Essentially all coffee machines work in the same way. Water goes in, coffee goes in, water is boiled, water filters through coffee grinds picking up coffee oil on the way and lovely black frothy liquid flows into the waiting cup.
There are, however, many variables in the coffee making process. The temperature of the water, the pressure of the steam, the fineness of the ground coffee and how tightly the coffee is packed are just a few. The skilled barista controls all of these variables to produce the best coffee he or she can.
Types of Coffee Machine
There are four basic types of machine currently used by the commercial market.Manual Machines
Manual machines are seldom used and when they are it is by the true coffee purist. Manual machines take real skill to use as the correct pressure is maintained by a lever operated by the barista. These are the creme de la creme of commercial coffee machines and produce a far superior coffee to any on the mass market - a not to be missed experience for the coffee gourmet.
The pressure is controlled automatically in semi-automatic machines but water flow and other operations are still manually controlled and require skill to use properly. Again, if you can find coffee produced in this way, it is an experience to be savored.Automatic Machines
These are the most commonly used machines on the commercial market. They operate in a similar way to the semi-automatic machines but with the addition of buttons to control water flow.
While still requiring skill to use, these machines leave the barista one less thing to think about, allowing them to be able to focus more on the customer (or the flow of customers) as well as ensuring that the people they serve receive the kind of coffee experience that will have them returning to their establishment time after time.Super-Automatic Machines
These are the next generation of coffee machine. They do everything except wipe the barista's fevered brow.
These machines require little to no skill to operate and, while they do not deliver the best coffee, they do provide consistent results every time.
What Does a Commercial Coffee Machine Consist of?
In simple terms, any espresso machine consists of a boiler, a group-head and the portafilter.
The boiler, which is fed from the water mains in commercial systems, is kept half-full, allowing steam to build up and keep the machine at the correct pressure.
The group-head consists of a variable number of gravity fed nozzles connected to a pipe which runs through the boiler from the mains.
This allows fresh water to be delivered hot to the filters at the correct rate to drip through and infuse with the coffee oil, thereby creating the delicious beverage that we all love so much.
The steam, meanwhile, is directed through a separate jet to heat the milk for cappuccinos and lattes, and, as we have all observed, while waiting patiently (or not) for our particular choice of coffee, the filters are freshly filled and carefully tamped down for each serving.
Of course, as already mentioned, any machine is only as good as its operator. At the heart of all commercial coffee makers is the barista, and for a machine to operate with maximum efficiency, he/she must understand how it works, how to keep it clean and well maintained, and how to use it properly to ensure optimal coffee making each and every time.
They need to understand that if they do not drain and refill the boiler regularly limescale will build up hindering proper conduction and stopping the coffee being properly brewed, or that if they allow the filters to become clogged, the coffee will not flow as it should, again hindering optimal coffee production.
These are just two of the issues that can arise and the importance of proper training to ensure that these and other problems do not occur cannot be stressed enough.
Naturally, as far as the customer is concerned, the barista is part of the machine, and given the right circumstances and sufficient time, much of the pleasure comes from watching the skill and elan of the operation.
Even the task of filling, tapping down, and firming the grinds can become a performance, and as for wiping down the steam jet - well!