Can you name the key ingredient in lollipops? Marshmallows? Caramel? Pez? Rock candy? Those pleasantly chalky textured mints that restaurants always put in bowls but you never really see anywhere else (and they seem kinda stale but are actually tastier that way)? If you answered “awesomeness,” you are only partially correct. All of these delicious treats (and many more) are composed primarily of sugar. The versatility of sugar’s repertoire results from its fabulously unique chemical properties.
Now that I have spouted promises of interesting explanations of sugar’s underlying scientific principles, you’re wondering, “what are these fabulously unique chemical properties that make sugar the all-star of the confection squad?” Table sugar, or sucrose, consists of two very simple molecules not unlike those that compose the backbone of our DNA. The bulkiness of the fused product of these two small monosaccharide (single sugar unit) molecules, fructose and glucose, promotes crystallization, which as I will explain below is a desirable property of some confections.
For other types of candy, this propensity for sugar crystals to crystallize out of solution is frowned upon. Thankfully, some smart candy scientists discovered that addition of acids or other ingredients to the candy mix can cleave our favorite disaccharide into fructose and glucose, freeing them from their crystal structure and allowing them to more easily dissolve into a liquid and assume a smooth transparent state. Another bonus of cleaving sucrose into its two smaller subcomponents is the wicked sweetness boost that comes from these sweet little molecules!
Sucrose
Sugar structures of confections can be generally categorized as either crystalline or the exceedingly explicit category noncrystalline. Crystalline candies, such as rock candy or Pez, are made up of individual sugar crystals that are held together by a small amount of amorphous sugar syrup (it’s not as scary as it sounds, its just basically like a really delicious sugar glue). In crystalline structures, sugars crystallize out of solution and align themselves into nice neat organized arrangements. The surest way to tell if a candy is crystalline is to hold it to your tongue. The individual crystals will be anxious to escape their strict organizational structure (everything in the universe always flows towards disorder or at least that is what I have been telling myself to explain my life’s penchant for chaos) and you will feel the candy dissolve quickly.
Most types of candies are noncrystalline, or at least partially noncrystalline, in nature meaning they are made up of sugar crystals that are dissolved into liquid. The properties of these mixtures of sugar and water are largely dependent on their moisture content and the coolest thing about these candies is that they are actually liquid. Bet you didn’t know that lollipops were technically liquid and so are caramels, marshmallow and taffy. These candies are fluid in that the sugar molecules run randomly all over the place but these liquids have a very high viscosity, meaning these liquids are thicker than the tension between the Packers and the Vikings this season.
If you still believe me, and I know sugar’s rockin’ chemistry is unbelievable, I bet you want to know the difference between hard candies and their softer counterparts like taffy and marshmallow. Hard candies have undergone a phase shift from an amorphous liquid to a glass. Now don’t get me wrong, candies in the glassy state are still liquid, since the molecules are just as random as Susan’s hatred of pandas or Carl’s love of circus peanuts, but these liquids are so freaking viscous they are basically immobilized. Candies with higher moisture content will become glass at lower temperatures than those with lower moisture, increasing the likelihood that they will not be in the glassy state at room temperature (watch out for these cause they also tend to be less stable than low moisture candy).
Next week we will look at corn syrup and how it differs from sugar.
