How long is it best to finish making coffee by hand? How long can a brewed coffee thermos bottle last? Why does coffee not taste so good after it cools down?

Recently, when I was surfing the Internet in Qianjie, I found a very new term called "prefabricated" hand flush! What is "prefabricated" hand punching? As soon as I read the post at the current street point, I found that the merchant brewed the coffee in advance and then put it into the insulation cup. When the guest orders, pour out the product from the thermos cup. As a result, many friends asked: can this kind of "prefabricated" hand flush taste good?

It is reasonable that there will be such a problem. I believe everyone in Qianjie has felt the process of hot coffee gradually "turning sour". Coffee from just brewed when the aroma, taste soft, with the temperature drop gradually into a cup of mediocre aroma, exciting taste of coffee. Changes in aroma and taste all imply that the "good taste" of hot coffee has a very short "shelf life". This change is mainly caused by two reasons: the change of temperature and the volatility of aroma. It is well known that most of the flavor substances of coffee are volatile, so they begin to volatilize from the end of roasting. Especially after grinding into powder and brewing into coffee, the loss rate of these flavor substances will be greatly accelerated. So this explains why the aroma of coffee from the beginning to the nostrils, with the passage of time gradually become mediocre, because most of the volatilization.

Then there is the temperature, because our taste buds' perception of the five flavors varies with the temperature, so when the coffee cools down, the taste we drink will be different from that when it is hot. Coupled with the disappearance of the aroma, the coffee will not taste so good after it has been kept for a long time. But on second thought, the function of the thermos just limits the impact of these two situations on coffee. The heat preservation function makes the temperature of the coffee drop slowly, and the sealing function makes the aroma substances volatilize less. So in theory, putting coffee in a thermos can prolong the "tasty period". Instead of talking about soldiers, it is better to prove it directly with experiments! Then we will conduct an experiment on Qianjie to see how long the taste of hand-made coffee can last after it is put into a thermos flask.

Thermos flask, can you keep the coffee delicious? In fact, Qianjie has done similar experiments before, but the thermal insulation effect of the thermos used at that time is not so good, so this time Qianjie specially purchased a thermos bottle that can be kept for 12 hours for the experiment. In order to ensure the rigor of the experiment, before the start of the experiment, Qianjie will preheat all the utensils that the coffee needs to touch to ensure that the coffee does not lose too much temperature.

At the same time, the use of a fruit juice will be more full, sweet and sour coffee beans. Because the taste of this kind of beans is more prominent, it can make us more acutely aware of the changes in taste. Therefore, the coffee beans used in this experiment are: Asaria, Kenya. The extraction parameters are as follows: the amount of powder is 20g, the ratio of powder to water is 1:15, the grinding degree is 10 degrees of ek43, the over-screening rate of No. 20 sieve is 80%, the fine sugar is ground, the water temperature is 92 °C, the filter cup is V60, and the cooking method is three-stage.

Then we'll just skip the process! After brewing and cooking, I took a sip in the front street. This cup of Kenyan flavor is characterized by small tomatoes, black plums, yellow sugar and Sydney. It tastes sweet and sour and tastes clean. Then we put it in a thermos flask to seal and keep warm, and then try its taste every other hour!

The temperature measured on the front street was 71 °C when poured in, and the coffee temperature dropped to 66 °C after an hour of placement. But at this time, you can still smell a very obvious aroma, and the taste is the same as it was an hour ago, the same as the sour aroma of little tomato and black plum, the sweetness of snow pear, the taste is still clean, and the soup color is bright. By the second hour, the temperature dropped to 59 °C (how is it worse than the previous one), but the aroma and taste remained the same, not much changed, just because the temperature dropped, the entrance was better.

In the third hour, the temperature of the coffee dropped to 55 °C. Compared with the previous two cups, its aroma is less obvious, but the sweetness is higher. By the fourth hour, the aroma of the coffee has almost dissipated, and you can taste the taste of small tomato and black plum. The temperature is 51 °C, warm, drink can obviously feel the sour taste began to highlight, at the same time the soup color began to muddy.

Five hours later, it is difficult to smell the aroma close to the liquid surface of the coffee, only from the coffee to drink a relatively turbid taste, as well as sweet and sour taste. So at this point, the experiment is over. Well, from the above experiment, we can see that thermos can indeed delay the "taste period" of coffee. The performance of coffee will not change much in the first three hours. Therefore, it is understandable that merchants will adopt the behavior of prefabricated hand-made coffee in order to reduce the waiting time of customers (but whether consumers accept it or not). It can also be learned that if we want to drink a pot of hand-brewed coffee when we go out, in addition to carrying a full backpack of brewing utensils, it is also a good choice to use thermos to keep the coffee in advance. However, it should be noted that coffee is not pure water, and it is easy to breed bacteria after it has been kept for a long time, especially after 4-5 hours, when the temperature drops down, this is a proper hotbed for bacteria. So when we choose to flush by hand in an insulated bottle, try to limit the drinking time to avoid the impact on our health.

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