May 02, 2021

Tasting and Describing Coffee: Acidity

By Scott Thomas
Image of a coffee tasting sampling coffee in a tasting competition with samples in front of him

In a previous article we discussed tasting and describing your coffee, over the next few weeks we will dive a little deeper.

Acidity is desirable in coffee.  In a well-balanced cup, it could be described as the taste of biting into an apple … fruity, crisp, and refreshing.  There are more than 30 acids in a cup of coffee.  You need to have the correct balance of acids for a pleasant tang to your coffee.  Think of it has the right balance in homemade salad dressing.  You need the correct balance of oil and vinegar to achieve the pleasing flavor.

Let us cover several acids that have the most influence on the flavor. 

              Chlorogenic acids – chlorogenic acids make up most of the organic acids in coffee.  These acids are destroyed the longer the coffee roasts.  Therefore, beans with shorter roasts time are considered bright.  Although coffee is not that acidic for some people the chlorogenic acid in coffee can trigger acid reflux. 

              Citric acid – this acid makes up the second most organic acid in coffee.  This acid is not produced during roasting, but rather the coffee plant produces the acid itself.  As you may have guessed, the citric acid in coffee and citrus fruit is the same.  While citric acid may provide the flavor notes of orange, lemon, and even grapefruit in high concentrations, it will make the coffee sour.

              Malic acid – malic acid contributes flavors of peach, plum, and pear.  Since this acid is found in high concentrations in apples, you may also note a flavor of apple in your coffee.

              Quinic acid – as chlorogenic acids are destroyed during the roasting process quinic acid forms.  So, there is more quinic acid in darker roast coffee.  This acid contributes to your coffee’s mouthful trait (body) and continues to form as your coffee sits.  Therefore, coffee that sits for hours has a bitter taste.

              Phosphoric acid – phosphoric acid is an inorganic acid and tastes sweeter than other acids.  When citric and phosphoric acid combine it produces a flavor of grapefruit or mango. 

              Acetic acid – this is the main acid in vinegar.  While this acid can produce an unpleasant and fermented taste to coffee, in the proper balance you may taste a note of lime.

Acidity is a difficult tasting trait to perceive for many.  Try tasting a lemon and take note of how and where your mouth reacts.  Then taste your coffee and take note if your mouth reacts the same way.  Do you feel a tart tingle on your tongue or perhaps that mouthwatering sensation on your cheeks?

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