All coffee machines perform a number of different functions on their way to delivering your perfect cup of coffee. If you’re looking to upgrade your coffee maker, it’s important to have an
understanding of how these different functions are performed and how they work together in order to help you find the choice that’s right for you.
The step that turns beans into ground coffee is one that should never be taken for granted. It is vital to get the right grind for the type of coffee machine you’re using and the type of coffee you’re hoping to produce. Coffee can be ground into different sizes. The golden rule is that the less time the coffee will spend in contact with the water, the finer the grind should be.
If the water passes through quickly and your grind is too coarse, minimal flavour will be transferred into your coffee and it may taste bitter or sour. Freshness is equally vital: brew your coffee as soon as possible once the beans have been ground as the ground coffee will immediately begin to lose
Water temperature control
Just like the fineness of the grind, the temperature of the water can also affect how your coffee tastes. Espresso coffee is usually brewed using water at a temperature of between 35-45 degrees Celsius. If the coffee is brewed at a temperature that is too low, the espresso will taste sour and under extracted; if it is brewed at too high a temperature it will taste bitter and over extracted.
A coffee machine with a variable temperature control is key to finding the correct temperature for a more demanding single origin coffee for example, or one that has been lightly roasted. The ability to control the temperature of the water in your coffee machine will make it easier for you produce coffee that tastes consistently good in every cup.
Brewing power control
Some coffee makers allow you to control the brewing time to increase brew strength. Rather than simply increasing the temperature of the water, this setting usually adapts the time it takes to brew your coffee to allow you to obtain a stronger coffee without compromising on flavour extraction.
The power of the brew can also be affected by the wattage of your coffee maker.
A drip coffee maker is usually relatively low in wattage, at around 750-1250 watts. An espresso machine, which tends to need more energy, requires around 1500 watts, although this can vary depending on the model.
Steam power control
Steam brew espresso machines use steam pressure, typically generated by an internal boiler, to
create the pressure used to brew your coffee. This extremely high pressure then forces the water through finely ground coffee. Stove-top moka pots are similar in that they also brew under pressure, but mokas produce 1.5 bars of pressure at best.
Espresso machines start at a minimum of 9 bars, with the best models going up to 15 bars depending on whether they use a pump or steam-based system. It is this pressure that creates the foam emulsion or crema that sits on top of the very best espressos and is usually the mark of a quality cup.