How many times can I repeat making hand-brewed coffee? How many times can I make hanging coffee? Can coffee be brewed as many times as tea leaves?

It can be said that no matter what method is used to extract coffee, the use of coffee powder is disposable. When we pick up a cup of coffee, the coffee grounds left in the filter will be discarded directly. So Qianjie believes that in many cases, friends will inevitably think: why can't coffee be brewed many times?

It is not surprising that such an idea came to the front street, because coffee, like tea, is a drink that needs to use water as a medium to dissolve substances. Since tea can be brewed many times, is it the same with coffee?

It is! If we want to, a cup of coffee powder can also be brewed as much as tea. Because the components of coffee beans are not only 70% of wood fiber, but also 30% of soluble matter. These soluble substances are the main source of coffee flavor, they stick to the cell wall of coffee beans, dissolved in water, will be taken out along with the release of hot water! If we use the brewing method of tea to brew coffee, then this coffee powder can still release the flavor even after brewing for many times or for a long time. Because the extraction efficiency is not high, so each time the substance in the coffee can only dissolve a few, not completely. And even if it is a normal extraction, we can also carry out secondary brewing for the same reason. Then a friend will ask, "in front of the street, since coffee powder can be brewed repeatedly, why do so few people do it?"

The answer is actually very simple, because the coffee made in this way: hold and drink! (not tasty)

Why is it not recommended to brew coffee multiple times? We call this behavior of dissolving coffee substances in water "extraction", while the percentage of coffee substances extracted by hot water is "extraction rate". Generally speaking, the extraction rate of each cup of coffee we extract is about 18%-22%. Because in this range, coffee will have a very good taste performance. If it is described as a cup of light-roasted coffee, Qianjie thinks it will be sour, sweet and tasty and full-bodied.

The reason why it should be limited to 22% is that 30% of the soluble matter of coffee is not all good. A cup of coffee is mainly made up of sour, sweet, bitter and salty flavors, which dissolve at different rates depending on the molecular size. The first to dissolve in large quantities is the sour substance, then the sweet substance, and finally the bitter substance. Because sour and sweet substances dissolve in large quantities at the initial stage of extraction, when the extraction rate reaches 22%, there are few sour and sweet substances left in coffee, and they are the essence of a cup of coffee. Therefore, if we extract 22% of the soluble matter of coffee and then continue to extract, then the coffee liquid released after that is likely to have only miscellaneous flavor and wood fiber.

If this part of the coffee liquid is added to the coffee with a suitable extraction rate, it will make the coffee full of miscellaneous and astringent taste, and it will dilute the original coffee concentration because the concentration of the liquid is too low. If it is taken out to drink, which is what we mentioned above as the second brewing, it is not necessary, because this part of the coffee liquid alone does not have any feeling, it is light, with a little miscellaneous smell.

Therefore, we can know that the reason why coffee is not recommended for multiple brewing is that we have already extracted all the "essence" of coffee in one extraction. The rest of the material can not support our reason for repeated brewing, after all, it is totally unnecessary.

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