The acidity of the coffee: value or defect?


We often hear about acidity in coffee and just as often it is associated with a negative sensation.

With this article, I would like to be able to explain what the acidity of coffee is, where it comes from and what it depends on, in order to be able to taste each future coffee you drink in a more in-depth and more enjoyable way.

Let's start with the definition: acidity is one of the five flavors, along with sweet, salty, bitter and umami. It is perceived by our body thanks to the taste buds of the tongue.

Then looking at the pH level scale that goes from 0 to 14, in which 7 is the neutral value, the coffee takes on a value of 5, therefore acid. Like coffee, all foods have a particular and specific chemical composition and a certain degree of acidity.


In our case, the coffee beans have dozens of acids, the main one being chlorogenic acid.

Most of these acids are reduced with increasing temperature.

These acids are essential in our cup!

In fact, in addition to making our coffee more complex, as we will soon discover, they also have important antioxidant and anti-inflammatory properties, with positive effects on our body.

After introducing the term and explaining it from a chemical point of view: what does the acidity found in coffee depend on?

The acidity depends on several factors:

  • the species
  • the altitude
  • terroir
  • by the processing method
  • the degree of roasting
  • the extraction

In general it can be said that the Arabica species is more acidic than the Robusta species.

This argument can also be applied to blends.

So if you buy a blend with a higher percentage of Arabica, you will get a fresh and pleasant acidity in the cup, exactly as it happens in our Allegro blend FIND OUT MORE >>

while if you buy a blend with a higher percentage of Robusta, your cup will tend to have a more bitter flavor, for example like our Stretto blend FIND OUT MORE >>

o Vivace FIND OUT MORE >>

This also depends on the altitude at which the coffee was grown. Also in this case, in general, the coffees grown at high altitudes are more acidic than those harvested at low altitudes. This is because the higher you go, the more rocky and / or rich in mineral salts, some of which have an acid taste.

In this way, the preceding statement is also explained, given that Arabica quality coffees are grown from 900 m above sea level, up to 2000-2200 m; while the Robusta quality coffees are found in the plains, up to about 900m.

So we can say that acidity depends on the terroir in which our coffee plant grows, exactly as it also happens with grapes for wine.

To give a concrete example, an Ethiopian or Kenyan coffee will certainly be more acidic than a Brazilian or Vietnamese coffee.

In addition, acidity also depends on the processing method that takes place on the plantation. In fact, once the drupes are harvested from the plants there are two main processes: natural or washed.

With the first, dry, the beans extracted from the drupes are left to dry in the sun, which gives greater sweetness in the cup.

In the second, the washed one, instead, the drupes are left to ferment in water and then go to de-pulp and dry the grains only afterwards in the sun. This gives more acidity in the final result.


But not only!

As we had already anticipated, the acidity also depends on the level of roasting that the roaster applies to the beans.

The concentration of acids in coffee beans decreases with increasing temperatures. The more lightly roasted the coffee, the more acidic it will be once extracted in the cup, and on the contrary, the more it will be roasted and the less acid it will be, preferring hints of bitterness and even burnt, if the roasting is really strong.


Finally, if we consider an espresso, the acidity also depends on the correctness of the extraction.

Let me explain: an under-extracted coffee will be more acidic than one extracted in the correct ways and times, and also than an over-extracted one. This is because when the coffee is under-extracted it means that the water has "passed" too quickly through our ground coffee and therefore has not been able to extract all the substances contained in the coffee, such as fats, sugars and so on. Almost only the acids have been extraced, the first to go down into our cup.


Now the time has come for the question you are surely asking yourself: is acidity in coffee a value or a defect?

The acidity in the coffee is a virtue!

It is one of the most representative parameters for understanding the difference between a complex coffee and a flat and characterless one.

A right level of acidity, and I stress right, in fact manages to give the drink that typical freshness of citrus fruits.

At the same time, however, like everything: too much is good: it must never be excessive or too pungent, in that case it would be considered a defect, as much as an excessively bitter coffee, with an empyheumatic aftertaste, i.e. ash and burnt.

In addition, the acidity can also be balanced by sweeter notes, such as those of ripe pulp fruit, or the typical sweetness of berries. Or from more roasted notes of chocolate, roast, caramel, etc.

The art of balancing lies in the hands of the roaster, who tests and carries out tests for each specific single origin, to arrive at the perfect roasting curve for those specific beans, to be able to bring out all the positive aromatic notes to the maximum.

However, this is only feasible with a medium roast, as a light one enhances the acid notes more, while a dark roast makes the coffee only bitter, hiding all the other aromas.

This is why we at Caffè Ernani have opted for medium roasting.

However, acidity is often considered a negative sensation, partly out of habit, because too often simply bitter coffees are served, and partly because it is confused with astringency or sourness.

This is because we have memorized that when we eat a lemon, a typical acidic food, we also feel astringency, that is, that sensation of a lapped palate, we feel a sensation of sand and saliva is reduced, drying the mouth.

However, this sensation in coffee is considered a defect.

So a coffee can be acidic, but never should be astringent!

I conclude by saying that everything I have said so far is valid on an objective level. After which subjectivity comes into play: each of us can enjoy different coffees, coffees with more acidity or more balanced coffees. For example, I prefer very acidic coffees, with very intense aromatic notes of citrus.


What type of coffee do you prefer? Write me an email at and tell me your opinion!

Martina Mazzoleni 

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