• Sara Thompson

The Science of Candy and Sweets

By Sara Thompson

Special to the Enterprise


During the holiday season candy and treats are made at home or bought in stores. Many of these yummy treats have precise and interesting science behind them. Confectioners and bakers need to constantly monitor the temperature their treats are cooking at or risk ruining it. Some the preciseness and what goes into some candies is very similar to chemistry.


The first step of any candy is to dissolve sugar in water while it’s boiling. When boiling the sugar syrup, the solution will pass through several stages, called candy stages, that produce specific types of candies. The longer the boiling time and the higher the temperature, the higher the sugar concentration becomes, due to the water being boiled out of the solution. The names of the stages are based on the tests used for each stage. Thread stage occurs between 230-235o F, and sugar concentration is around 80%, when put in water the solution forms a small, liquid thread. Next is soft-ball stage, ranging in temperature from 235-240oF, sugar concentration is around 85%, when dropped in water the substance forms a soft, malleable ball. Firm-ball stage is between 245-250oF, sugar concentration is around 87%, and when dropped in water the substance would still form a malleable ball, but not as soft as the previous stage. Hard-ball stage is between 250-265oF, sugar concentration is up to 92%, and when dropped in water a hard ball is formed that takes some effort to squish. Next is soft-crack stage, this happens between 270-290oF, sugar concentration is 95%, and forms solid, flexible threads. Hard-crack stage occurs between 300-310oF, sugar concentration is around 99%, and makes hard, brittle threads when dropped in water. Beyond this the sugar concentrations are 100%, but the sugar molecules begin to break down and can begin to burn if not watched or treated properly.


Many different candies can be formed in the stages mentioned earlier. The thread stage is great for glazes and drink sweeteners. Soft-ball stage is where most fudges are formed. Firm-ball stage is best for soft caramels. Hard-ball stage is great for marshmallows and rock candies. Soft-crack stage is where saltwater taffy and butterscotch if formed. Hard-crack stage is best for toffees and brittles. When candies reach these stages confectioners can add things to the candies. Gelatin is added to the sugar solution at hard-ball stage to make gummy candies. Citric acid can be added to make candies sour and tart. Cinnamon or capsaicin can be added to make hot and spicy candies.


Science can be found anywhere, even candy making. Sugar syrups need to be constantly watched to make sure they are removed from the heat at the correct temperature, or risk entering the next candy stage. Confectioners usually use a candy thermometer to help them keep track of how hot their boiling solution is, and which stage it is in. Candy is based on precision just like any type of science.

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