Whether 30 ℃ 60 ℃ or 90 ℃ should be used to make coffee foam is more suitable for different temperature performance.

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We often say that the best temperature for making milk coffee is about 50-70 ℃. Why is this? Today, the editor will discuss this issue with you.

The editor sent four cups of milk bubbles at different temperatures to observe the process of foam disappearing over time. The temperature of milk is 90 ℃, 60 ℃, 30 ℃ and 12 ℃ respectively.

The process of foaming milk:

(the picture above shows the time when the defoaming begins)

In the case of 90 ℃, the foam will expand rapidly even if the foam is not deliberately foamed when it is over 70 ℃, and the temperature will continue to tumble. When it is close to 90 ℃, Xiaobian's milk has already spilled out of the milk tank (pictured above), stopping at 94 ℃. There are obvious traces of defoaming in about 1 minute and 30 seconds.

60 ℃ of the situation is: this is our more commonly used temperature, according to the routine operation of milk foam, feel hot stop, the temperature is 63 ℃. Obvious defoaming marks appeared in about 10 minutes and 50 seconds.

The case of 30 ℃ is: foaming according to the conventional method, the feel temperature is warm, and the stop temperature is 33 ℃. Obvious defoaming marks appeared in about 4 minutes and 20 seconds.

In the case of 12 ℃, we use the milk directly from the refrigerator, using a manual hairdresser, the temperature of which is 8 ℃, and the temperature after discharging is 12 ℃. Obvious defoaming marks appeared in about 5 minutes and 15 seconds.

After observing the milk bubbles, the editor chose three temperatures of milk bubbles to put in the coffee for comparison.

The editor tested the boutique espresso beans from Qianjie (roasting degree: medium and deep roasting; coffee beans: 100% Arabica Columbia 4: Brazil 6).

Espresso: 40 grams, extraction time: 25 seconds.

In the case of 80 ℃, the foam is very thick, the foam on the wall of the cup disappears obviously, and the foam pattern is slightly diffused. The defoaming time is about 2 minutes and 30 seconds.

In the case of 60 ℃, the foam does not change after it has disappeared to a certain extent, and the foam is still very dense to see small bubble eyes. The pattern of the foam will spread a little bit outward, similar to 80 ℃. The defoaming time is about 6 minutes and 15 seconds.

In the case of 40 ℃, the foam does not change to a certain extent, and the foam is slightly thicker than that of 60 ℃, and the spread of the foam pattern is more obvious. The defoaming time is about 3 minutes and 45 seconds.

Through the above experiments, we can draw the conclusion that the state persistence of milk foam in the range of 50-70 ℃ is the best either in pure milk or after adding coffee, for two reasons: first, there is sufficient mixing time between milk foam and milk liquid; second, during the period when milk begins to denaturation but does not reach irreversible denaturation, the stability is higher.

There are two kinds of proteins in milk: whey protein and casein; whey protein begins to denature at more than 60 ℃. So when we send it to about 90 ℃, the protein is not elastic enough, so the foam will dissipate faster.

When the foam is sent to about 30-40 ℃, the foam dissipates relatively quickly due to the lack of mixing time between the foam and the milk liquid after foaming.

The reason for the rapid defoaming of frozen milk bubbles is that we use manual hair clips, and the degree of mixing cannot be compared with that of high-speed mixing of steam rods, and the degree of fusion is not high. in addition, the period of transition from low temperature to room temperature is a heating process for milk bubbles, oppressed by external heat, and the internal gas expands by heat, so the explosion of milk bubbles is more obvious.

Therefore, the ideal temperature for a cup of milk coffee is within the range of 50-70 ℃, and it is also suitable for the entrance temperature, which is neither hot nor too cold.

END