Whether you need rock candy as a decoration for a baking project or as a fun-and-easy kid-friendly project for a rainy day, making rock candy is a snap. Kids love watching the sugar crystals grow, and the project doubles as a science lesson on nucleation, the process whereby atoms and molecules build on each other to form lattice structures for strength. With a couple of simple ingredients that are probably already in your pantry and a little patience, you can create sugar crystals in about two hours. To make your rock candy more exciting, add extract flavoring and food coloring.
Making a Fast Rock Candy Sugar Solution
To make homemade rock candy, begin by boiling 2 cups of water to make a simple syrup. Add granulated white sugar, 1/4 cup at a time, into the hot water, stirring until the sugar dissolves, until you’ve added a total of approximately 3 cups of sugar. Continue adding sugar until the sugar doesn’t dissolve and amasses at the bottom of the bowl, which is the point of saturation for the water. Feel free to add food coloring or flavoring exacts as well. Remember to start with just a few drops at a time.
Preparing and Filling the Jars
Use cotton string taped to a pen balanced across the lip of a clean, glass Mason jar, hanging it far enough that it almost touches the bottom. For rock candy sticks, use wooden dowels held in place by a clothespin balanced over the lip of the jar. Wet the string or dowel with water and coat in granulated sugar before placing them in a hanging position inside the jar.
After allowing the boiled water and sugar simple syrup mixture to cool for 10 minutes, pour some of the mixture into each of the prepared jars. Pour enough to cover the bottom and to barely reach the tip of the string or wooden dowel, which should not be submerged. Replace the string or dowel in the jar and cover with a wet paper towel or loosely wrapped plastic cling film. Place the jars in a cool, shaded area. Sugar crystals should begin to grow within 2 to 4 hours. If not, boil the mixture again while adding another cup of sugar to the mixture.
Harvesting the Sugar Crystals
Once you’ve grown as many sugar crystals as you want, remove the string or dowels from the jars. Allow the sugar crystals to dry slightly before eating or using them for decoration. If you prefer to use loose sugar crystals, simply brush the crystals from the string or wooden dowel before allowing them to dry. For thinner crystals, separate the blocks of crystals and spread them into a single layer to dry before using them for garnishing or eating.
Tips for Success
Make sure the Mason jars are completely clean before pouring the simple syrup mixture in them to avoid growing any kind of mold within the candy. The simple syrup itself should be completely saturated with sugar for the best results. If you don't have enough sugar in the water and sugar mixture, crystals will grow more slowly or may not grow at all.
If you use flavored extract, add no more than 1 to 2 teaspoons. If using essential oils, however, use half the amount as the flavor will be even stronger than the extracts’ flavors. Try using an array of flavors: lemon, cherry, vanilla, coconut, cinnamon, orange or strawberry. Remember to begin small with food coloring as well, adding ½ teaspoon to start and two to three drops at a time to deepen the color.