The Accidental Scientist: Science of Cooking

What’s Going On?


Why do I add corn syrup?
Corn syrup acts as an "interfering agent" in this and many other candy recipes. It contains long chains of glucose molecules that tend to keep the sucrose molecules in the candy syrup from crystallizing. Lots of sucrose crystals would results in grainy caramels.

In this recipe, the cream and butter also act as "interfering agents"—the milk proteins in both help to prevent crystal formation.


Why do I need to stop stirring after the syrup begins to boil?
At this point, you have dissolved the crystal structure of the sugar. Stirring or other agitation is one of the many factors that can encourage the fructose and glucose molecules in your syrup to rejoin and form sucrose—crystals of table sugar.


Why should I wash down the sides of the pan?
The sugar crystals are dissolved at this point in the process. But a single seed crystal of sugar clinging to the side of the pan might fall in and is another factor that can encourage recrystallization.


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