The first step in making most candy is to dissolve sugar2(candy’s primary ingredient) into boiling water to form a syrup. The way the syrup is cooled determines whether the candy will becrystallineornon-crystalline.3
Crystalline Candy
Crystalline candy usually has fine sugar crystals and a lower sugar concentration than non-crystalline candy. To make crystalline candy, the sugary syrup is stirred continuously as it cools to ensure the sugar crystals remain small. Fudge is an example of a crystalline candy.
Non-Crystalline Candy
Non-crystalline candy is usually hard and brittle and has a higher sugar concentration than crystalline candy. Typically, non-crystalline candy is made by allowing the sugar syrup to cool over several days. Rock candy, lollipops and glass candy are some examples of non-crystalline candy.
Fun facts: Glass candy was historically used for stunts that involved people breaking windows. Gummies are made in a similar way to glass candy, but with gelatin added to the sugar syrup to give it a rubbery consistency.
The Science of Fudge: How Fudge Is Made
The Science of Fudge: How Fudge Is MadeFudge is made by heating sugar and water to a temperature above the boiling point for water, which is 212° Fahrenheit.3The candy maker pours the syrup into a pan so it can cool faster. This technique helps prevent sucrose molecules from forming into a large crystal. Once cooled to 122° F, the syrup is stirred and scraped, forming many crystals at once. Continued stirring helps the sugar molecules spread among and bind to the crystal seeds. This helps keep the crystals small and creates the fudge’s milky texture.
More Common Candy Ingredients
Many candies also havepreservativesand other ingredients to keep them sweet and edible. The University of Hawaii’sFood Safety and Technologynewsletter article,Common Food Additives in Candy,4identifies several candy additives:
- Butylated hydroxyanisole (BHA)is an antioxidant that prevents fats and oils from becoming rancid in candies such as peanut-butter cups.
- Gum baseis one of the main ingredients in chewing gum. It’s made by blending and heating several vegetable or synthetic fibers with a softener such as paraffin and antioxidants.
- Potassium sorbateis a preservative that is the potassium salt of sorbic acid,5which is also a preservative.
Caffeine6,ascorbic acidandcitric acidare also common candy ingredients. Citric acid gives candies like lemon drops their tart flavor.
For more information about candy and its chemistry, see these resources:
