Learn how to make rock candy at home with this easy rock candy recipe and tutorial! A delicious and fun science experiment for kids that combines science and sweets! Kids love this yummy activity!
Rock Candy Recipe and Tutorial
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Learn how to make your own rock candy! Making rock candy is a clever way to combine an educational STEAM science lesson with a delicious sugary treat at the end. All it takes to make rock candy are a few simple ingredients, some basic kitchen tools, a whole lot of sugar, and a little bit of patience!
This rock candy recipe is one that your whole family will enjoy making together! It’s so much fun and SO cool to watch the sugar crystals grow!
How to Make Rock Candy
Rock candy is one of the easiest homemade candies to make, but it does take a bit of time. Depending upon the temperature and humidity of your climate, it can take anywhere from 5-10 days for the crystals to fully form.
Create a science notebook and have the kids record the changes in their rock candy crystals throughout the course of the week – it’s great fun to watch the crystals form and grow! Let the rock candy experiment begin!
Supplies Needed to Make Rock Candy:
- 6” Wooden Skewers or Candy Sticks
- Wide-Mouth Mason Jars (pints and quarts work best)
- Food Coloring
- Granulated Sugar
- Candy Flavoring, optional
- Large Pot
- Warm Water
Note: I recommend using at least a 3-Quart Saucepan for this recipe since the mixture will expand while boiling!
Rock Candy Making Tutorial:
To begin, prep the candy sticks. Soak the sticks in water and roll them in a coating of granulated white sugar to “seed” the rock candy crystals (give them a starting point to grow from). Allow the sugared sticks to dry completely (for at least 30 minutes).
If desired, use a fine-mist spray bottle to lightly mist the sticks with a second light coat of water, then roll them in a second coat of sugar, and allow to dry completely again. The better job you do of seeding the sticks, the larger and more quickly your sugar crystals will grow!
When making a batch of rock candy, the typical sugar-to-water ratio is 2 cups of granulated white sugar for every 1 cup of water, but since the overall goal is to reach a point in which the sugar solution is completely saturated, you may need more sugar than 2:1 ratio. I found that 3 cups of sugar per cup of water worked the best for creating our saturated solution.
Combine the sugar with warm water. I let my kids stir the sugar into the water until they reach a point where they can no longer dissolve any more of it. They should be able to dissolve about 1/2 to 2/3 of the sugar in the recipe, and the rest will be dissolved in the next step.
Have an adult place the saucepan on the stove and bring the sugar and water to a boil over medium-high heat. Keep the mixture at a low rolling boil and continue to add sugar one cup at a time until you can no longer dissolve any more of it. (If you’re using a candy thermometer, you’ll want the temperature to reach around 250 degrees F.) Congratulations, you now have a fully saturated solution!
Turn off the heat and allow the mixture to cool for 20-30 minutes.
Carefully pour the sugar solution into the glass jars until it is about 1″ below the top of the jar (always use EXTREME caution when pouring hot liquids!). If you’d like to add a few drops of food coloring or candy flavoring, now is the time to do so. You can use different flavors for each of the different colors or make them all single-color/single-flavor if desired.
We added our favorite colors of food coloring to the jars before adding the sugar syrup, but we opted to forego the different candy flavorings since my kids like the great taste of the natural sugar.
Slowly insert the sugared wooden sticks into the solution. You can use a clothespin as shown to keep your sticks in place. Most wide mouth jars will allow for 2 sticks to be placed in each, but be sure that the sticks are not touching the sides and/or bottom of the glass or each other! You need to leave room for the new rock crystals to grow!
Note: Make sure that your sugared sticks are completely dry! If they are too wet when you put them into the hot sugar solution, all of the seed crystals will fall off, and the rock candy crystals will not grow as easily.
Allow the sugar solution to cool to room temperature, and then place the jars in a warm, sunny location where they won’t be disturbed. If desired, you may cover the tops of the jars with a coffee filter to keep any dust out.
…and wait…and wait…and wait (still with me?)…and wait some more…
After about a week of watching the crystal growth, you will have yourself a batch of sparkling sugar rock candy! It’s completely normal for there to be a thick layer of sugar crystals at the bottom of the jar as well as a thinner layer on top of the liquid.
When the crystals have stopped growing, simply remove the sticks from the jar (you may need to wiggle them around a bit to break free of any other crystals that have grown within the jar) and enjoy!
YUM! So pretty, SO tasty, and totally worth the wait! These rock candies would make a great gift idea – especially when added to a coffee or tea gift basket!
Rock Candy FAQs
Why Did My Rock Candy Fail?
The top reasons that rock candy fails are because there wasn’t enough sugar in the solution OR there wasn’t enough sugar seeding on the sticks so the crystals didn’t have anything to grow on. Temperature can also effect the size and formation of the candy crystals, so make sure that you are bringing the solution to a full rolling boil during the cooking process. Dont’ forget that this IS science, and even if you follow all of the directions, sometimes experiments fail based upon environment factors like humidity, sunlight, and ambient temperature. It’s always worth it to attempt the experiment again, and hopefully you’ll have better luck next time!
Can I Use a Popsicle Stick or String for Rock Candy?
Wooden skewers, wood sticks, and popsicle sticks are the best options for making rock candy because they are sturdy and take the seeding process well. Cotton string may also be used, however, you will need to weigh down the end of the string which may result in the weight becoming embedded inside the rock candy crystals. Lollipop sticks may also be used, but are not recommended since they are prone to becoming soggy after soaking in the solution for too long.
What’s the Best Way to Clean Jars After Making Rock Candy?
The sugar crystals attach themselves rather solidly to the glass jars, so cleaning them can be kind of a pain if you’re not familiar with the best methods. I’ve found that the easiest way to clean them is to first soak the jars in hot water to dissolve the bulk of the excess sugar crystals. Next, use a butter knife to chip away at any remaining crystals, OR, add a bit more water to the jar (to cover the sugar crystals) and microwave it in 30 second increments until all the remaining sugar has melted and can be poured down the drain.
Can You Add TOO Much Sugar to Rock Candy?
Nope! Don’t worry about adding too much sugar to your sugar solution! If there is extra sugar in the liquid once the solution becomes fully saturated, it will simply settle at the bottom of the pot. Try to avoid pouring too much of the excess sugar into the jars, though, or you may end up with a very thick layer of rock candy crystals at the bottom of the jar!
What’s the Best Way to Store Rock Candy?
Store the rock candy in an air tight container for up to one year.
Can I use Powdered Sugar to make rock candy?
No, powdered sugar will not work well to create rock candy. Regular granulated white sugar works best for making homemade rock candy.
Homemade Rock Candy
What You’ll Need:
- 12 6-inch Wooden Skewers
- 12+ cups Granulated Sugar
- 4 cups Warm Water
- Food Coloring, if desired
- 1 dram Candy Flavoring, if desired
- 6 Quart-Sized Mason Jars
- 12 Clothespins
- Soak sticks briefly in water and roll in sugar to coat. Allow to dry completely.
- Add warm water to a large saucepan. Stir in 8 cups of sugar until no more will dissolve.
- Place the saucepan on the stove, and bring to a low boil over medium heat. Add remaining sugar and any additional sugar as needed until you reach a fully saturated solution and no more sugar will dissolve. If you’re using a candy thermometer, you’ll want the temperature to reach around 250 degrees F. Allow to cool for 20-30 minutes.
- Carefully pour the mixture into the mason jars and add food coloring and/or candy flavoring as desired.
- Add two sugared sticks to each jar, making sure that the sticks don't touch the jar or each other. Use clothespins to hold the sticks in place as needed.
- Place the jars in a warm and undisturbed location. Wait for 5-10 days until crystals are fully formed. Remove the sticks from the jar and enjoy.
Any additional questions? Leave them in the comments for us!
These rock candy sticks are a super fun STEM activity for kids of all ages, and everyone will enjoy the tasty treat that this fun science experiment creates!
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Don’t Forget to Pin This Rock Candy Recipe for Later!
Heidi Kundin, the vibrant force behind Happiness is Homemade, has captivated the hearts of millions with her colorful and inspiring approach to crafting, celebrations, and family fun. With 15 years of experience, Heidi’s website has become a must-visit destination for those seeking fresh and engaging ideas. Her warm personality shines through her posts, inviting readers to join her on a creative journey that’s not only fun but also achievable and budget-conscious. As a mother of three, Heidi expertly balances family life and her passion for creativity, proving that with a little imagination and dedication, happiness truly can be homemade!
My daughter wanted to make this for her business day at school. We’re pretty handy in the kitchen, so we thought it should work well. After pouring the syrup in the jars, they completely solidified. Is there any way to reuse the sugar and start over? Also, you don’t mention how much coloring to use or how much suggested extract. Can you please advise?
Hi Danielle, I’m sorry to hear that this didn’t work out for you as expected. You said that the syrup completely solidified in the jars…did that happen right away or after a few days? If it happened right away, you likely heated your sugar solution to too high of a temperature, which will result in the sugar reaching the hard-crack candy stage and solidifying into candy right away. Unfortunately, I haven’t had great luck with trying to rebatch the sugar solution, but I have heard of others who have been successful with it.
As far as the food coloring goes, that depends on the type of food coloring used (gel food coloring will require less than liquid since it’s more highly concentrated) and the color that you desire. As stated in the recipe card, if you want to add flavor extract, you will want to use the entire dram that it comes in. 🙂
I have been making A LOT of rock candy in the past 2 weeks. Some comes out beautifully and other jars end up having nothing but pooled sludgy sugar on the bottom of the jar after a few hours. I can’t figure out why the difference in results. Do you have any ideas?
Typically, the difference lies in three different things:
1) How saturated the sugar solution is.
2) The temperature that the mixture reached when boiling. (We recommend that the temperature get to around 265-270)
3) How well “seeded” the sticks were.
Rock candy can definitely be a bit finicky, so we always recommend using a fully saturated solution (you cannot add any more sugar to the mixture and have it dissolve), bringing the temperature up to 265-270, and make sure that the sticks you’re putting into the liquid have enough sugar on them initally for the new crystals to cling to and form upon. Hope that helps! 🙂
Angela Bean says
While my syrup mixture was cooling the heat from the pan kept cooking it and it completely solidified. I added water and heater it and it dissolved. How can I salvage the mixture?
Hi Angela, I’m sorry to hear that you were having trouble. When you added water and reheated it, how much additional water did you add? It is likely salvageable, but I need to know the amounts that I am working with here 🙂
Kirk Robertson says
What can I do with the remaining sugar syrup? My rock candy didn’t work out quite well but I have a bunch of syrup left.
I love rock candy
Nguyen Thien Tram Nhu says
I love it
We’ve never had very good luck attempting to make rock candy, but we FINALLY got it right with this recipe! My kids were so excited that they made their own candy! Thank you!!!
educational STEM lesson