Why is coffee sour? How does the acid in coffee come from? the taste of coffee

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How to determine whether the acidity of coffee is good or bad?

The acidity of washed beans is higher than that of sun-dried beans. For example, the concentration of sun-dried beans is heavier than that of washed beans, because the concentration obscures the acidity of coffee. The acid substance of coffee beverage is closely related to the degree of baking, as well as the method of baking and brewing. PH of coffee is also related to the acidity of coffee. The pH value of a good cup of coffee should be between 4.9 and 5.2.

Coffee raw beans and roasted beans contain more than 100 acids. Chlorogenic acid and quinic acid are the main acid substances in raw beans, followed by malic acid and limonic acid. Chlorogenic acid complexes are degraded into smaller components during baking, forming components such as acetic acid and formic acid. Because of the high volatility of these ingredients, they disappeared in the subsequent baking stage.

Chlorogenic acid

Chlorogenic acid is actually an ester component between quinic acid and phenols like cinnamic acid. The most common coffee is coffee quinic acid (5-O-caffeoylquinic acid), an ester between quinic acid and caffeic acid. More than 17 different chlorogenic acids have been found in Robusta raw beans, but the amount of chlorogenic acid seems to vary depending on origin and coffee variety.

Caffeic acid

Coffee provides the richest dietary source of chlorogenic acid. According to the report, a cup of 200cc coffee contains 70-350 mg chlorogenic acid and will supply 35-175 mg caffeic acid. The chlorogenic acid in coffee has the effect of maintaining health. Although chlorogenic acid and caffeic acid have antioxidant effects in test tubes, the exact amount of antioxidant activity is unknown because they are widely metabolized in the body, and their metabolites often have lower antioxidant activity than predecessor substances.

Caffeic acid exists not only in coffee, but also in a large number of edible and inedible plants. With antioxidants. On the other hand, current research suggests that caffeic acid may also be a carcinogen. The health benefits of caffeic acid are unknown.