Popping candy is a confection known for the crackling sound and tingling feeling it creates in the mouth. The science behind this phenomenon involves embedding a common gas into a solid sugar matrix under extreme conditions. This article explains the steps that create this fizzy treat and the physics governing its energetic release.
The Manufacturing Process: Infusing the Gas
Popping candy starts like other hard candies, using a mixture of sugars heated into a molten liquid. This liquid is transferred into a specialized chamber pressurized with carbon dioxide gas at approximately 600 pounds per square inch (psi). This pressure is many times greater than the pressure inside a typical car tire.
While under this immense pressure, the gas is pumped into the viscous sugar. The mixture is then cooled rapidly to prevent the gas from bubbling out. As the candy solidifies, the gas molecules become physically trapped within the hardening structure, creating a microscopic gas storage device.
The Physics of Trapped Carbon Dioxide
The finished candy is a glassy solid containing countless microscopic pockets, or vesicles, of compressed gas. Each cavity is a high-pressure vessel, maintaining the 600 psi pressure from the manufacturing environment. The hardened sugar matrix acts as a physical barrier, resisting the natural tendency of the compressed carbon dioxide to expand.
These minute, high-pressure bubbles represent stored potential energy. The 600 psi internal pressure is vastly greater than the standard atmospheric pressure outside the candy. This large pressure differential is the source of the energy, waiting for the sugar shell’s structural integrity to fail. The candy is shattered into smaller pieces after cooling, ensuring each fragment carries a high-pressure charge.
What Happens When You Eat It
The popping sensation is triggered by moisture, primarily the saliva inside the mouth. Saliva immediately begins dissolving the sugar matrix that forms the walls of the microscopic pressure vessels. As the sugar dissolves, the solid shell surrounding the trapped carbon dioxide thins and weakens.
When the sugar wall can no longer contain the internal 600 psi force, the barrier ruptures. The highly compressed carbon dioxide gas rushes out, expanding rapidly to meet the lower atmospheric pressure. This sudden expansion of gas creates the audible “pop” and the distinct crackling and tingling sensation felt on the tongue. The process repeats as each piece of candy dissolves, creating the continuous fizzing experience.