How to make interesting rock candy colors

How to make interesting rock candy colors

Rock candy, a science experiment, learning experience, and a tasty treat rolled into one can keep the young and young-at-heart happy. Easy to make, with a little guidance and supervision for the young chefs, rock candy can be a long-lasting, various colored, party favor, gift, or movie munching treat.

The following recipe and tips require boiling water on the stovetop and pouring hot liquid into jars. If spilled, very bad burns can occur so please take extra precautions and be careful.

You will need:

Clean glass canning jars or larger such as a pickle/mayo jar
Pieces of clean cotton string
Popsicle sticks, pencils, or skewers
Paper Clips
Measuring cup
Large heavy metal saucepan
Long wooden stirring spoon
Thick Pot Holders
Candy Thermometer

Ingredients for each length of rock candy:
1 cup of water
2 cups of granulated sugar
Liquid Food Coloring
Candy Flavoring (Optional)


Wash and thoroughly dry all canning or glass jars to be used. Make certain string and paperclips are also clean.

Tie one end of a piece of string around the middle of the stick, skewer or pencil. Balance over the lid of the jar and allow the string to dangle into the jar. Cut the string, if necessary, so that it is a little shorter than your jar, do not allowing it to touch the bottom.
Remove the string/skewer and moisten with a little water, then roll in the granulated sugar. Attach the paper clip on the end of the string as a weight. The string needs to hang straight. Lay the stick over the top of the jar again and place it to the side.

Place 1 cup of water into the large saucepan and heat on the stovetop until boiling. Add 2 cups of sugar while stirring. Keep stirring until the sugar dissolves. Place a candy thermometer into the mixture and continue to heat and stir until the mixture reached 240 degrees.

Remove the pan from the heat. Add two to four (or more) drops of liquid food coloring. The more drops you add the darker the color. Stir the drops into the mixture and don’t be afraid to mix colors; red and blue create purple candy, yellow and green create a pineapple-lime color, while red can come out as pink, magenta or maroon. Experiment!

Add a teaspoon of candy flavoring if desired and try variations with color versus flavoring. Red rock candy with a lemon flavor or green candy that tastes like grape.

Pour the hot mixture into the jar, allowing the string to hang through it.

Let the sugar water sit for a few days without being moved. The crystals will begin to form along the string in a few hours, but let them grow for 3 to 10 days (or more). When ready to eat, remove the candy-covered string out of the jar. Break the pieces apart and enjoy. Store leftover candy in a covered container in a cabinet; not the refrigerator. To present as a gift, leave the candy on the string but cut the paperclip from the bottom. Wrap in wax paper, tie with cascading ribbon and a homemade, very special gift is complete.


Large crystals are created from a thick sugar-water mixture. Be certain to add the whole 2 cups of sugar, or a little more, to the 1 cup of boiling water.

Allow crystals to grow for up to 10 days for the maximum size.

To create a very unique colored rock candy, fill the jars only half way with a colored mixture and allow to crystallize. After a number of days, cook up another batch and pour over the first crystallized candy. The new boiling mixture will melt the first, collide colors, and create rock candy with a marbled, speckled or very interesting color combination.

Have Fun.

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