The Science of Candy

By: Deeana Saminathan, SPECTRUM Writer


       Have you ever wondered how candy is made? How about how it’s able to stay fresh well past Halloween? While candies come in all shapes and textures: chewy like fudge, fluffy like cotton candy, hard like a lollipop and crunchy like rock candy, the method to making these different types of candies follow a similar chemical process (The Sweet Science of Candy making, 2014-2015).


       Sucrose is the main component of candy. It is both a carbohydrate and a disaccharide, composed of both glucose and fructose. Intermolecular forces are important in dictating the state of sugar, through mediating the attraction between sucrose molecules. When granulated sugar is mixed with water, a partial number of sucrose molecules separate from each other due to their attraction to the water molecules via intermolecular forces.


       To make candy, sugar is first heated to a high temperature so that it melts . The scalding solution is then then cooled into a solution that is supersaturated. The supersaturation is considered unstable, forcing the sugar molecules to crystallize into a solid. The melting process can then be observed when the temperature is increased, causing more sugar to dissolve in water and vice versa. Later, in the cooling process of this solution, due to the formation of chemical bonds that releases energy, more sucrose molecules join in crystal formation (The Science Behind Halloween Candy). The sugar crystals that we observe are due to the arrangement of these sucrose molecules in repetitive patterns extending all three dimensions.


       Depending on how this crystallization process is carried out, we can see different forms and sizes of candies. For example, when making rock candy, the syrup is cooled down slowly over many days, while in making fudge, the solutions is stirred on an ongoing basis after the primary cooling period. This constant stirring, is used to prevent large sugar crystals from forming (Science of Candy: What is Sugar? | Exploratorium).


       Conversely, to make cotton candy and glass candy, the syrup is cooled quickly to prevent crystallization. For cotton candy, the melted granulated sugar solution is sprayed for immediate solidification, while for glass candy, the candy stays in a non-crystalline structure after forming. For fluffier gummies and marshmallows, gelatin is added to the sugary solutions, giving either a rubbery or a fluffy consistency when whipped (Science of Candy: What is Sugar? | Exploratorium).


       We can also introduce other types of candies into the mix by adding other ingredients! Adding fatty ingredients like butter, is crucial in making toffee, where the presence of fatty ingredients prevents crystallization from occurring. This gives the candy its smooth texture and the flexibility. Similar candies include brittles, butterscotches, caramels and taffies (The Sweet Science of Candy making, 2014-2015).


       With all this in mind, candy companies spend a collasal amount of money on on research for how to improve  their candies! Did you know that candies are created two years prior to the selling date according to the Hershey Company? (Halloween candy Expire, 2017) One of the important properties that they consider are shelf life, also known as the best before date. To extend the shelf life of candies, manufacturers work on many aspects such as changing the time and temperature in which the candy is made, adding ingredients such as antioxidants to avoid oxidation as well as the roasting of nuts that are incorporated within chocolates to prevent oxidation. Manufactured sweets such as caramels, candy corn, jelly beans, and gum can last from six to nine months while chocolate and hard candies can last up to a year. If you want to make your chocolate last longer, a quick tip would be to try freezing your chocolate candy. The frozen chocolate candy is just as delicious, as it provides a crunchy taste and slowly melts in your mouth. To conclude, while candy is delicious, watch your sugar consumption because too much of anything can be bad for your health (Halloween candy Expire, 2017)!


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“Science of Candy: What is Sugar? | Exploratorium.” Exploratorium: the museum of science, art and human perception,


“The Science Behind Halloween Candy.” Science Meets Food, 4 Oct. 2016,


“The Sweet Science of Candymaking.” American Chemical Society,

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