Why does coffee need so much ice? What is the specialty of hand-made ice cubes in coffee shops?

Many customers have had this question. Why is it difficult for the ice cubes they made at home to achieve a good cooling effect? They melted all after throwing them into the water for a while, but the ice provided by the coffee shop melted so slowly that they seemed to be "unscathed" until we finished the entire cup of American style. Why? What kind of "special ice" does coffee shops use?

The role of ice

Qianjie wrote an article,"What are the key points about coffee with ice?" As mentioned in the book, as an indispensable auxiliary role in cold drinks, ice cubes not only play a recognized role in cooling down, but also serve us to simultaneously achieve the purposes of locking in the aroma of coffee, adjusting the concentration and maintaining low temperature, thereby making Iced coffee taste better.

In addition, the different making processes, shapes and volumes of ice cubes will affect the tasting effect of a cup of cold coffee from the completion of production to the first sip, and to the final consumption.

What ice does coffee shops usually use? Why not make it easy?

Based on various factors, when cafe owners choose an ice solution, the first priority is to solve the problem of production efficiency, so they will first consider using an ice machine; secondly, they will make the frozen coffee have an ideal taste, so use ice cubes that "cool quickly and melt slowly", and formulate corresponding "ice adding strategies" for different drinks based on actual conditions.

Ice freezing and ice melting are actually processes of heat conduction. There are many factors that affect the heat conduction rate, such as the temperature of the surrounding environment, the temperature of the liquid and the ice itself, the contact area between the ice and the liquid, etc. As far as the phenomenon that "ice cubes in coffee shops melt slowly" is concerned, Qian Jie believes that differences in equipment and the amount of ice cubes are the main reasons.

Compared with the refrigerators we have in our homes, the commercial ice maker specially designed for operating stores has only one "ice freezing" function. The core of this is the high efficiency and continuous and stable output of ice cubes. The ice cubes produced by it are both in terms of purity and hardness., and core temperature are stronger than the former. Moreover, in order to achieve multiple uses, the ice cubes produced by such equipment are usually regular square or crescent shapes, which are small in size and are more conducive to stacking in structure;

Most of the ice cubes made in our home are small round balls or irregular squares. Not only will the bulk density be low in the cup, but the volume proportion will be larger under the same weight. Therefore, ice from coffee shops melts more "slowly" than ice from household refrigerators. In addition to the difference in its production processes, the actual ice cubes produced by coffee shops account for a larger proportion of ice cubes.

Can the refrigerator make "special ice"?

If considering the above listed situations, it is obviously the most preferred to use an ice machine to open a store. Why does Qianjie still insist on using a refrigerator to freeze ice cubes?

Although commercial ice machines can indeed solve the problems of many of our products to some extent, since such ice cubes are generally too small in size and are mostly hollow, when placed in coffee hotter than it, it will be easy to melt. The speed is too fast, resulting in the situation where the coffee is over-diluted early before the temperature drops. In a high temperature climate of 40 ° C, iced coffee will not last long.

After comprehensive consideration, in order to allow all iced coffees on the menu to achieve better cooling and diluting effects, and to solve the problem of quickly returning to temperature and taste after cooling, Qianjie decided to adopt a static freezing method, that is, choose a large mold to make ice directly in the refrigerator. This kind of operation has both advantages and disadvantages. The advantage is that it can obtain solid ice with a large enough volume to adapt to all kinds of coffees, which is popular among everyone; the disadvantage is also obvious, that is, low efficiency, and water must be filled manually every time. It takes at least 40 hours to successfully freeze a set of ice cubes.

In addition, in order to explore whether the freezing time of ice cubes is related to its melting speed, Qianjie also conducted a small experiment. The ice cubes just taken out of the freezing mold and the "old ice cubes" peeled off two days ago were used in the same set of parameters. Cook the same bean to see if there is a gap. The specific parameters are as follows:

Coffee beans: Qianjie Huakui coffee beans

Powder amount: 15g

Powder to water ratio: 1:10

Ice cubes: 80g (4 pieces)

Water temperature: 92~93℃

Abrasion degree: EK43s-9 grids/C40-22 grids

Three-stage: 30g +60g +60g

(Refrozen ice cubes on the left, directly demoulding ice cubes on the right)

Although the two pots of Huakui Ice Hand Chop show soft tonality of tropical fruits, oranges, cream and black tea, there is some gap in taste and intensity. Compared with the newly demolded "new ice" coffee, the re-frozen and cooled Huakui not only has a fuller citrus acid and black tea feeling, but also maintains a longer low-temperature experience in the cup. After fully warming, you can also drink a hint of honey-like sweet finish.

This is because under the same volume, the refrozen ice cubes are exposed to cold for a long time and are much stronger than fresh ice cubes directly demolded. Therefore, even in hot coffee, it melts slower, allowing the coffee If the liquid is diluted and cooled in a short period of time, the corresponding flavor and intensity will naturally be higher.

If you also want to make the ice more strong and easy to use, you might as well choose a slightly larger model to make ice manually like Qianjie did. When the water is completely frozen into a solid state, remove it from the mold, and then store it in a clean container. Keep it and take it as you please.

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