Learning how to make rock candy at home was a total game-changer for me. It’s such a fun and special treat to share with my friends and family on special occasions. I chose to make raspberry-flavored blue rock candy, but you can make any color or flavor you like with this quick and easy rock candy recipe!

Shards of blue colored candy in a bowl.

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With my easy recipe, you’ll learn how to make rock candy sheets quickly and easily. It’s a fast way to make it, and you can make any color or flavor with this method. There’s no need to wait for days and days when you can make delicious blue rock candy in just 20 minutes!

What’s in This Rock Candy Recipe?

  • Water: Helps to dissolve the sugar into solution.
  • Light Corn Syrup: Helps prevent sugar crystallization. It contains glucose, which interferes with the formation of large sugar crystals, resulting in smoother and smaller sugar crystals that are characteristic of rock candy.
  • Granulated Sugar: This is the main ingredient that will form the candy. As the sugar solution cools and evaporates, the sugar molecules come together and form crystals.
  • Flavoring Extract: I used raspberry, but you can use just about any flavor!
  • Food Coloring: I used blue, but feel free to choose any color or leave your candy plain. Both water and gel food coloring will work.
Overhead view of shards of blue colored sugar glass.
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Tips for Success

  • You can choose any color and flavor combination you like! Try green candy for St. Patty’s Day (with lime or sour flavor), orange and black for Halloween, or red with strawberry flavor for Valentine’s Day. The possibilities are endless!
  • Temperature is super important! You’ll need to bring your sugar to the hard crack stage, which is 300°F; otherwise, it will not harden.
  • If your candy doesn’t harden, even after sitting for a long time (it should only take 45 minutes, not much longer), it might be that your liquid never got hot enough. It’s important that the temperature reaches 300°F while cooking the syrup. And the best way to make sure it gets hot enough is to use a candy thermometer to check. This is not the time for guessing!
  • To turn the sheet of candy into small pieces, it’s easiest to use a metal mallet (like a meat tenderizer). Just hit the sheet with it until it breaks into pieces. If you want to make it look more like rock candy, place those pieces into a bag, and use a rolling pin to crush them up even smaller.

How to Store

Store leftover rock candy in a Ziplock bag at room temperature for up to 1 month. Keep it in a cool, dry place. I had a reader comment that a great way to keep the pieces from sticking together is shaking them in powdered sugar before sealing them in an airtight container. Genius!

Broken pieces of blue sugar candy.

Serving Suggestions

Serve this tasty candy with a fun and colorful drink or cocktail, like lavender lemonade, cherry limeade, blue margaritas, a blue Hawaiian, or a cotton candy martini!

5-Star Review

“Just made this! And it is awesome and so easy! I will actually use this rock candy as the gems in my geode cake later this week! I used lemon extract in mine and it is delicious! Thank you!!” – Lauren

Recipe Card

How to Make Rock Candy

4.48 from 99 votes
Prep: 10 minutes
Cook: 10 minutes
Total: 20 minutes
Servings: 8
Author: Becky Hardin
blue rock candy in a bowl
Rock candy is such a fun treat to make and eat for holidays, parties, or any fun occasion. Learn how to make rock candy at home (fast!).
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Ingredients 

  • ½ cup water 114 grams
  • ¾ cup light corn syrup 234 grams
  • 2 cups granulated sugar 400 grams
  • 2 teaspoons flavoring extract 8 grams (I chose raspberry, but there are lots of flavors to choose from!)
  • Food coloring optional (I used blue, but use any color!)

Instructions 

  • Mix all ingredients together in a medium saucepan set over medium heat.
    ½ cup water, ¾ cup light corn syrup, 2 cups granulated sugar, 2 teaspoons flavoring extract, Food coloring
  • Stir until boiling. Once the liquid begins to boil, do not stir until finished.
  • While the candy comes to a boil, line a baking sheet with aluminum foil and spray the foil with nonstick spray. Set aside.
  • Once boiling, place a candy thermometer in the liquid and monitor closely. when the liquid reaches 300°F, take off the heat and set aside.
  • Allow the mixture to cool until the bubbles quit breaking at the surface of the liquid.
  • Pour liquid onto the prepared baking sheet.
  • Allow to cool until fully hardened. Then, break apart to the size desired.

Becky’s Tips

Storage: Store rock candy in an airtight container at room temperature for up to 1 month. Keep away from heat and humidity.
Calories: 283kcalCarbohydrates: 74gFat: 0.2gSodium: 21mgPotassium: 1mgSugar: 74gCalcium: 5mgIron: 0.03mg

Nutrition information is automatically calculated, so should only be used as an approximation.

Did you make this? Leave a comment!

More Candy Recipes to Try!

Meet Becky Hardin

Becky Hardin is a wife and mother living in Saint Louis Missouri. She founded The Cookie Rookie in 2012 as a creative way to share recipes. Now, she is a trusted resource for easy cooking around the world, being featured in Taste of Home, The Kitchn, ABC’s Home and Family, and more. Here at The Cookie Rookie she is the editor in chief of all recipes and continues to enjoy sharing her passion for cooking for busy families. She has since founded two additional food blogs, Easy Chicken Recipes and Easy Dessert Recipes.

4.48 from 99 votes (79 ratings without comment)
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65 Comments
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Mrs. Adams
Mrs. Adams
September 27, 2024 9:08 pm

Tried this recipe using lemon and orange. Only had the slightest hint of flavor. IF I try it again, I will be doubling the flavor extract.2 stars

Samantha Marceau
September 30, 2024 9:30 am
Reply to  Mrs. Adams

Hi Mrs. Adams, we’re sorry to hear this recipe didn’t work out as expected! What brand of flavoring did you use? We recommend something strong, like LorAnn, for the best flavor. You may have to adjust depending on your personal preference, though!

San
San
September 20, 2024 9:44 pm

I love the way you wrote out the directions and thank you for the pictures. My question before I get going on this is what would happen if I stored it for longer than a month? I’ve heard other people say that it can be stored for up to a year. We’re heading into October and I’d like to get going on Christmas projects. So, would 3 months be too long to store this recipe?5 stars

Samantha Marceau
September 23, 2024 10:22 am
Reply to  San

Hi San, 1 month is our recommendation, but it will probably keep for longer so long as it’s kept in a cool, dry place.

Morgan
Morgan
March 12, 2024 1:48 pm

this worked for me as a scenic fair project it worked because I am doing rock candy and it worked really good for me but I am a special ed kid I work better with a video as well so I know what you mean and talk about.5 stars

Samantha Marceau
November 27, 2023 8:39 am

Hi Kevin, flavoring extracts and oils are very different! I would recommend using only a drop of oil, as it is much, much stronger than an extract!

Nina
Nina
September 23, 2023 10:02 am

The rock candy became great.The only problem that I can’t explain is why it turned green when I put blue color.The first ones were blue but the next were pure green.

Samantha Marceau
September 26, 2023 9:58 am
Reply to  Nina

Food coloring can be tricky! It’s likely that the sugar caramelized more between the first batch and the second, which adds a yellowish pigment to the candy that combines with the blue to produce green!

Ronin
Ronin
July 10, 2023 5:01 pm

I made this today and by the time it got to 300 it was burnt and tasted like ginger(I made lemon), it could be because I used agave instead of corn syrup. Do you think this is the cause?3 stars

Samantha Marceau
July 12, 2023 9:05 am
Reply to  Ronin

More than likely! It’s very important to use corn syrup, as it behaves differently than agave!

Katie Lindfors
Katie Lindfors
March 23, 2023 3:49 pm

It might be because I used Dark corn syrup by accident, and because I used vanilla to flavor it, but my rock candy don’t taste great. It sticks to my teeth and tastes gross, but I admit, it might be because of me.3 stars

Samantha Marceau
March 23, 2023 4:40 pm
Reply to  Katie Lindfors

We do think dark corn syrup could be the culprit here! It imparts a much stronger molasses-y flavor which can become unpleasant and even bitter. As for the stickiness, make sure you’re using a properly-calibrated candy thermometer and getting the sugar up to 300°F (the hard crack stage). It sounds like your sugar may have only made it to the soft crack stage!

christine
christine
December 4, 2022 2:37 pm

First attempt and I think they came out great! Sadly didn’t realize I didn’t have more sugar on hand and only made 3 flavors – watermelon, root beer, and cherry and then ran out. Next time I’ll make grape and peppermint, and maybe raspberry! Cheap candy thermometer off Amazon worked like a charm!5 stars

Hard Rock Candy.jpg
Samantha Marceau
December 5, 2022 9:24 am
Reply to  christine

Wow, that looks perfect, Christine!

Nick Detloff
Nick Detloff
November 29, 2022 11:00 am

After cooled, rock candy is not sticking together, but doesn’t crunch the way I remember when I was a kid. It gets stuck in my teeth and has been kind of not fun eating it. Any tips to making this crunchier? Temp came up to 300 and reached the crack stage.

Samantha Marceau
November 29, 2022 1:32 pm
Reply to  Nick Detloff

Hmm, it sounds like a humidity issue. Sometimes if your kitchen is humid, not enough water cooks off and the candy can set a bit soft. I would try reducing the water in the recipe to 1/4 cup and make sure to let it cool at room temperature, not in the refrigerator!

Emily
Emily
November 22, 2022 3:30 pm

Made this today and the kids love it.. I personally will add more flavoring last time as I made strawberry and it’s kind of bland5 stars

received_1084931155522709.jpeg
Samantha Marceau
November 22, 2022 4:28 pm
Reply to  Emily

We’re sorry this didn’t turn out quite as you hoped, Emily! Hopefully the next batch will be better with more flavoring. It looks great!