How to Make Homemade Rock Candy

Rock candy

The Spruce Eats

  • Total: 35 mins
  • Prep: 15 mins
  • Cook: 20 mins
  • Forming: 144 hrs
  • Yield: 4 candies (4 servings)

Rock candy is easy to make at home, it tastes great, and it's a fun recipe to do with kids. Better yet, it doubles as a science experiment because you get to watch the sugar crystals grow. It's also an excellent opportunity to get creative in the kitchen because the color and flavoring combinations you can create are endless.

This is one of the simplest sugar candies you can make, though it does require patience. All you need is sugar and water and a few basic materials you likely have around the house. Most of the steps involve making the sugar syrup and preparing the sticks and jars. While you should start to see changes within the first few hours, it may take 3 to 7 days for the rock candy to form.

Keep in mind that the exact quantity of sugar syrup you will need depends on the size of jars you're using and how many candies you want. For example, the recipe's measurements work for four 12-ounce jars or one quart-sized Mason jar. You can easily double or triple the recipe and make more rock candy at once.

1:15

Click Play to See This Pretty Rock Candy Recipe Come Together

Ingredients

  • 2 cups water
  • 6 cups granulated sugar
  • Optional: 2 drops food coloring
  • Optional: 1/2 to 1 teaspoon flavoring extract or oil

Steps to Make It

Note: While there are multiple steps to this recipe, this homemade rock candy is broken down into workable categories to help you better plan for preparation.

Prepare Your Materials

  1. Clean the glass jars thoroughly with hot water. 

  2. For each jar, use a wooden skewer that hangs about 1-inch from the bottom of the jar. Use clothespins that are balanced across the top of the jar to hold the skewer in place.

Make Your Rock Candy

  1. Gather the ingredients.

  2. Wet each wooden skewer with water and roll it in granulated sugar. This base layer gives the sugar crystals something to grab when they start forming. Set these aside to dry while you prepare the sugar syrup.

  3. Place the water in a medium-sized pan and bring it to a boil. Begin adding the sugar, 1 cup at a time, stirring after each addition. You will notice that it takes longer for the sugar to dissolve after each cup you add. Continue to stir and boil the syrup until all of the sugar has been added, and it is completely dissolved. Remove the pan from the heat.

  4. If you are using colors or flavorings, add them at this point. When using an extract, add 1 teaspoon of the extract; for flavoring oils, only add 1/2 teaspoon. Make sure you don’t stand right in front of the pan because the scent can be very strong as it rises in the steam. Add 2 to 3 drops of food coloring and stir it in to ensure an even, smooth color.

  5. Allow the sugar syrup to cool for 20 to 30 minutes.

  6. Quick rinse the prepped jars with hot water, then pour the syrup into them.

  7. Lower one sugared skewer into each jar until it hangs about 1-inch from the bottom.

  8. Carefully place your jar in a cool place, away from harsh lights, where it can sit undisturbed. Cover the top loosely with plastic wrap or a paper towel.

  9. You should start to see sugar crystals forming within 2 to 4 hours. If you see no change after 24 hours, try boiling the sugar syrup again and dissolve another cup of sugar into it. Then pour it back into the jar and insert the string or skewer again.

  10. Allow the rock candy to grow until it is the size you want. Don’t let it grow too large, otherwise, it might start growing onto the sides of your jar.

  11. Note that a top layer of crystal will form. This is okay. Once the candy has reached the desired size, break that top layer of crystal up with a fork before removing the candy.

  12. Transfer the rock candy to an empty jar or glass (keep the clothespins to balance it) and allow it to dry for 1 to 2 hours, then enjoy or wrap in plastic wrap to save for later.

  13. Serve and enjoy.

Tips

  • You can use either oils or extracts for flavor. The 1/2 to 1 teaspoon measurements for flavoring extracts that are provided create a mild-flavored rock candy. If you'd like a more intense flavor, carefully taste test the syrup in the pan and add 1/2 teaspoon extract or 1/4 teaspoon oil more to your liking.
  • Paste or gel food coloring tends to create richer colors than liquid options. Keep in mind that the color of the rock candy will be significantly paler than the syrup. If you'd like to create a deeper color, use more food coloring, preferably of the gel variety.
  • Heat is an important factor in crystal formation. Don't forget to transfer the syrup to warm jars before it cools off too much.

Favorite Rock Candy Flavors

Use any flavor and coloring combinations you like. You can go with an obvious combination such as purple for grape rock candy or do something totally off the wall and make the flavor a surprise.

  • Raspberry extract with blue food coloring creates a fun and delicious blue raspberry rock candy.
  • Cinnamon oil with red food coloring is fun for the winter and a fantastic treat or gift for the holidays.
  • Peppermint extract with a blue-green food coloring combination is always a delight. Any other mint flavoring is great as well; wintergreen and spearmint extracts are readily available.
  • Banana oil with yellow food coloring is always a hit with kids.
  • Maple extract creates an old-fashioned rock candy that doesn't necessarily need any coloring.
  • Other options include star anise for the taste of black licorice (purple), tutti-frutti (orange or pink), green apple (green), buttered rum flavoring (orange), cherry (red), grape (purple), or any other fun flavoring you find. Pair these with different colors, and you will have a rainbow of flavorful rock candy to share.

Can a Popsicle Stick or String Be Used for Rock Candy?

A wooden skewer or popsicle stick are both good options for rock candy. They're easy to work with and make removing the candy a little easier if it gets stuck to the bottom crystals. You can also use a cotton string but need to tie it to a weight of some kind or it will float in the syrup. While a paper clip is a common solution for this, a hard candy with a hole in the middle (e.g., Life Savers) is a food-safe alternative that works just as well.

Can Rock Candy Be Made in a Plastic Cup?

Glass is recommended because it is a relatively nonporous material that will produce better crystals. Foam cups and some plastic cups are more porous and may attract the sugar crystals away from the skewer, which is where you want them to grow. Some people have had success with plastic cups, so it is worth experimenting with your options.

What's the Best Sugar for Rock Candy?

Regular white granulated sugar seems to be the best for making rock candy. In some informal experiments, people have found that it produces larger crystals than other types of sugar. It's also the least expensive option, which is an important consideration because you need a lot of sugar to make rock candy.

What's the Best Way to Clean Jars After Making Rock Candy?

The crystals will grow on the bottom and sides of the jar and they're pretty tough to remove. Rather than toss glass jars, they can be cleaned up and used again. Begin by dumping out all of the syrup and any lose sugar crystals. Fill the jars with hot, soapy water and place them in a pan with about 3 inches of water. Boil the water for 10 minutes (for safety, watch it carefully as you would when canning), then turn off the heat. Let the jars cool to the touch and use a fork to break up the sugar crystals. Discard the sugar and wash the jars as normal.