How to make an espresso
Think of any type of specialty coffee, a cappuccino, a mocha, or a flat white. What do they all have in common? The base. All of them are made using a shot or two of dark, rich espresso coffee. A great espresso is the foundation of all good coffee. That’s why knowing how to make a good espresso is vital for any true coffee lover. So how do you do you make the perfect espresso?
The vital ingredients
There are a number of vital ingredients to making an espresso: the roast; the grind; the amount of coffee; the water pressure; the water temperature; and the tamping. Each has its part to play in producing the rich, crema-topped liquid necessary for your favourite coffee. But don’t worry, it’s not as complicated as it sounds!
As espresso is a dark, richly flavoured coffee, it requires dark-roasted beans. There’s a scientific reason for this: dark-roasted beans have been roasted for longer than their lighter counterparts. When beans are roasted, they become more porous, allowing for the taste to be extracted. The longer and darker the roast, the more porous the beans are, and the easier it is to extract the flavor compounds, leading to a stronger coffee.
Espresso coffee requires a fine grind. The finer the grind, the longer it takes the water to pass through the granules. This increases the pressure necessary to push the water through the beans, something which we’ll discuss in a moment. However, you don’t want a grind that’s too fine, as that can lead to a bitter, over-extracted coffee.
The ideal Italian-style double espresso requires 14g of good quality coffee to produce 30ml of perfect caffeine nectar.
Water pressure is key to a good espresso. Not enough pressure, and the water will pass through the beans too slowly, leading to a bitter, over-extracted coffee. Too quickly, and you’ll end up with a weak, under-extracted liquid that’s not going to hit that caffeine spot. It should take around thirty seconds for the water to pass through the coffee grinds.
Ideally, you want pressure of around nine bar, that’s nine times atmospheric pressure at sea level, or 130lbs of pressure per square inch. That’s a lot of pressure!
Water temperature is the final component in making a great espresso. Too cold, and you won’t extract the flavour fully. Too hot, and you’ll scald the beans, leading to a bitter taste. The ideal temperature is 185℉ or 96℃.
Tamping is the process of compressing the coffee in the portafilter to create a ‘puck’-like disc of coffee. Achieving the right amount of compression is another key component in creating the perfect espresso. Too compressed, and the water will travel through too slowly causing, yes, over-extracted and bitter coffee. Not compressed enough, and it’ll brew too quickly.
Uneven compressing also causes problems, as the water will seek the easiest path through the grinds, leading to a mix of under- and over-extraction, with the potential scalding of some of the beans.
And there it is! All of the factors you need to consider when brewing the espresso that’ll make your perfect coffee.