Crystallization in Candy-Making
Sugar is what makes our favorite cakes and cookies sweet, but there’s more to sugar than how it tastes. To make many types of candy, you start by dissolving sugar in boiling water to make a syrup. If you use more sugar than water, as the syrup cools, sugar crystals can begin to form — this process is called crystallization.
What is Crystallization?
Crystallization happens in nature when a liquid cools and begins to harden. As it hardens, molecules in the liquid join together, creating a repeating pattern that forms the crystals. Sugar crystals form when you create a supersaturated solution of sugar and water — that just means there's more sugar than can be dissolved in the boiling water — and let it cool. As it cools, the sugar comes out of the solution and forms crystals.
How is Crystallization Relevant to Baking?
Crystallization is chemistry, and the process is used to make all types of different candies. Marshmallows, gummies, fudge and rock candy are all made using crystallization — centuries before we even understood the science behind it. Sugar crystals show us an important lesson in chemistry (and baking): It’s not just about the ingredients you combine, but also the way you combine them.
Depending on how long the crystals have to form and how you handle the syrup as it cools, you can make sugar crystals in a variety of textures, shapes and sizes. For Rock Candy, the syrup is left to cool for several days to form large, impressive sugar crystals.
Where Can I See Crystals in Everyday Life?
Snowflakes, diamonds, quartz, and, of course, rock candy!