Homemade Rock Candy

Homemade Rock Candy gluesticksblog.com

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 (originally posted in 2011).

Homemade Rock Candy is incredibly easy to make, it just takes patience. There are so many variations using string, sticks, etc. We’ve taken bits and pieces of what we found online (and our own trial and error) and here is how we successfully made rock candy at home. My son has some growing in 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. It’s a beautiful science project and treat all in one.  To make rock candy on a stick, follow the directions below!

 You will need:
Sugar (lots of sugar)
Food Coloring (concentrated for brighter colors)
Wooden Candy Sticks or Bamboo Skewers
Glass Jars
flavoring (optional)
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. Let dry completely and set aside. This gives the sugar a base. Something to stick to when it starts to crystallize.
Homemade Rock Candy gluesticksblog.com

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 anymore.

The first time I attempted homemade rock candy I used a 2:1 ratio and after 3 days of ZERO growth, I poured it all back and heated each individual glass of syrup over the stove again and added more sugar. I wouldn’t recommend doing that, it was a pain, but I didn’t want it to go to waste! I added a bit more sugar to it and it worked. So that’s why I would suggest definitely a 2:1 ratio and then adding a little sugar at a time until it starts to look a little cloudy. That is the point that it has reached saturation.

We used 8 cups of water and 18-20 cups of sugar and it made a lot. So you can definitely half the recipe or create as little as you like as long as you keep within 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.

Homemade Rock Candy gluesticksblog.com

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. 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. If you’d like to add flavoring, now would be the time to do it. Just a few drops in each glass. We did not flavor ours.
Homemade Rock Candy gluesticksblog.com

Then attach a clothespin to each skewer (the ones you dipped in sugar and let dry) and place in cup. 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.
Homemade Rock Candy gluesticksblog.com

Place your jars in a warm location with lots of natural light.  Here they are on day one…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.
Homemade Rock Candy gluesticksblog.com

 Day 3. More crystallization.
Homemade Rock Candy gluesticksblog.com

 Day 5. The syrup is crystallizing on the bottom of the glasses as well.
Homemade Rock Candy gluesticksblog.com

7 days—DONE! We had a great time watching them grow and sampling the finished product.
In the end, the glasses with 1 skewer did better as they had more room to grow.
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 skewered glasses.
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.
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.
*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.
It’s been almost two years since I originally posted this method/recipe and I’ve received many positive emails, but a couple of ones that were failures from readers. So I thought I would post a troubleshooting section with tips that I have for success as well as some that I found when I “Googled” it. I know how frustrating it can be when it doesn’t work out (It’s happened to me too) and I always hear, “I tried making that as a child, but it never worked), so there must be a large variance in things that affect the outcome. So here goes…
My tips:
Make sure your glass/jars are clear and CLEAN.
Make sure your sugar ratio is AT LEAST 2:1-3:1 You may need more depending on how quickly it reaches saturation…
 “Mix equal parts of water and sugar in a pot on med-high heat until dissolved. Then continue to add sugar until you have AT LEAST a 2:1 ratio. You can also do a 3:1 ratio. It will get to a point where it won’t dissolve anymore……”
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.
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 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!
I have not tried the following, but I thought if what I’ve shared that worked for me hasn’t worked for you, that maybe something here will help.
No crystal growth
This is usually caused by using a solution that isn’t saturated. The cure is to dissolve more solute into the liquid. Stirring and applying heat can help to get solute into solution. Keep adding solute until you start to see some accumulate at the bottom of your container. Let it settle out of solution, then pour or siphon the solution off, being careful not to pick up undissolved solute. If you don’t have any more solute to use, you can take some comfort in knowing that the solution will become more concentrated over time, as evaporation removes some of the solvent. You can speed this process by increasing the temperature where your crystals are growing or by increasing air circulation. Remember, your solution should be loosely covered with a cloth or paper to prevent contamination, not sealed.
If you are sure your solution is saturated, try to eliminate these other common reasons for lack of crystal growth:

Too much vibration Keep your crystal setup in a quiet, undisturbed location.
    • Contaminant in the solution The fix is to re-make your solution. The fix only works if you can avoid contamination (won’t work if your starting solute is the problem). Common contaminants include oxides from paper clips or pipe cleaners (if you’re using them), detergent residue on the container, dust or something else falling into the container.
    • Inappropriate temperature Experiment with temperature. You may need to increase the temperature around your crystals to get them to grow (increases evaporation). For some crystals, you may need to decrease the temperature (which slows the molecules down and gives them a change to bind together).

science experiments

Here are more fun and easy science experiments for kids!

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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!

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.

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. 🙂

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)

@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!


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!!

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.

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!


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?

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!

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!

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.


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 😉

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!

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…

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.

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.

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?

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!

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

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.

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”! 🙂

So many people have mentioned flavoring it, but haven’t reported back to say if they’ve tried it or not! I don’t see why it wouldn’t work! Maybe try different amounts in each glass! Have a great week!

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

Wonderful! Thank you so much for sharing your experience with making rock candy! And THANK YOU for giving us the right ratio for flavorings. I’ve had several readers ask about flavoring the candy, but I’ve only made it with straight sugar for my kids.

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.

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.

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.

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.)

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!

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! 🙂

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.

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

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 🙂

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.

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.

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!

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!

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?

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!

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!

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.