresso makers, which differ in the type of pump they use and how hot the brew is. There are various ways in which the brew could be controlled, as well as the size of the cup that the machine can make.

The first espresso machines were steam-type. The earliest espresso machines were steam-type machines. This resulted in the coffee tasting bitter and burnt. This is the reason why Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

The most well-known espresso maker is a semiautomatic machine that has an electric pump. When people think of buy espresso machine machines, they picture these machines. Semi-automatic machines require you to grind and tamp the beans yourself however the pump controls the flow of water and pressure. This is a great compromise between the human touch and the mechanized accuracy.

The Filter

Espresso machines typically use filters that separate the coffee grounds from the hot water. The filter is also an essential part of the machine's temperature control, since it stops overheating.

Filters also aid in flavor as it allows for an extended flowering time. This lets the beans release their flavor and also allows for better extraction.

It is important to keep in mind that even the most efficient filter can make a bad cup of coffee. The quality of the beans and the extraction process are still very important.

This is where the magic happens, it's what makes an espresso really taste good. The grouphead (also known as the brewhead) is where you place the portafilter, the device that you use to put the coffee grounds into, when making small espresso machine.

Steam-driven espresso machines make use of hot water heated in an airtight container to create steam. The steam then moves hot water through the grounds of coffee under high pressure. These types of machines are typically less expensive and simpler to maintain than pump-driven models. They are however limited in their ability to create the ideal conditions for brewing since they only operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

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