In essence, espresso coffee is produced by forcing, under pressure, very hot water through roasted and finely ground coffee beans. Compared to other methods of coffee-making, espresso usually has a thicker consistency, with a higher concentration of dissolved solids and crema (or foam). Accordingly, and as a consequence of the pressurized brewing process, the end cup of coffee contains a much higher concentration of flavours. This strong flavour base makes espresso perfect as a foundation for other coffee styles such as latte, cappuccino, macchiato, mocha and Americano. A shot of espresso is ideal for iced coffee as well, once it has been chilled down ready to add to the milk.
While it sounds simple, there are a myriad of other factors that can impact significantly on the quality of the final espresso. Starting of course with the type of coffee; where it is grown, how it is roasted, by what method and how finely it is ground, how much pressure is used to tamp the grinds and so on – all have an impact on flavour before you even put it in the machine!
For the purposes of this article, however, we will just look quickly at the basic types of espresso coffee machine for domestic, non-commercial use. Ideally it will provide some useful information for anybody looking to investigate espresso coffee machines.
The manual espresso machine: first developed in 1945 by Achille Gaggia, founder of the company that has become one of the world’s leading espresso machine manufacturers. This design uses a hand operated lever that pumps pressurized hot water through the coffee grinds. These machines are not often seen in domestic situations as they require a high level of expertise. This machine is capable of producing exceptional coffee if everything is just right.
Semi-automatic espresso machines: use an electrically powered pump rather than manual force to deliver the hot water. In most examples the user the length (time) of the shot by an activation switch or button, while solenoids and valves look after controlling pressure. Today’s semi-automatic machines allow pre-programming of these functions. Others still, provide a pre-dose function, that infuses the coffee prior to the extraction shot. The Gaggia Classic 14101 is a fine example of a highly regarded semi-automatic coffee machine, as is its sister, the Gaggia 12500 Baby Twin Espresso. Also worth considering from another world-renowned manufacturer is the Rancilio Silvia Espresso Maker.
Automatic machines: these control the amount of water passing through the coffee and hence the brewing time. This is achieved by way of flow-meters, solenoids, valves and small control circuits that automate the whole process.
In both the semi and fully automatic machines just described, the user must still grind the coffee (or purchase pre-ground coffee, as a less-preferred option), then fill the group handle (portafilter) and tamp it with the required pressure. These processes can have quite an impact on the quality of the end pour, so they are skills wanting to be learned and practiced by the home ‘barista’.
Super-automatic espresso machines: automatically grind coffee beans that are dispensed from an internal hopper, tamp it to a predetermined pressure, and manage the length of the extraction. Some models also contain automated milk frothing and dispensing devices to simplify the task even further. The main advantage of these machines is their fully automated functions. All that has to be done is to keep the machine filled with coffee beans, water and milk. These ‘all-in-one’ espresso machines often have a smaller footprint than a separate espresso machine and grinder, while they usually create less mess on the bench top also. The quality of the espresso produced is very consistent, as all the variables have been electronically controlled and accurately measured.
Readers should consider, however, that, by virtue of their complexity, super-automatic espresso machines may require more maintenance and should be serviced regularly. The lack of control over the grind and tamping pressure may also impact on coffee quality.
So, to conclude. There are a wide range of options available in the espresso coffee machine market. For those who want to control the process of extracting the perfect shot and have the time to learn how to do so through trial and error, the manual and semi-automatic machines are ideal. An advantage is that with these types of machines you can control the different styles of coffee produced.
The automatic machines manage the process very well without too much fuss, but the selection of beans, grind and tamping still allow for some hands-on involvement. While finally, the super-automatic machines look after the entire coffee making procedure – allowing you to get on and do something else.
You need to consider how many shots you need at any given time and how involved you want to get in the whole process. You may wish to consider the convenience aspect on one hand versus creative quality control on the other.