Coffee knowledge: how do black coffee antioxidants come from? what's the effect?

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Coffee is the most complex food in the known natural substances. Scientists have isolated more than 300 chemicals from raw coffee beans and more than 800 kinds of cooked beans, including many acidic organic compounds, which are not only the source of the sour flavor of caffeine. It is also a healthy antioxidant.

Among them, the content of chlorogenic acid (chlorogenic acids) is the most abundant. Chlorogenic acid is not pleasing to the taste buds, but it has a strong ability of anti-oxidation and scavenging free radicals, which has been found to help the human body fight cancer. After baking, chlorogenic acid is decomposed into quinic acid (quinic acid) and caffeic acid, which also has antioxidant effect.

Coffee addicts agree that the most fragrant moment of ─ coffee is not when you drink it, but when you grind the beans and just cook them. The fragrance in the room makes people feel happy. This is the role of volatile antioxidants. The finer the ground beans and the more particles, the larger the total area of contact with the air, and the antioxidants will easily evaporate.

"only water-soluble antioxidants can be absorbed by the human body, and the finer the grinding, the higher the extraction rate, and the easier it is to dissolve organic acids and phenolic antioxidants," he suggests.

The relationship between grinding fineness and acid aroma extraction concentration. Take chlorogenic acid as an example, under rough grinding, coffee beans can extract 700mg chlorogenic acid per liter, if fine grinding can increase the dissolution to 1065 mg per liter, if ultra-fine grinding coffee beans, chlorogenic acid can be as high as 1177 mg / liter, 70% more than coarse particles.

Different coffee machines should use different grinding degrees.

Although theoretically, the finer the coffee beans are ground, the easier the antioxidants will dissolve, but in practice, it is still necessary to consider the way of brewing coffee and the length of brewing time to adjust a more suitable degree of grinding.

If the grinding is too fine, the water and the coffee powder surface contact too much, easy to extract too many impurities and bitter taste, but if the grinding is too rough, gouache contact is not enough, you will not be able to brew the aroma of coffee.

Therefore, generally speaking, the powder particles from fine to coarse, corresponding to the appropriate coffee machine can be divided into several types:

● espresso grinding (espresso grind): very fine particles, suitable for espresso machine.

● fine grinding (fine drind): suitable for mocha pot and hand dripping filter cup.

● grinding (medium grind): suitable for manual drip filter cup, American coffee pot, siphon pot.

● rough grinding (coarse grind): suitable for French filter kettle.

As for when to grind coffee to preserve the most complete nutrients? Chang Wen-Wei, director of the Taipei boutique Coffee Association and head of the Coffee consciousness Cafe, points out that if time permits, "grinding and cooking now" is the best, because once coffee beans are ground, the rate of oxidation and deterioration of coffee beans is accelerated, not only the antioxidants are decreasing, but also the flavor is getting worse.