Why some coffee is sour (part 1)

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Acidity is the most controversial attribute in boutique coffee, although many boutique coffee lovers and competition judges like good acidity, but acidity often makes people confused.

What is sour? Why did you get the coffee? Is acid good or bad? More importantly, how to adjust the acid quality by cooking or baking?

Source: The Japan Coffee Man?

What is sour?

Lively, full-bodied, sharp, bright, fruity. These words are often used to describe acidity, although they have exhausted adjectives to describe them, but sometimes they still feel inadequate. After all, it is not easy to describe acid quality.

Mainly because the acid has many features, it affects the flavor and aroma, forming stone fruits, sweet peaches and apples and other taste feelings. At the same time, the acid quality will also affect the taste, as long as the professional cup tester can tell whether the acid leaves a stimulating feeling in the mouth, if there is no irritation, it means that the acid strength is very low or there is no acid.

Acidity is also a chemical compound, which affects whether coffee is good or not. Understanding the chemical composition of coffee can help bean bakers or brewers get better flavor.

Someone once said: "the acidity can give full play to the flavor of a cup of coffee, and it can also make the flavor unbalanced. When the sour taste is too heavy to cause irritation, it will make the drinkers disgusted and rejected." "

But if there is no acid, it will make this cup of coffee taste too dull.

Training coffee senses by identifying organic acids and fruit acids, source: Kata S á ra

Acidity under a microscope

Veronica, a doctor and coffee quality appraiser (Q grader), has studied the relationship between chemicals and coffee quality and flavor. He shows that coffee acids can be divided into organic acids and chlorogenic acids.

Organic acids include citric acid, malic acid, quinic acid, acetic acid, succinic acid and tartaric acid. These are the acids that bring fruit acid and good flavor. Veronica indicates that the organic acid in coffee is an indispensable factor in the presentation of flavor.

Each of these acids gives coffee different flavor characteristics:

Citric acid: this is the same type of acid as green apples. Try to associate coffee with juicy and sweet and sour green apples.

Malic acid: as you might think, malic acid is more citrus acid, try to connect with lemon, orange and orange acid.

Tartaric acid: similar to grape acid, it is also found in large amounts in bananas.

Acetic acid: in other words, an acid that is as irritating and unpleasant as vinegar.

Chlorogenic acid: it is usually broken down into quinic acid and caffeic acid during baking. The point is that quinic acid does not taste pleasant. Veronica added: these ingredients will form a bitter, astringent and sour taste.

For this reason, coffee with a lower degree of roasting usually tastes more bitter, while coffee with a lower degree of roasting tastes more acidity, which will be explained later.