"Coffee is a pleasure, if it is not good, what pleasure is it?" Said Nino Manfredi in a well-known spot in the 1980s. Very true, although many claim to sip one of the most popular, analyzed and discussed drinks in the world, just to stay awake.

Thanks to the increase in coffee culture, the spread of specialty coffees and the creation of dedicated events, in recent times this drink has been increasingly talked about. We then asked Massimiliano Marchesi (coffee expert and trainer) what are the essential characteristics of a good espresso.

«Harmonious, like all the foods we taste. The set of aromas must be balanced, as in an orchestra: in the absence of olfactory or tasting sensations that dominate the others ". If a coffee is balanced, first of all, it is not necessary to add sugar (a separate discussion would deserve the use of milk). Why add something to an already perfect drink? Usually (and sometimes unconsciously) to correct a defect: too much bitterness, a hint of burning or excessive body (when it is said that it is too strong). A good variety or blend, extracted optimally, therefore does not require the addition of sugar due to its characteristics: it is already an excellent coffee thanks to its natural sweetness. Having said that, we also know that the Arabica and Robusta varieties have specific characteristics that bring particular notes of body and aroma to the mixture. The former is known as the best species of coffee, however there are varieties of poor quality Arabica and, conversely, very valuable varieties of Robusta.

Arabica and robust

Arabica, which represents 70% of world production, is grown in the mountains above 1000 meters in more than 70 countries in the tropical belt and is low in caffeine. It is a variety more sensitive to atmospheric agents and parasites characterized by sweetness, acidity, fruity and floral notes that depend on the territory, exactly as for wine.
The Robusta grows in the plains or hills below 800 meters. It is a more resistant variety also to insects (which often attack the plant that uses them as pollinators) and lives in a more aggressive ecosystem from which it defends itself by producing more caffeine, contained in every part of the plant: leaves, fruits, flowers. On average it contains twice as much caffeine as Arabica.

«Another fundamental element is the cream. That must be compact, uniform and composed of very fine bubbles, since it is an emulsion of coffee fats that is formed thanks to the pressure generated during extraction ", explains Marchesi. The color and consistency of the cream depend on the variety and roasting, so it can vary from a lighter color, when the roasting is shorter and / or at a more moderate temperature (in jargon it is said to be clear), to a darker color in coffees roasted at high temperature and / or for a longer time.

The Robusta allows you to obtain a more voluminous cream even if it is sometimes less persistent as it is more airy. A "separating" cream is an indication of a badly extracted coffee, typically over-extracted.

We reach another crucial point, extraction: the process by which hot water is passed through a filter of roasted and ground coffee. For a good quality espresso it is necessary that the coffee is neither overextracted (taking out an excessive amount of extracts due to too long extraction time, too fine grinding, water temperature or too high pressure that will give too much espresso bitter and astringent) nor under-extracted (in this case the extraction time is too short, the grinding is coarse, the temperature or pressure of the water are too low and therefore a little full-bodied and aromatic coffee will result).

In conclusion, "a good cup of espresso must be naturally sweet, have the right level of acidity and bitterness, a good body and rich and pleasant aromatic nuances". Forget also the myth of the 3C so dear to the Neapolitans. A fundamental parameter is the extraction temperature which also determines the tasting temperature. A good espresso is extracted around 92 ° / 93 ° and must be tasted in a lukewarm cup.

So how do you recognize a good espresso at the bar?

Coffee beans must have a "friar's tunic" color, a not too dark shade of brown, and not be "too shiny, sweaty". Coffee must be ground at the time of extraction, because oxygen is its worst enemy. Think that 15 minutes after grinding the coffee has already lost 50% of the aromas, after 24 hours the first aromas of rancid appear (which also give hints of mold in the coffee). The bartender must purge (or flush) after each dispensing, by running water through the machine. The coffee powder must be pressed with energy (imagine a pressure of 15/20 kg) from top to bottom with a press and the extraction must last from 25 to 30 seconds. Finally, very important are the cleaning of the machine and the coffee grinder, to be carried out at least once a day. The major defects, in fact, often derive from the extraction of residual coffee powder or traces of dirt inside the machine. Ask your trusted bartender what type of blend he is serving: the variety, whether Arabica or Robusta; the percentages of coffee in the blend, to know what kind of taste to expect; the origin. But remember: if you see a lot of coffee already ground in the container of the coffee grinder, don't expect a good espresso!

Text by Romina Ciferni