Why must ice cups be used in the production of Dirty? What does dirty mean? How?

Even today in 2024, the popularity of Dirty remains the same, and the production method of Dirty is in full swing on various platforms. When you think about it, the main points of its production are nothing more than three elements: the temperature of the cup, the concentration of milk, and the obvious degree of layering! The latter two Qianjie have been shared many times, but with regard to the Dirty cup, Qianjie only shallowly passes it every time, without mentioning its main function. So the question is: why are the cups used to make Dirty refrigerated by default? Neither room temperature nor freezing; what exactly is the effect of an ice cup?

Coffee experiment in order to understand its role, let's conduct a group of experiments to see the difference between Dirty made from room temperature, refrigerated and frozen cups. The production parameters of Dirty are as follows: refrigerated milk 180ml, espresso 40ml (20g powder, concentrated with 40ml extracted in 30 seconds). The production method is as follows: first pour iced milk into the cup, then extract espresso, put the cup containing milk under the outlet of the handle powder bowl to catch the concentration, so that the concentration can float on the surface! When the extraction reaches the target liquid weight, the extraction will stop, the cup will be removed, and the Dirty will be finished!

(if the bottomless handle is used, if the cup and outlet are too far away, we can put a spoon to slow down the impact of concentration, and the delamination effect will be better.) the room temperature glass: because the temperature of the glass is higher than that of refrigerated milk, when 6 °C ice milk is poured into the cup, it will be heated to 8 °C. Using it to make the Dirty, the layering effect is quite obvious at the beginning! During the first taste, there is an obvious temperature difference between milk and coffee. But from the second mouthful (about the second minute after making), the temperature of milk and coffee has been relatively close, and the temperature difference experience has gradually declined. In the third minute of production, the experience of temperature difference is almost gone! Because at this time, the temperature of milk and concentrate has been agreed.

Refrigerated glass: because it is in the same refrigerated environment, the temperature of the cup is close to that of milk. Therefore, when 6 °C iced milk is poured into the cup, the milk temperature will drop slightly to about 3 °C (as a result of the cup being lower than the milk temperature), and the effect of layering is very obvious!

In the first taste, we can clearly feel the hot and cold difference between milk and coffee. To the second bite, coffee and milk although a little blend, but still maintain a more obvious hot and cold temperature difference, the level is still the same. Although its temperature difference lasts for a long time, if you finish it in three minutes, you can maintain a more comfortable drinking experience.

Frozen glass: the frozen cup is so different from room temperature that it begins to come out of the water dozens of seconds after taking out the refrigerator. When the cold milk is poured into the cup, the temperature drops to about 1 °C.

The Dirty made from it is also layered, regardless of appearance or taste, can make us feel the difference between coffee and milk. And its delamination time is the same as that of a refrigerated cup, and there is not much difference. Through the above experiments, we can know that the reason why Dirty needs to be made with ice cups is that the cups at low temperature can better maintain the temperature of iced milk, so as to achieve a better stratification effect! Layering effect refers to both appearance and taste. The choice between refrigerated and frozen cups is due to the large gap between frozen cups and room temperature, resulting in a larger effluent. Considering all aspects of production and convenience, it is more appropriate to choose a refrigerated cup (refrigerated will also produce water, but not much)!

Interestingly, Dirty did not use ice cups at the beginning of its invention. Qianjie has shared it many times, and its inventor, Mr. Seiyuki Tanaka, only used ice milk and special concentrate to match it. Even if there is no special ice cup, the espresso he makes can maintain the stratification effect with iced milk for a long time because of its extremely high concentration. Until Dirty spread to China, the use of concentrate has changed. In order to pursue a more perfect taste, this has been added to the application of ice cup!

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