From beans to cups, what is the problem that makes coffee feel astringent?

We often drink the astringent taste in the coffee, but the astringent taste is often unacceptable, and it should not have the taste in the coffee. So the question is, where does the astringent feeling come from? There are four kinds of astringency: green, dry, raw and dry. Different astringency occurs for different reasons.

Green and astringent

Hard-picked melons are not sweet, but strong-picked fruits will be green and astringent. No matter what kind of fruit in the world, if it is not harvested by force, it will make the fruit sour and sharp, the sweetness is not good, the aroma is insufficient, and the most troublesome thing is that the astringency of the fruit is obvious. The astringency that is not yet mature is green.

Green coffee beans are more common in commercial beans, because commercial beans are usually planted at low and middle elevations, and the amount of production is relatively large, so they are mostly harvested by machines, and the machines will not distinguish between green and ripe. Once the machine goes through, it is harvested indiscriminately, and commercial beans are not screening beans, so commercial beans often drink immature taste. For coffee beans at high altitude, there is no way to harvest them by machine, but mostly by hand, so this will not happen.

Raw and astringent

In the case of coffee, the unripe fruit is called green and astringent, while the roasted unripe, or the water temperature not enough when the coffee is extracted, is called astringent. Coffee made from green and astringent fruit shows astringency when it is hot. When coffee is hot, it may also modify the sour taste. Once the temperature drops to medium or low temperature, the astringency will be revealed. The colder the coffee is, the more sour and astringent it is, which is why we advocate not drinking cold coffee.

Dry and astringent

Dryness occurs when coffee beans are roasted. After the coffee is roasted, there is enough water in the beans to lubricate and preserve the coffee: if too much water is left, the coffee is not cooked; but if there is not enough moisture in the beans, the beans will be too dry and the coffee will be dry.

Dry beans in the extraction process, the coffee powder will expand very much, this sense of expansion will make you think that the coffee beans are fresh, because only the fresher the coffee beans will feel better. Beans that have been kept for a long time will absorb more water because of the higher density of contact with the air. after the beans are wet, the coffee powder will be heavier when the water content of the coffee increases. And dry coffee, even if placed for a long time and then used to extract, coffee powder will expand. If there is a serious lack of moisture, the coffee powder will produce voids like the surface of the moon during extraction.

Dry and astringent

Dryness can occur when coffee is overextracted. What is over-extraction? Excessive extraction means that coffee is brewed for too long. How long is too long? Take Syphon (plug wind) for 2 people as an example, the coffee will be boiled for more than 25 seconds (from the moment the coffee pot is put into the pot, the time to turn off the fire), there will be astringency (because the glue is destroyed), and a longer time will cause dryness. Dry coffee in the mouth will get stuck in the throat, and the throat will feel dry and sore.