Homemade Rock Candy
Overview
Turn a solution of sugar and water into candy and learn some chemistry in the process!
Supplies Needed
Materials
3 cups of sugar
1 cup of water
Either food coloring/flavoring or Kool-Aid
Clean string and dowel rod or wooden skewer
Pot
Wooden spoon
Heat source (stovetop, microwave, cooktop)
½ pint Mason jar or other heat resistant container
Rock Candy Process
It is important to setup your supplies before you get started. For each rock candy that you want to make, you will need one clear glass or cup to monitor your progress in. It is also a good idea to have some clothes pins that you can use to hold up your rock candy like so. We want to make sure that the stick is submerged in the mixture but not touching the sides of the bottom of the cup/container because the crystals could attach to both the stick/string and the container and we wouldn’t be able to get it out.
After properly setting up your area, we need to do two more things for preparation.
- The first is we will need to dip our stick or string into water and then roll it in sugar. This will give the sugar mixture that we create in our cup a base to build off of.
- The second part is to prepare our rock candy sugar mixture. Whether you want to do kool-aid as flavoring or add a flavoring like this one and some food coloring, we need to start by making a supersaturated sugar base. The way our rock candy is going to form is by evaporation. We will take 3 cups of sugar and dissolve that with one cup of water by heating this mixture until boiled. Once you see the sugar dissolve and make a simple syrup, we will add in our flavoring of choice, mix well and let it cool for about ten minutes before finishing the rest of our project.
Once the mixture is cooled down a little bit, we will pour it into our cup and using clothespins to brace the string or skewer, gently lower our pre-sugared stick into the mix. We want to make sure that a good 4-5 inches of our string/skewer is submerged in the sugar mixture.
When we boiled the sugar and water together, we made what is called a supersaturated solution. The increased temperature increased the solubility of our solid (sugar) in our liquid (water). As the temperature cools back down and water begins to evaporate out of our container, the sugar makes crystal molecules which will attach to our stick our string. The longer we leave it in the container, the more sugar molecules that will attach to our container. I would recommend giving your rock candy at least 4-7 days at room temperature to grow its crystals. Make sure to monitor it so that it doesn’t grow attached to crystals at the bottom or sides of the container.
After you reach the desired size of your candy, you will want to gently raise the candy out of the mixture, and suspend it over another cup/container to allow and of the mixture that has not crystalized to drip off your candy.
Instructional Video