The flavor difference between hand-brewed coffee at high temperature, medium temperature and low temperature can coffee be heated again

Good coffee should be drunk while it is hot, so that you can better feel the rich flavor and taste of coffee. This is a mantra often spoken on the street.

Although Qianjie has not been able to completely get rid of short-sleeved sleeves until now, with the approaching pace of autumn and winter, in the cool indoor space, the freshly brewed hot coffee has turned cold in the blink of an eye after a while. Not only is the aroma at the entrance greatly reduced, but the taste is not as good as the one that has just been washed out. It can be said that it is tasteless to eat and a pity to abandon it. Therefore, the frugal friend immediately thought of reheating it.

What changes will coffee undergo when it changes from hot to cold?

Generally speaking, flavor substances will be washed out by hot water during the extraction process of coffee and exist in the form of "movement." The reason why we think coffee tastes good is because we smell the aroma of coffee that wafts into the air, and the other is that we feel the sweet, sour and bitter taste brought by coffee. So what are the main changes when coffee changes from hot to cold?

At different temperatures, the human body's senses are sensitive to sweet, sour and bitter, with bitterness always ranking first. When tasting coffee at medium and high temperatures, the hot feeling of liquid contacting the mouth will override the perception of taste buds, thus reducing the sensitivity to bitter taste. However, once the liquid contacted is completely cooled, the effect will be the opposite, and the bitter taste will rise in a straight line, and the coffee liquid will become difficult to eat.

Sweet taste is another situation. When the temperature of coffee is close to the temperature of the human body, we will more easily perceive the sweetness. When the temperature drops, the sensitivity of taste buds to the sweetness gradually decreases, so the sourness and bitterness are more prominent. In addition, after the coffee cools, part of the oil will gradually oxidize as it cools, resulting in the taste no longer smooth, and another part of the soluble matter will also begin to condense, giving the coffee a sour taste.

In addition to the perceived changes in its own temperature, coffee is not good after getting cold because the aroma substances in it have been greatly lost. Qianjie once mentioned in a past article that coffee flavor is a volatile substance. Whether it is coffee beans ground into powder or a cup of coffee brewed in hot water, the aroma will follow the moment it comes into contact with the air. Accelerate loss.

Take Qianjie just made a cup of Sidamo Alo in the morning for example. In the range of 50 - 70°C, you can first smell the aroma of white jade orchids and sweet oranges, and the sweet and sour texture of pineapple and mango at the entrance; when the temperature drops to close to the human body. In the range of 35 - 50°C, the bright acidity of citrus is more prominent, accompanied by the charm of black tea; However, once the temperature drops below 30°C, not only will the above-mentioned aroma be lost when drinking, the coffee liquor becomes obviously turbid, there is obvious sour and bitter taste at the entrance, and the mellow degree is lacking, making people unable to help but shiver after swallowing.

What does it mean to reheat coffee?

In theory, when cold coffee is reheated, the taste buds 'perception of sweetness will be "activated", and then the bitterness will be covered again. At the same time, the stimulation caused by the sour and astringent taste will be suppressed to a certain extent, making the coffee change. Return to a better tasting state.

Therefore, if the coffee is cold, we can indeed try to "save" it by warming it up. Although the taste is not as rich as before, it allows us to finish the remaining coffee without wasting it. Why not?

But as described above on the front street, as the temperature of the coffee drops, the volatile flavor substances have been greatly exhausted. At this time, secondary heating will no longer help the lost aroma, and only a faint "coffee flavor" remains. Moreover, during the reheating process, the unpleasant taste components that appear after the coffee cools will also participate in the heating up and gather together, thus exacerbating the negative taste of the coffee.

What should I pay attention to for secondary heating?

In order to get rid of this unfriendly taste, Qianjie recommends that it is best to avoid exceeding the body temperature too much when reheating coffee, that is, not to make the coffee too hot. In addition, since different coffee beans have different performance characteristics, we can adjust the warming range according to their flavor tonality.

The flavor of medium and light roasted coffee is mainly fruit acid and light texture. When we heat it, we can raise its temperature to 50 - 70°C, so that the acid can easily turn back to brightness; for medium and deep roasted coffee that pursues a mellow body, it is advisable to control the temperature in the range of 35 - 50°C close to the human body temperature during secondary heating, because at this time, the tongue feels the sweetness most clearly, and the coffee will be easier to drink.

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