10 Tell-Tale Symptoms You Must Know To Look For A New Machine Espresso
10 Tell-Tale Symptoms You Must Know To Look For A New Machine Espresso
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How Does Machine Espresso Work?
Machine espresso makes use of precise pressure and incredible filter technology to produce the delicious coffee we enjoy. What exactly does it work?
Espresso is produced by pushing hot water at high pressure through finely-ground coffee. The process is similar to that of making drip coffee. However, the pressure is the major difference.
The Head of the Group
The group head is the portafilter that you place in the espresso maker when making it. It is responsible for dispersing the water into the portafilter, and controlling the pressure that results from the extraction. There are several different types of group head each with its distinct advantages and drawbacks. Some are designed for the stability of temperature while some are designed to handle pre-infusion. Some are designed to control the lever. There are some that contain a variety of features, such as the E61 one, which is the standard choice for many baristas due to its capacity to provide multiple benefits in one package.
As you can see in the photo above the head of the group has a number of notches. You place your portafilter inside these notches, and then twist the head to secure it. A gasket of rubber is situated in the notches to create a seal as you insert your portafilter. The notches permit precise placement of the portafilter. This is crucial for an efficient extraction.
Aside from allowing you to effortlessly insert your portafilter the group head is responsible to maintain an even temperature. It does this by cycling hot water through the brew basket, and around the portafilter, making sure that it's always at the right temperature to extract. This is crucial, since even a few degrees can make the difference between a good and excellent espresso.
The Pump
The motorized pumps that are used in rotary espresso machines provide the nine atmospheric bar pressure needed to extract espresso. This differs from manually operated piston machines that employ levers. The pressure builds by removing tap water from a reservoir, and pumping it through a heat exchanger prior to being shot through the ground coffee in the group head.
Pumps are generally less expensive than piston-driven machines, and they tend to last longer. However, both types of machines could be damaged by excessive use and inadequate cleaning. Pumps are also more complicated mechanically, and can add to the price of even the most basic models.
Some espresso machines remove the pump completely and instead use steam pressure to brew espresso. The downside is that the same boiler that produces steam also raises the temperature of the water until it reaches boiling, which can lead to over-extraction. The machines must also continuously rebuild their pressure between cups. This takes energy and time.
Many espresso click here machines employ an rotary or vibrating pump, with a vibration model using a rotating disc to generate the pressure, and rotating models that push hot water through the grounds at high speed. Both models are capable of producing excellent espresso, however rotary machines are quieter and more durable than vibration pumps.
The Boiler
The boiler is what heats the water to the right temperature for extraction. The resultant steam then reaches the portafilter that contains the ground espresso and is then pumped into the cup. The steam is able to create enough pressure to push the coffee grounds through. This results in a layer of crema that is then poured over. This is a hallmark of a good espresso.
There are three kinds of espresso makers, which differ in the kind of pump they use and how hot the brew is. There are a variety of ways to control the brew and the size of cup that can be produced by the machine.
The first espresso machines were steam-types. They used a single boiler to make both brew and steam, but the pressure they could produce was not very high - two bars of atmospheric pressure at the most. The coffee tasted bitter and burned. This is why the Milanese producers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.
The most well-known espresso machine is a semiautomatic model with an electric pump. These are the images people have when they think of an espresso maker. With a semi-automatic espresso machine, you need to grind the beans and then tamp them by hand, 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 employ a filter to separate out the coffee grounds as they pass through the hot water. The filter is also an important component of the temperature control system because it stops the machine from overheating.
A filter also helps with flavor since it allows for a longer flowering phase. This allows the beans to let their nuances out, and improves extraction.
It is important to remember that even the finest filter can make a bad cup of coffee. The quality of the beans, as well as the extraction, remain crucial.
It's here that the magic occurs. This is the reason why espresso tastes so good. The grouphead, sometimes called the brew head, is the place where the portafilter (the device you put the coffee grounds into) sits when you're making espresso.
In a steam-driven espresso machine hot water is heated in an airtight container to create steam. Steam is then pushed through the grounds at high pressure. These types of machines are usually less expensive and easier to maintain than pump-driven models. They are however limited in their ability to create the ideal conditions for brewing as they only operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.
In recent years, espresso machines driven by a compressed air compressor have become increasingly popular. They use an air compressor to push hot water through grounds and are more portable than steam-driven electric machines.