It's so cold, why don't you hot the latte a little?

In winter, I'm afraid there's no coffee more popular than a hot latte. If there is one, it's Australia White! Anyway, it is believed that the sales of milk coffee in each coffee shop have a straight growth, while the increment of hot milk coffee is accompanied by some small demand, such as: boss! The temperature is falling too fast, please make the milk hot!

We know that, whether it is a traditional latte or a novel Australian white, for most coffee shops, milk will have a recognized temperature range of-55 °C ~ 65 °C, which is a mild and suitable entrance temperature. For beginner rookies, their teachers often have higher requirements for them: the milk temperature is accurate to 65 ±3 °C. The reason why there is such a high requirement, mainly at this temperature, the sweetness of milk will be more obvious, it will make the overall taste of coffee more mellow, flower pattern lasting, and can be well integrated with coffee, delicate and dense! So generally speaking, the temperature of milk coffee will not exceed 68 °C.

But if you use more than 70 °C milk foam to make milk coffee, you will find that this milk bubble will not look very good. In drinking, in addition to burning the mouth, this latte does not feel much sweetness. And, can obviously feel that the milk foam and coffee show a separate state, and do not blend together, the taste is very rough, defoaming speed is also much faster! The overall experience is not very good, so generally Qianjie will tell guests that the milk temperature can be higher, but it will not be hot.

(the picture has nothing to do with 70 °C milk, but a friend on the front street doesn't look very good.) Why does the experience feel worse when the milk temperature is raised? The main reason is the deterioration of protein! Milk foam is mainly composed of protein in milk and injected air. When we pass away the milk, with the gradual increase in temperature, the two characteristics of the proteins in the milk that are originally entangled will be gradually released into a hydrophobic and hydrophilic form. The steam injected during the dismissal contains more water, so the hydrophobic end of the protein wraps the injected air to avoid the added water, forming bubbles, and the periphery of the bubbles is a barrier formed by the hydrophilic end. this is how milk bubbles are formed.

But these milk bubbles are not "invincible", it also has certain weaknesses. When the milk temperature exceeds 70 °C, the protein will be denatured or decomposed rapidly, which will directly cause the bubble formed by the protein to burst and deteriorate. Moreover, this layer of milk foam will also be fused after fusion. Due to the temperature difference between coffee and coffee, it directly produces "bubble, coffee" separation, resulting in a very rough taste!

(the milk foam sent to 71 °C defoams quickly) and in terms of sweetness, as Qianjie said, it is affected by the temperature! The sweetness of milk comes from the lactose it contains, but lactose is not as sweet as fructose. If we quantify the sweetness of sugar, the value that sucrose can give is 1.0, while lactose is only 0.16! Although it looks low, it is interesting that we can feel different lactose sweetness because of the different milk temperature.

Just like coffee, when a cup of coffee is sour, we can only feel a little sour taste at high temperature, but when the temperature drops, the perception of sour taste will be magnified, and this cup of coffee will have a more sour taste experience. The range of 60 °C ~ 70 °C is the most obvious time for lactose sweetness! Qianjie specially did an experiment to test the sweetness of milk at different temperatures, and it turned out to be true. Milk in this range can sense sweetness more easily than hot milk at other temperatures. But when the milk temperature crosses 70 °C, our perception of the sweetness of lactose in milk will be greatly reduced, so it will not be so sweet to drink!

Second, when the milk temperature is sent above 70 °C, these phenomena will become irreversible negative. In other words, even if you wait for the temperature to drop to the normal temperature, this cup of coffee will not taste as good as the coffee made directly at this temperature, because the protein in it has been damaged and cannot be repaired. Although the temperature has come down, it is still not good! So this is why beginners will have more accurate milk temperature requirements, so that they can know where the insurmountable peak of milk temperature is, so as to avoid making bad-looking and bad milk coffee because the temperature is too high!

If we are worried that the coffee will cool too fast, we can raise the temperature appropriately, but not too much. 68 °C is already the peak! In addition, we can also choose the ceramic cup as the milk cup, because the ceramic has a certain thermal insulation property, put it on the coffee machine before use, or preheat it with hot water in advance, all these can effectively slow down the cooling rate of milk.

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Front Street Cafe

No. 10 Baoqian street, Yandun road, Dongshankou, Yuexiu district, Guangzhou, Guangdong province