How to Grow Rock Candy Crystals

Rock candy crystals are an alternative to sugar cubes.

Rock candy crystals, created via the recrystallization of pure cane sugar, provide a tasty confection for people of all ages, as well as a novel sweetener for coffee and tea in upscale restaurants and hotels. Creating and growing your own rock candy crystals involves time and patience, as it is not a process that occurs overnight.

Things You'll Need

• 2 cups of water
• Medium-size saucepan
• Stove
• 4 cups of sugar
• Wooden spoon
• Small, clean glass jar
• Funnel (optional)
• Waxed paper
• String
• Scissors
• Metal screw or washer
• Pencil

Instructions

1. Pour two cups of water into a medium-size saucepan, and place the pan over medium-high heat until lightly boiling. Bubbles should be breaking on the surface of the water.

2. Measure and pour four cups of refined white sugar into the boiling water. Stir continuously with a wooden spoon until the solution turns clear and the sugar is completely dissolved. Continue stirring the water and sugar solution until it reaches a rolling boil. Remove the saucepan from the burner. A rolling boil occurs when countless bubbles are breaking rapidly on the surface of the water.

3. Pour the heated solution directly from the pot into a small glass jar. Place a heat-resistant funnel over the opening of the jar to facilitate pouring, if needed.

4. Cut a piece of string with scissors that is about two-thirds of the height of the jar. Use the jar as your guide by holding the string next to it and determining where to cut it.

5. Tie a metal screw or washer to one end of the string, and tie a pencil to the other end. Ensure that the knots that you make are secure.

6. Dip the string, weight end first, into the sugar solution in the jar to saturate the string. Remove the string from the jar and cover the mouth of the jar with a piece of waxed paper. Place the saturated string on a piece of waxed paper. Straighten the string and leave it to dry on the waxed paper for about 72 hours.

7. Remove the wax paper on top of the glass jar. Pick up the string from the waxed paper with the pencil. Suspend the string, weight end first, into the jar and saturate the string once again with the sugar solution. Let the pencil rest in a horizontal position across top of the jar mouth to hold the string in place. Allow the string to remain suspended in the jar for about seven days at room temperature.

8. Monitor the growth of the rock candy crystals throughout the course of the prescribed seven-day period. You should be able to see the shape of the crystals change. At the end of seven days, remove the string from the jar, and use the crystals as you wish by gently breaking them off of the string with your fingers.

Tips & Warnings

• Add two to three drops of food coloring to the sugar solution during cooking for colored rock candy.

References

• Exploratorium: Rock Candy Recipe