How does popping candy work?

Discover the science behind this sweet’s sizzling sensation

(Image credit: Future PLC)

Popping candy explodes on the tip of your tongue, a sensation either loved or loathed by those with a sweet tooth. The secret to its unique fizz, crackle and pop is actually all down to how it is made. In fact, popping candy is created in a similar way to traditional boiled sweets. 

Sugar, corn syrup, water and flavouring are all mixed together and then heated so that the water boils off. If the resulting sugar syrup solution would be left to cool at this stage, you’d end up with regular hard sweets. But in order to give the candy its unique popping potential, the molten mixture is exposed to high-pressure carbon dioxide gas at about 40 times atmospheric pressure. This causes small bubbles of gas to form within the solution. 

(Image credit: Future PLC)

As it is then cooled, the pressure is released, causing the candy to shatter into small pieces of rock. However, each piece still contains tiny high-pressure bubbles. When you then place the candy on the tip of your tongue, and it begins to melt, the trapped pressurised bubbles are released, creating a unique sizzling sound and the sensation of it bursting and bouncing around your mouth.


This article was originally published in How It Works issue 71


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