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Homemade Rock Candy: Tips, Tricks and FAQs

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Make homemade rock candy with these tips and tricks and answers to frequently asked questions. A fun science experiment and treat for kids!
Make homemade rock candy with these tips and tricks and answers to frequently asked questions. A fun science experiment and treat for kids! 

With summer here and knowing that moms are looking for fun activities for kids, I decided to share how we make rock candy!  This is an oldie but goodie post here on Gluesticks.

Homemade Rock Candy is easy to make, it just takes patience. There are so many variations using string, sticks, etc. It’s a beautiful science project and sweet treat all in one. It does take time, and the end results can vary. We found that some colors grew really well and others didn’t grow as much. There’s a science to it and that’s all part of the fun! Scroll to the bottom for some frequently asked questions for making rock candy.

My son has a batch growing on our window sill right now as a little project for Cub Scouts. He used a string and didn’t color his sugar water, but the result is the same as the rock candy we made before. For us, it is more fun to watch the crystals grow than to actually eat it.

To make homemade rock candy on a stick, watch this video tutorial or scroll down for written directions! I’ve also included more tips and frequently asked questions at the end of the post.

Ingredients:

  • Sugar (lots of sugar)
  • Water
  • Food Coloring (concentrated for brighter colors)
  • Wooden Candy Sticks or Bamboo Skewers
  • Funnel
  • Glass Jars
  • Clothespins
    flavoring (optional)

Instructions:

1. Trim down your skewers to a reasonable size to fit in whatever jars or cups that you will be using. You’ll also want to get rid of the point. Dip them in water, then roll in sugar.
2. Let the sticks dry completely and set aside. This will give the sugar a base (something to stick to when it starts to crystallize).
3. Mix equal parts of water and sugar in a pot on med-high heat until dissolved. Then continue to add sugar until you have 2:1 – 3:1 ratio. It will get to a point where it won’t dissolve any more.

Note: We used 18-20 cups of sugar and 8 cups of water and it made a lot. So you can definitely half the recipe or create as little as you like as long as you keep the same sugar/water ratio. You are making a nice, sticky, sugary syrup. Mix until mixture starts to simmer.  You do not need it to a rolling boil or bring it to a certain temperature with a candy thermometer. Easy.

4. Allow your syrup to cool for a few minutes and ladle into your jars using a funnel to catch spills. It is still very hot at this point.
5. Add food coloring and flavoring if you’d like.
Note: We used the tips that we trimmed off of our skewers and dipped them into concentrated food coloring paste, then swirled the skewer into our hot syrup mixture. You can use liquid food coloring, but I like the paste better. We did not flavor our homemade rock candy.
6. Attach a clothespin to each skewer (the ones you dipped in sugar and let dry) and place in the cup.
Note: Make sure the skewer isn’t touching the bottom or sides of jar/glass. They need room to grow. Since our glasses were narrow, one skewer seemed to work out best, but we added two in a few of the colors.
Make homemade rock candy with these tips and tricks and answers to frequently asked questions. A fun science experiment and treat for kids! 

It only takes 7 days to make homemade rock candy and it’s so much fun to watch and see the changes each day!

7. Place your jars in a warm location with lots of natural light and watch the crystals grow!
Note: the photo above is on day 1. You can see that there is a bit of sugar build up from when we dipped them in water and then let them dry in sugar as well as on the bottom of the glass. I had no fear of insects or little fingers messing with them so I did not cover mine. I do not know if covering them would alter the process at all.
Make homemade rock candy with these tips and tricks and answers to frequently asked questions. A fun science experiment and treat for kids! 
 Day 3. More crystallization.
Make homemade rock candy with these tips and tricks and answers to frequently asked questions. A fun science experiment and treat for kids! 
 Day 5. The syrup is crystallizing on the bottom of the glasses as well.
Make homemade rock candy with these tips and tricks and answers to frequently asked questions. A fun science experiment and treat for kids! 
Day 7. DONE! We had a great time watching them grow and sampling the finished product.

Frequently Asked Questions:

Can you make more than one stick of rock candy in each jar?

If you attempt to do more than one skewer/jar, use a wide mouth jar. The orange glass had two skewers and both turned out GREAT, but a couple of the other glasses with 2 were a bit smaller than the rest of the single stick glasses.

How do you drain the rock candy?

Hold the lollipop over the jar or paper towels to let most of it drip off and then set it on a cookie sheet to dry.
There will be crystallized sugar in the bottom of your jars/glasses. Just run them in hot water and chip it out with a butter knife. It comes out pretty easily.

Do different colors grow faster than others?

And as you can see in the photo, they didn’t all grow at the same rate. The purple one was the biggest we had. So there are obviously many variables to doing this which makes it such a great science experiment.

How long will rock candy last?

The shelf life for rock candy, if kept in a dry location, is 1 year.

Can I use a disposable foam cup for making rock candy?

Nope. It has to be glass, and it’s easier to watch the crystals grow in a clear glass jar!

Why didn’t my rock candy grow crystals?

If after a couple of days you don’t see any sugar settling on the bottom of the glass, it means that there most likely wasn’t enough sugar when you started. Just reheat your syrup to a simmer and add a bit more. Pull your skewers out and just roll the sticky skewers in more sugar and let it sit while you reheat your syrup. Is this frustrating to do? Yep. I know, because I’ve done it before!

Can you re-use rock candy syrup to make more crystals?

This is probably the most asked question that readers have e-mailed me over the years. I have not tried to re-use the syrup, but I don’t see why you couldn’t add another stick (covered in dry sugar) into it and grow another more. It might be worth reheating it to test and make sure that it is still saturated, but you have nothing to lose except a bit of time.

Here’s are a few more tips for making homemade rock candy:

  1. Make sure your glass/jars are clear and CLEAN.
  2. Make sure your sugar ratio is AT LEAST 2:1-3:1 When I said it will get to a point where it will not dissolve anymore, that does not mean that it will be gritty and super thick. It will still look like a clear syrup, but a little cloudy. That is when you will know that it is a saturated ratio. Just make sure you bought extra sugar so that if you get to a 2:1 or 3:1 ratio and it is still dissolving super quickly that you can add a little more.
  3. Place in a WARM, SUNNY location. I made this last batch in September when it was still 80+ degrees. I’m not sure if the time of year has anything to do with it or not.
If you liked this homemade rock candy recipe here are more fun and easy science experiments for kids!

science experiments

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Comments

  1. What a neat idea. I vaguely remember making sugar crystals on string like this in science class back in the day… skewers are way better for eating it though!

    Reply

  9. Hi, I just came from Tutorial Tuesday. This is such a great tutorial. My mom would love making this with my sons.

    I’m now following you. Please stop by when you have a chance and join us. We have fun crafts and some are eco-friendly.

    Reply

  17. I remember doing this with my brothers when we were in middle school. We never thought of coloring it! I should make these with the kids. You know my girl is the sugar addict. 🙂

    Reply

  28. This is great! I’ve looked into buying these for a party and I think making them would be much cheaper and the plus is that this would be a great science lesson for my son – delicious and educational; the best of both worlds…LOL! Thanks for this post! (coming to you from Nifty-Thrifty linky party)

    Reply

  35. @Rebecca, I’m not sure, but I don’t see why not! As long as it is still a thick sugary syrup mixture again when it’s heated up again I would think it would work!

    @Damienne, yes you can! I just didn’t have any!

    Have a great week ladies!

    Brandy
    Gluesticks

    Reply

  39. Thank you so very much for the reminder! I think the last time I made these was over 10 years ago. We didn’t dip the skewers in sugar first so there was some coverage issues. We did make them in clear plastic containers so we could easy break any lingering crystals out and then reheated them and the syrup to make more rock candy. Once again thank you for the reminder! I know what we are going to be making for the cousins for christmas!!

    Reply

  40. Does anyone know if you *have* to use the wooden skewers? I have some of the paper-ish lollipop sticks on hand and wonder if those would work?

    Reply

  42. Mama B- I’m not sure. I’ve just always seend them int he stores with wooden skewers. Good luck!

    Mama-tbull- Oh no! I’m not sure what went wrong. As long as they are in a warm sunny location and there is at least a 2 to 1 sugar/water ratio, I’m not sure what else could have gone wrong. Was there a good coating of sugar on the skewers so that the crystals had something to grow on?I wish I could help more. Give it a few more days before throwing in the towel.

    Reply

  46. Hi Wendi!

    I honestly have no idea. Sorry that I am not much help. Maybe you can find another recipe online that does this. I know that honey crystalizes in the container after awhile. But I really haven’t thought too much about it.

    Have a great week!

    Brandy

    Reply

  49. Ok, I’m trying this… unsuccessfully. So did you wait until your solution was cool before you put your skewers in? The sugar dried onto my skewers is just dissolving into my solution. 🙁 How long did you “dry” your skewers with sugar on them?

    Reply

  50. Stevie, I only let the sugar cool 10-15 minutes or so before adding the sticks. Some of the sugar will dissolve off of the sticks, but it should still give it enough of a base. How long has it been since you dipped them? Was it today? Or a couple of days ago. If it was today, I’d give it 24 hours and see what happens tomorrow. I think you’ll be surprised and see some progress. Let me know!

    Reply

  51. Oh, and as far as how long I dried my skewers that had been dipped in sugar. Just long enough so that they are DRY. Not moist at all. I dipped them first, then created the syrup mixture, then waited the 10 mintues or so for the mixture to cool before putting them in the syrup. By that time they were dry. Good luck!

    Reply

  55. Hi Cecelia,

    I’m not sure why you couldn’t re-use it. It’s pretty much a simple syrup, but I have not tried to do so and am not sure how long it would stay good for.

    Brandy

    Reply

  57. I am also having problems getting anywhere. My syrup is between a 2:1 and a 3:1 (Sugar:water)

    I used wooden skewers and mason jars. I let the dipped sticks dry by a fan for an hour… Do you think the syrup might have been to cool when I set the skewers? It’s day three and all the sugar as dissolved and no crystals on the sticks or the bottom. I am willing to try and tips you may have 😉

    Reply

  58. Borders Family,

    I sounds like you did it right. I don’t think it was too cool. It should have been fine, but I’ve had to warm up my sugar again before and add more sugar to help jump start the process even when the previous time I made it, it worked out fine with the same sugar/water ratio. So I don’t know what mades it sometimes work and another time need more sugar. Just reheat your syrup and add more sugar (the same method you did before….stirring until dissolving and can’t disolve anymore) and keep it in a sunny location.

    Just pull your skewers out and roll them in sugar while you reheat your syrup. They should be ok to stick back in as long as they are thick and dry.

    I am so sorry that it hasn’t worked out for you yet, but it will!

    Reply

  60. Hi Bernadette, I haven’t tried covering mine before so I’m not sure. Sorry! But I understand what you mean. The summer is the perfect time to do rock candy in a warm window, but is also the perfect time for bugs…

    Reply

  62. Hello there, thanks for the post. Our family is doing this for our summer bucket list!

    Just an observation: folks don’t hold yourself to any particular timeline. We didn’t start to see crystals forming until about day 7. Here we are at day 14 and we pulled one out and it is similar to the smaller one pictured. We have decided to wait another week to see what more we can get.

    I knew we had something within the first three days though, because crystals started forming in the top water line and at the bottom of the glass. If you don’t have these crystals within the first 4-5 days, you probably need more sugar.

    I covered the tops loosely with cupcake liners. I just slipped them over the top through a small hole in the bottom. I too was worried about critters. It also stopped prying eyes from trying to touch.

    Reply

  67. I have a question! I would like to make these for my daughter’s winter wonderland birthday party, but I’m worried it might be too cold now. We have only north-facing windows in our apartment with no direct sunlight. Would there be enough light that way, or would it be too cold for the crystals to grow in our window sill? We’re in MN and temps have been between 20-40 most days.

    Reply

  71. I made these, they seem to have turned out fine- except for the fact they are completely stuck to the bottom on the jars! I atacked a couple with a knife and ate a small peice. Is there any way to get the lumps out without melting the whole lot?

    Reply

  72. Oh no! The sticks may have been a bit too close to the bottom of the jar, but it sounds like they grew a decent size for you! I’m not sure how to break them out without breaking the candy. Ours didn’t hit the bottom. Crystals grew along the bottom, but they weren’t attached to the wooden stick. I’m so sorry!

    Reply

    • It’s not too terrible, two candies came out perfectly, another one fell apart and the last 2 are stuck. I’ll try holding them over steaming water and hoping they come out all right. The broken pieces I managed to chip out are so pretty and sparkly, I love looking at them in the light before eating them haha

      Reply

    • Hmm…I’m not sure. If after another day or two you don’t see any growth, you might try pouring it back in a pan, add a bit if of water to dilute it and reheat it to make the syrup again. I’d just hate to see it go to waste! I would still wait at least a day though.

      Reply

  74. What an awesome experiment/recipe to try with my kids! I’m curious… Has anyone tried flavoring their syrup with any sort of extracts? I would love to try it, just not sure how much to use. I guess that’s why it’s an “experiment”! 🙂

    Reply

  76. I love this activity. I have 3 daughters and we made this one of the nights events during a 12 girl sleep over. I used the smaller mason jars and labeled each jar with the girls names. I did a test 2 weeks before and found that you really need to have a very good sugar base started on each stick to get the best results. We used the solid food coloring and hard candy flavoring. To help with keeping the bugs away I used some of those outdoor pop up nets you use for outdoor dinners over your plates. The girls loved that they got to see a progress report every evening on their Instagrams. Day seven they were all over after school to collect their rock candy. Thank you

    Reply

  80. Just a thought, it seems like the darker colors did better. Maybe attracted more sunlight. Yellow and pink seem to be smallest and are also the most translucent.

    Reply

  82. oh my goodness. It’s like you were reading my mind! I came to your blog today, specifically looking for this exact post! I’m totally weirded out.

    Reply

  85. If you are having problems making the rock candy, here is a tip that might help.

    Unlike the article says, warm, humid areas do not help the crystals form at all! Heat evaporates the water, yes, driving the sugar to crash out of the solution (LeChatelier’s principle). This cannot happen in humid environments. The sugar solution in a warm environment won’t always come out stuck to the stick like you want it to though. In order to make the sugar crash out into the nice cubic pattern stuck to the stick, you want to get the stick in the syrup solution while it is still warm/hot, then immediately store in a cool, dry place. A warm place will cause the sugar to not want to join the crystalline structure on the stick and might not even cause any sugar to come out of solution (warm liquids can hold more solute).

    Background: Master’s degree in Organic Chemistry, where crashing compounds out of solutions is common practice.

    Reply

  88. We put our skewers through unbleached coffee filters to keep the dust and pet hair out of our jars but allow for evaporation. It seemed to work well. Also, when we made this during a high humidity period it was a complete failure (but still fun.)

    Reply

  89. Just curious but….my daughter and I are using this as her science project and after one day the glasses looked a little odd. We did three glasses and the surface all have the crystals on top but none on the actual candy sticks. Is that normal? Are we doing this right? We made sure to saturate and roll them in sugar but the sugar base has come off in the water. Please help!

    Reply

    • Ours did that too! I don’t think we noticed crystals until growing until day 3 or so. By day 7 we almost had to chip the top layer a bit to pull the sticks out. We’ve made this and had it fail too. If by day 3 (4 at the latest) you don’t see any growth, go ahead and heat the syrup up and try again. The fact that your syrup is hardening a bit is a good sign that you used enough sugar. I know you can make it with string too instead of wooden skewers. I’m not sure about the lollipop sticks. Good luck! 🙂

      Reply

  90. After going back and rereading through the process and materials, I wonder if we shouldn’t have used the sticks we did. It looks like you guys used wood instead of the candy sticks (like the type you would use for cake pops). I wonder if that makes any difference. Maybe if we don’t see any growth after three days we will start over using kabob skewers in hopes it will work better.

    Reply

  91. I remember doing this in science class when i was a kid and the ratio was 500 ml of water to 5 lbs of sugar.. This is crazy that i remember this cause im 48 yrs old.. wow how the mind works..LOL

    Reply

    • Haha, we remember what is important, right? I never made it as a kid, but had a great time making it as an adult…I just didn’t care to eat it. It was fun to watch grow 🙂

      Reply

    • Hi Donna, we used 8 glass cups and were able to get 10 rock candy sticks from those. If you have wide jars you can get two from each jar, but ours were skinny glass cups and the ones that made two were really small. I would stick with 1 stick per glass or small jar.

      Reply

  94. Well I have to ask because i haven’t seen anything about it. What to do when they come out if the jar? They are dripping syrup! I don’t want my daughter eating them like that as it causes too much of a mess. Should I pat with paper towels? The syrup is so thick I don’t know that paper towels with soak it up.

    Reply

    • Hi Cynthia! I held the lollipop over the jar to let most of it drip off and then set it on a cookie sheet to dry. You can also leave the clothespin on and just transfer it to an empty jar to let the excess drip off and let the lollipop dry. I will add this to the post in case anyone else is wondering too!

      Reply

    • Hi austin! I would just recommend taking your sticks out, rolling them in sugar and adding them back. Hopefully the sugar will give the syrup something to stick to. The fact that the crystals are growing on the glass means that your syrup is at a good saturation and so the only other thing I can think of is the sticks. Good luck!

      Reply

  96. How awesome! Ive always wanted to make these on a stick! I have a question that may have already been asked! Sorry! Once one stick is done growing, is the jar of syrup still good to make another one?

    Reply

    • Hi Heather! After 5-7 days, there are crystals growing on the bottom of the glass too. I also found this online that said “Rock candy is formed because the solution is “supersaturated” with sugar. Once it forms, the syrup is not supersaturated anymore and will not make more rock candy unless more sugar is again dissolved in it.” Hope that helps!

      Reply

    • Hi Emma! I haven’t tried reusing the solution before because mine usually grow solid crystals on the bottom and sides of the glass as well, but from what I have read from other sites you can reuse the solution if it has been reheated. If it has a slight cloudy look the sugar is still saturated in the syrup. If it looks completely clear, add a little more sugar. Good luck!

      Reply

    • Hi Jamie! I honestly don’t know. I’m sorry I couldn’t be of more help! I’m not sure how they compare to sugar. I know you can substitute when baking, but am not sure for things like this.

      Reply

  100. I want to make the solution and provide the pegs and sticks as party favours…will it be fine if sticks are dipped into solution a day or two later?

    Reply

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