An Espresso Machine is the true way to brew
There are several varieties of Espresso machine, designed for a multitude of applications and settings, be they for the small scale home drinker, or the large commercial kitchen. Numerous manufacturers have developed large ranges of highly reliable equipment that ensures the customer an excellent cup of coffee, quickly and with delicious results.
Before launching into a review of espresso machines there are some basic technological terminologies that should be discussed before a reasonable understanding of the capacities and capabilities of the espresso machine can be truly understood.
The first thing to introduce is the extraction mechanism. While some coffee makers operate on drip or filter principles, the point of Espresso is that it is an expressed coffee. This is a slightly unclear statement, and the ambiguity arises out of the word express. As the extraction occurs at Eighty eight degrees centigrade, below the boiling point of water utilizing water pressurized in a boiler, there is an expression of the water through the ground coffee that results in a very concentrated coffee being produced.
It should be noted that while it is also a very quick method for making coffee, it is not necessarily an express form. The espresso, Italian for express, is intended to define a type of coffee made through the use of heated water being forced through a bed of ground coffee, NOT for a coffee that was made fast. You should be clear to use the word espresso, with an ‘ess’ sound at the start, otherwise anyone with a clue will look at you and think you are a dolt.
The coffee is ground into a group, which is a basket with a filter in the bottom, attached to a handle that can be locked into the machine below the water valve. There are often attachments on the underside of a group that allow the coffee extract to be channeled into one or two cups. The group is usually fitted with either a single or a double filter, and the filter can be changed. This allows for a variety of coffee strengths to be produced at any one time, with the same basic principle of pressurized extraction.
Many espresso machines also incorporate steaming wands to allow milk to be frothed to a micro-foam, allowing for the creation of latte’s and flat milk based coffee drinks. Though these are now standard on many machines, the true espresso is actually just the concentrated shot of coffee liquor extracted in the initial stage. A single shot is 7ml, while a standard double is 14ml. This may seem small, but with all that coffee essence suspended in such a tiny amount of water, a double shot of espresso can kick start even the slowest of days.
Beyond the steam wand, the group and the filters, lies a network of piping connected to pumps and the boiler. The boiler is often powered by electricity, though it can also be gas fired. This is the powerhouse of the machine, providing hot, pressurized water, steam, and hot water for tea and hot chocolate also. In a commercial machine the boiler can be an energy hungry thing, with many boiler types requiring several kilowatts of electricity every hour. These are the basic parts of the espresso machine.