If you can’t get Bing Dwen Dwen, then get its “rock sugar shell”!

Who is the latest “new top star”?

Bing Dwen Dwen must be on the list!

With its cute and futuristic appearance

He gained countless fans in a short time!

Does the crystal clear shell make you

Reminds you of a string of candied haws?

Image source: Tuchong Creative

The picture is from the copyright library, and the picture content is not authorized to be reproduced

Liu Pingyun, chief executive of the design of the Beijing Winter Olympics mascot Bing Dwen Dwen, said that as a southerner, his deep impression of the north is candied haws. The sugar coating of candied haws is liquid and solidified, and it has one thing in common with ice: it is transparent, which reminds people of ice and snow sports.

Unexpectedly, there is such a story in the design process of the mascot. But Pangke has a new question: how does solid sugar become the "shell" of Bing Dwen Dwen? Don't worry, let's take a look!

Look at my 72 transformations——

Various forms of sugar under different conditions

In order to satisfy the taste buds, various Internet experts have shown their special skills, and there are countless DIY tutorials. After watching several tutorials, Pang Ke summed up a rule: whether it is DIY caramel cake, DIY candied haws, or DIY hawthorn snowballs, the core is to boil sugar. Watching the sugar in the pot gradually become a slurry, bubbling, and gradually changing color... What kind of changes have occurred in this process?

How to make sugar

In fact, the reaction in the sugar boiling process has a special name in chemistry, "caramelization reaction", which refers to "the dehydration and cracking of sugars when heated or treated with dilute acid at high concentration. The volatile aldehydes and ketones produced by the cracking condense and polymerize to form a brown substance."

Sucrose molecular structure

Take sucrose as an example. In the above process, sucrose is first heated to melt, and then heated to produce bubbles. The primary product is isosucrose, then isosucrose, sucrose glycoside, and sucroseene. Continuing to heat will further polymerize and condense to produce a high molecular dark insoluble substance called caramel, which is a colloidal substance, and thus produces the "thick, colloidal" brown substance we see at the end. Caramel color, a product of caramelization reaction, is also often used in foods such as braised pork, cola, soy sauce, and beer on the table to improve their appearance.

In addition, it can be said that every step of "boiling sugar" is the essence. Let us review the whole process of sugar changes.

Sucrose and water (or oil) are added to the pot in appropriate proportions to make sugar solution. Although the physical and chemical properties of sucrose are relatively stable during the heating process, it also has certain special properties. The viscosity of the saturated solution of sucrose will decrease at low temperatures (20℃-60℃), but if the supersaturated solution of sucrose is continuously heated (120℃-140℃), the viscosity will increase rapidly, thus becoming a syrup with a certain viscosity. At this stage, except for the change in viscosity, the other sensory physical properties of the supersaturated solution of sucrose have not changed.

Sucrose has strong crystallinity, and its supersaturated solution will have sucrose crystals precipitated after the water evaporates, which is what we commonly call "returning sand". When the syrup has not completely crystallized, add hawthorn and stir-fry continuously, and a layer of white frost will appear on the surface of the hawthorn, which is what we often call hawthorn snowball.

Then my friends, you must be wondering at this time, how did the white "frost" get there?

It starts with crystallized sugar bubbling into syrup. The crystallized sugar absorbs a lot of water. When the outside air suddenly becomes dry, the water will be released again. The crystal particles of sugar are saturated and precipitated and arranged in a regular pattern, forming a layer of white "frost" on the surface of the candy, which looks like sand, hence the name "returning sand".

If we do not turn off the fire and continue to boil the sugar, the color of the syrup will change slightly, and dense foam will appear on the surface of the syrup. At this time, the temperature of the syrup is already very high. At this time, put the skewered hawthorns into the syrup and roll them. The syrup will adhere to the surface of the fruit and air-dry, and you will get crystal clear candied haws. There are no complicated principles in this process, and the syrup solidifies to form a relatively hard shell.

If the syrup is further heated, the viscosity will continue to increase. At this time, the syrup is between the highest boiling point of the sugar aqueous solution and the lowest melting point of the impure crystalline sugar, and its temperature is about 150 degrees Celsius. When we scoop up the sugar liquid from the pot, it will appear as filamentous sugar flocs. At this time, we can make dishes such as the candied sweet potato that we are very familiar with.

When the syrup is heated to this stage, it becomes more important to control the heat, because the temperature range for producing "pulled sugar" is generally between 150 degrees Celsius and 160 degrees Celsius. When the temperature exceeds 160 degrees Celsius, the color of the syrup will quickly darken and become an extremely thick and gelatinous burnt brown, which is what we often call "caramel".

Unexpectedly, starting from solid state, sugar’s “journey” is so rich. Different temperatures create different delicacies. It really has “72 transformations”, and each one is a wonderful incarnation!

Are you eager to try it just by watching the whole process? Hurry up and go to "Kitchen Tour" to try it yourself! Watching the sugar change in the pot, the color changes from light to dark, and then cooking a delicious dish with "color, fragrance and taste" by yourself, it is simply a kind of enjoyment! What kind of food made with sugar do you like the most? How is it made? Welcome to leave a message in the comment area! It would be best if you can leave a recipe so that Fat Ke can also have a chance to try it!

Creative team: China Science and Technology Museum New Media Team

Review expert: Sun Yafei, Ph.D. in Chemistry, Tsinghua University