The brewed coffee can retain its flavor for a long time by lowering the temperature immediately.

Experiment on how the flavor of brewed coffee changes when it is frozen and at high temperature to room temperature.

First prepare two cups, and 100ml's ice (ice in the rear measuring cup)

Pour the coffee liquid from the hand into two cups, each 80ml

Add 100ml ice on the left and the same amount of hot water on the right. (that is, the cup on the left will drop to several degrees in an instant, and the heat on the right will continue to be as high as 70-80 degrees.)

Then I waited until the two cups were returned to room temperature before tasting.

After the ice melted, I took a picture. it was interesting that the melted ice water did not fully blend with the coffee liquid. Maybe the quality of the coffee extract is larger than that of water.

After waiting for two and a half hours, both glasses went back to room temperature. The top of the cup on the left is a little darker than before, it has no taste, but it has fragrance.

Use chopsticks to make it even, "cup test"

Left: sweet and sour, fruity, honey right: just like the usual cold coffee, the sour, sweet and fragrance have weakened a lot, with a little miscellaneous flavor

It is obvious that the coffee will change its taste under the continuous high temperature. It turns out that before it changes, it will be cooled down immediately, and the flavor will be preserved relatively intact after two and a half hours.

Therefore, it is recommended that if the brewed coffee is not guaranteed to be finished in a short period of time, add ice immediately to make it taste good.