Coffee cold knowledge the finer the coffee beans are ground, the better the antioxidant effect

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Coffee is the most complex food known to be composed of natural substances. Scientists have isolated more than 300 chemical substances from green coffee beans and more than 800 kinds from cooked beans, including many acidic organic compounds, which are not only the source of coffee sour flavor, but also beneficial antioxidants for health.

Coffee is the most complex food known to be composed of natural substances. Scientists have isolated more than 300 chemical substances from green coffee beans and more than 800 kinds from cooked beans, including many acidic organic compounds, which are not only the source of coffee sour flavor, but also beneficial antioxidants for health.

Among them, chlorogenic acids are the most abundant. Han Huaizong pointed out that chlorogenic acid is not pleasing to taste buds, bitter mouth, but it has strong antioxidant and free radical scavenging ability. Research has found that it can help the body fight cancer. After roasting, chlorogenic acid is decomposed into quinic acid and caffeic acid, which also have antioxidant effects.

Coffee drinkers agree that the most fragrant moment of coffee is not when drinking, but when grinding beans and just cooking, full of fragrance teaches people to feel happy, this is the role of volatile antioxidants, the finer the ground beans, the more particles, the greater the total area in contact with the air, and the antioxidants are easy to volatilize and disappear.

So, to reduce volatility, grinding coffee beans to coarse particles improves antioxidant intake? Han Huaizong, author of Coffee Science, disagrees. He believes that if these volatile antioxidants cannot be dissolved in water, no matter how much they are left behind, they cannot be consumed.

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

The International Coffee Organization has conducted a series of experiments to calculate the relationship between grinding fineness and acid aroma extraction concentration. Take chlorogenic acid as an example. Under coarse grinding, 700 mg of chlorogenic acid can be extracted per liter of coffee beans. If the coffee beans are finely ground, the dissolution amount can be increased to 1065 mg per liter. If the coffee beans are finely ground, 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 are to dissolve, in practice, it is still necessary to consider the way coffee is brewed and the length of brewing time to adjust the more suitable grinding degree.

If ground too fine, water and coffee powder surface contact too much, easy to extract too many impurities and bitterness, but if ground too coarse, water powder contact is not enough, can not bubble coffee aroma.

Therefore, in general, the powder is fine to coarse, and the corresponding suitable coffee machine can be divided into several types:

● Espresso grind: Very fine particles, suitable for espresso machines.

● Fine drind: Mocha pot, hand rinse drip filter cup.

● Medium grind: suitable for hand drip filter cup, American coffee pot, siphon pot.

● coarse grind: suitable for French press pot.

As for when to grind coffee to preserve the most complete nutrients? Chang Wen-wei, director of the Taipei Fine Coffee Association and head of Coffee Awareness Cafe, points out that if time permits,"freshly ground and brewed" is best, because once coffee beans are ground, oxidation and deterioration speed up, not only the antioxidants decrease, but the flavor also deteriorates.