Acid in coffee | Coffee workshop

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For those who often drink individual coffee, when it comes to sour coffee, most of them will think of Yejia Xuefei, which is indeed the representative of acidic coffee. Beginner friends who have not come into contact with individual coffee may wonder why the coffee is sour. If the coffee is sour, is it a bad coffee that has expired? In fact, this acid is not the other acid, coffee contains hundreds of acidic compounds. Today, we will mainly introduce the acids in several kinds of coffee that affect the taste.

[citric acid]

Citric acid is an important organic acid. Citric acid in coffee is one of the products of coffee tree respiration. The amount of citric acid can be used to judge whether raw beans are fresh or not. As the maturity of coffee cherries increases, the content of citric acid will decrease and will be converted into more sugar. Citric acid reached its peak in shallow baking and was decomposed continuously in the later stage of baking.

[malic acid]

Malic acid exists in apples, Hawthorns, grapes and other fruits. The concentration of malic acid in raw beans is lower than citric acid. After baking, the concentration is reduced to only 0.1% of the raw bean weight. Malic acid is generally classified as aromatic acid.

[tartaric acid]

Tartaric acid exists in many plants, such as grape and sour horn. It is one of the main organic acids in wine and one of the sources of astringency in coffee.

[acetic acid]

Acetic acid, also known as acetic acid, glacial acetic acid, is an organic acid. Typical fatty acids are the source of sour and pungent odors in food. In coffee, it mainly comes from the fermentation step in the process of coffee post-treatment, so the content of acetic acid in washed coffee is generally higher than that in sun-cured coffee in the process of water-washing fermentation. The pressure in the roaster during the baking process can significantly increase the content of acetic acid, maintain the volatile acidity and improve the quality of coffee. A small amount of acetic acid makes the coffee fermented, but if excessive, it will make the coffee bitter in vinegar.

[chlorogenic acid]

Chlorogenic acid is a common acid in all raw coffee beans, accounting for 6% and 8% of the net weight of coffee. Coffee is the plant that contains the most chlorogenic acid in the world. Chlorogenic acid is an important source of coffee acidity and bitterness, and has a slight nerve stimulating effect on people. Chlorogenic acid is one of the main acidic substances in coffee. Chlorogenic acid has two isomers, monocaffeoic acid which is decomposed during baking and dicaffeoic acid that will not be decomposed. Among them, dicaffeoic acid can make coffee bitter and metallic. During baking, chlorogenic acid is broken down into quinic acid and caffeic acid, which increase the astringency and taste of coffee.

[phosphoric acid]

Phosphoric acid is found in Kenyan coffee with a high concentration of inorganic acid, which makes Kenyan coffee unique and excellent acidity. The phosphoric acid in coffee accounts for only about 1% of the total coffee substance, and mainly comes from phytic acid hydrolysis in the soil. In baking, the content of phosphoric acid increases with the deepening of baking degree. Phosphoric acid increases the brightness and sweetness of coffee.

There are a variety of acids in coffee, and these are the most important acids.

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