A Look Into The Future: What Will The Machine Espresso Industry Look Like In 10 Years?
A Look Into The Future: What Will The Machine Espresso Industry Look Like In 10 Years?
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How Does Machine Espresso Work?
Machine espresso employs precise pressure and amazing filter technology to make the perfect cup of coffee. How does it work exactly?
To make an espresso hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee. However, the pressure is the major difference.
The Group Head
The name implies the group head is where you place your portafilter when making espresso. It is responsible for dispersing water into the portafilter before controlling the pressure of the resulting extraction. There are a variety of types of group heads each with its distinct advantages and drawbacks. Some are designed to provide stability of temperature while others are designed to handle pre-infusion. Some are designed to control the lever. Some have a combination, like the E61. This is a popular choice among baristas as it provides a variety of benefits in a single package.
As you can see in the photo above the group head comes with numerous notches that you can place your portafilter before twisting it manually to lock it in. A gasket of rubber is situated in the notches to create a seal when you insert your portafilter. The notches on the head permit a precise positioning of the portafilter which is crucial to ensure an efficient extraction.
The group head does not just allow the portafilter to be inserted easily but also maintains the temperature at a constant level. It does this by circulating hot water through the brew pan and around the portafilter, making sure that it is always at the correct temperature to extract. It is important to note that even a slight deviation can make the difference between a good and great espresso.
The Pump
Contrary to manual piston machines which rely on a lever to pressurize water, rotating espresso machines rely upon motorized pumps to deliver the nine atmospheric bars of pressure necessary to extract espresso. This pressure is built up by pumping water through a heat exchanger and then through the ground coffee.
Pumps tend to be less expensive and last for longer than piston-driven machines. However, both kinds of machines are susceptible to degrading due to overuse and insufficient cleaning. They also add mechanical complexity that can lead to an expensive price for even the simplest models.
Some espresso machines use steam pressure instead of a pump for brewing espresso. The drawback of this is that the same boiler that produces steam also raises the temperature of the water until it reaches boiling which could lead to 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 a vibration or rotary pump, which has a vibration model using a vibrating disc to create the pressure and rotating models that push hot water through the grounds at high speed. Both machines can produce excellent espresso however rotary machines tend to be more quiet, durable and less likely to break.
The Boiler
The boiler is the part that heats water to the ideal temperature for extraction. The resulting steam is then transferred to the portafilter, which contains the ground espresso coffee and gets funnelled down into the cup. The steam generates enough pressure to push the grounds of coffee through. This results in a crema on top of the espresso. This is the hallmark of a great espresso.
There are three different types of espresso machines, each with different types of pumps and brew temperature. There are various ways in which the brew could be controlled and the size of the cup that the machine is capable of making.
The earliest espresso machines were steam-based. The earliest espresso machines were steam types. This led to the coffee tasting bitter and burnt. This is the reason why Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni developed read more the modern espresso machine.
The most popular espresso machine is a semiautomatic one with an electric pump. These are what people imagine when they think of an espresso machine. With a semi-automatic espresso machine, you have to grind the beans and then tamp them yourself but the pump provides regulated water flow and pressure. This is a great compromise between the human touch and the mechanized quality.
The Filter
Typically, espresso machines use filters that separate the grounds of coffee when they pass through the hot water. The filter is also a vital element of the machine's temperature control, since it stops overheating.
A filter also helps with flavor as it allows for the beans to flower for a longer period of time. This helps the beans to release their flavor and gives the chance for better extraction.
It is important to keep in mind that even the finest filter could result in a poor cup of coffee. The quality of the beans and the extraction process, remain crucial.
It's in this area that the magic occurs. This is what makes espresso taste so good. The grouphead (also known as the brewhead) is where you place the portafilter, which is the thingy which you put the coffee grounds into, when making espresso.
Steam-driven espresso machines use hot water that is heated inside an airtight container to create steam. The steam then pushes hot water through grounds of the coffee under pressure. They are less expensive and easier for the user to maintain than pumps-driven models. They are however limited to create the perfect conditions for brewing, as they operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.
In recent times, espresso machines powered by compressed air-pump are becoming increasingly popular. They utilize an air compressor to force hot water through the ground and are much more mobile than steam-driven electric espresso machines.