The Real Reason Cotton Candy Is So Fluffy

No matter what age you are, there's just something so magical about eating cotton candy. It's as fun to look as it is to eat, and the way the fluff melts as soon as it hits your tongue is an experience in itself. If you've ever seen a cotton candy vendor actually make the classic carnival treat from scratch, you know that it only takes one ingredient: sugar. Sugar exists in many forms, including in crystals, in syrup, in powder, but cotton candy in comparison is drastically different from its original state. 

How is it that after a few rotations in a special machine, sugar becomes fluffy? According to one particular episode of Food Network's "Unwrapped" (via YouTube), it's a combination of both physics and chemistry. In the episode, it is noted that in order for the sugar to become cotton candy, it has to reach 300 degrees Fahrenheit. First, sugar is emptied into a rotating tub that spins the sugar at a high rpm. As the sugar spins, it's also being melted. Once the sugar is well-over 300 degrees hot, it's forced through a screen with tiny holes, creating delicate strands of sugary floss. As the machine continues to spin, the floss accumulates and becomes fluffy.

Why does cotton candy lose its fluffiness over time?

When you combine food and heat, the effects are usually permanent. After all, you can't un-cook an egg, or un-bake a pie. But despite the fact that the process of making cotton candy involves heating sugar to over 300 degrees, it doesn't stay fluffy forever. The reason, Candy Turf explains, has to do with the natural properties of sugar. Sugar is hygroscopic, so whether in the form of crystals or cotton candy, it attracts and absorbs moisture. When heated in a cotton candy machine, sugar doesn't lose its hygroscopic properties, and that means it will melt whenever it's exposed to moisture. 

In the same way that cotton candy melts in your mouth when your saliva comes in contact with it, it also melts when it's left out for too long. If there's any humidity in the air, the sugar will absorb the ambient moisture, causing the cotton candy to de-fluff. That's why, according to Spun Paradise, unopened cotton candy, or cotton candy stored in an airtight container, can last up to 10 weeks, while the cotton candy you buy at the state fair will lose its fluffiness in as little as 10 minutes.