Introduction: How to Make Rock Candy

Picture of How to Make Rock Candy

but not just any rock candy.... This is, boulder candy...

Step 1: Materials

Picture of Materials

Large Pot
Cotton String
Skewer Stick, spoon or something that covers the span of your jar

Step 2: Preparation

Picture of Preparation

Fill your jar with water leaving some empty space at the top. Pour this water into a pot.

Place the pot on the stove over medium heat. Heat until you start to see steam rise off the surface of the water. Now, slowly stir in sugar. Keep adding sugar until vigorous stirring does not dissolve additional sugar.

Next, pour the sugar syrup into a jar. Take care not to allow any sugar sediment to pour into the jar.

Step 3: Make Candy!

Picture of Make Candy!

Tie a long piece of cotton* string to a spoon, fork, skewer, etc. Then, measure the height of your jar and trim the string to this length. You may need to weigh your string down to keep it straight. For this, you can use anything that sinks in water - but avoid lead.

Place your jar in a place that it won't be disturbed for about a week.

After about a week, pull out your candy! If you don't see any growth within the first few days -- drain the sugar water into a pot, heat it and add more sugar. Also check that your string isn't super slippery.

If ants are a problem, place your jar on a plate of water - then add a few drops of detergent. This makes an ant moat.

Here at instructables HQ -- ants are a problem when it comes to leaving food on the counter.

*Do not use nylon or other synthetic stings as these are too slippery for candy crystal growth. Coarse cotton twine works best, providing locations for crystal growth to begin (these are called nucleation sites).

Step 4: Break Through

Picture of Break Through

My rock candy was left in the jar for too long... So, to salvage - I had to break my jar for the full effect. Wear safety glasses ;)

Step 5: How It Works

Picture of How It Works

By heating and agitating water while adding sugar, a saturated liquid is formed. As the syrup cools and evaporates, the fluid becomes super saturated - meaning the water has more sugar than it can hold. When this happens, sugar looks for a place to escape - these places are called nucleation sites and sometimes called "seeds."

The string provides the nucleation sites for crystal growth. As the water evaporates, more sugar crystallizes on the string - growing the rock candy.


shatteredbreeze (author)2015-07-05

made it! one with vanilla, one with brown sugar, and two each of orange and strawberry flavor. gonna see how they turn out in a week or so. i used hemp string for a rustic look. hopefully it'll turn out with some nice crystals.

Did you take any pics?

The cloud 1808 (author)2016-03-28

? =}

luh_bri (author)2015-11-18


Wlngfrvr (author)2015-10-21

I love cj rey mwaa

Wlngfrvr (author)2015-10-21

I love cj rey mwaa

Wlngfrvr (author)2015-10-21

I love cj rey mwaa

Wlngfrvr (author)2015-10-21

I love you cj reyy mwaaaa ?

Wlngfrvr (author)2015-10-21

Ncba students.
I cj rey mwa mwaàa

funny70 (author)2015-01-07

Can u use mio for flavoring??

Max-anB (author)funny702015-05-23

Yes also Walmart has several flavors for under $3 a piece for 2 oz and u really only need a small amount to flavor ur candy.

RoseW2 (author)2015-03-10

I don't know why, but my sugar keeps coming off my stick?? I have tried many different solutions but it will not stay. Can you help me?

Max-anB (author)RoseW22015-05-23

If u r using string or wood I recommend dipping it in water then dip it in sugar lightly coating ur surface for growing the rock candy. It will give the candy something to grow on. :) good luck next time.

NeonJuggalo (author)2014-12-02

rock candy, damn auto correct

JenniferS2 (author)2014-11-15

Can you flavor/make it with kool-aid?

sector47 (author)2008-05-16

who wants candy!!!

esparanzak (author)sector472014-09-17

Count me in!!!

Shany120 (author)sector472011-03-08

I do!!

mason0190 (author)sector472008-08-10

I DO!!! :D

Huntman00 (author)2010-03-05

Can u wash out that pot easily... my mom mite get pissed if i do this... please reply soon

Jimmy Proton (author)Huntman002010-07-31

as long as the sugar doesn't caramelize then it will come off with water

SKelem (author)Jimmy Proton2013-10-03

If it does caramelize, you can fill the pot with hot water, and the caramel will dissolve.

csk14 (author)2010-06-02

Can you color the candy?  Maybe put food coloring in the water or ad a fruit.

Goygar (author)csk142011-11-14

Adding food coloring or fruit gives no real problems. But to flavor the candy, it is best to add a candy flavoring or an extract of some flavor.

jeanphyl (author)2011-03-16

Wow this is new.Did u actually eat it?

Jimmy Proton (author)2010-08-18

ive had mine out for over 2 weeks and nothing has happened

DrWeird117 (author)2009-08-15

Smoke it.

Huntman00 (author)DrWeird1172010-03-05

you can do that... then comment in a week and we will see if u lived

crazygurl (author)2010-01-13

i love sean!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

crazygurl (author)2010-01-13

is it eatable?????????????

crazygurl (author)2010-01-13

tis is the fucken bomb

mae-kitty (author)2009-11-14

 KoZuEst, the pantyhose was a great idea. I tried to and it kept everything out. =D and also, if your having trouble growing the seed and or the crystal, either go out and buy rock candy then use that as the seed, or you can do what i did. Use a sugar cube. It works great lol.

EncasedDeath (author)2009-10-06

if i put it in a cold area will it harden quicker and not have to wait a week?

link605 (author)2009-10-03

to the author you should add a washer to the bottom of the string to keep it straight so if you make more candy you will still have a jar : - )

namraps (author)2009-09-19

Maybe I'm missing it, but I saw nothing about the amount of sugar.

trebuchet03 (author)namraps2009-09-20

Step 2

Keep adding sugar until vigorous stirring does not dissolve additional sugar.

chi chi chippy (author)2009-09-18

can u make it on a skewer like you see if u buy rock candy from a store?

circlethewagons (author)2009-09-16

I followed the instructions and filled the bottle close to the top like you said, and ended up with way too much sugar water. Considering that you have to mix in twice the amount of sugar as water in order to reach the saturation point, you end up with about one and a half times as much liquid. Next time I'm only going to fill the jar a little more than half way. Another tip is to wet the string with water, then coat it with sugar, and let dry. This will attract additional crystal formation. Also, use a paper clip tied to the end of the string and keep it from touching the bottom or sides of the jar.

Jent13 (author)2009-09-12

To get bigger rock candy crystals after you have made the sugar syrup dip the string in it then roll it around in some sugar. Let dry. the put it in the jar. I did that and i got bigger sugar crystals because they had something to grow on and it keeps them from growing on the bottom and sides as much because it has a better texture.

dchall8 (author)2007-07-20

My daughter likes to buy rock candy sticks. The ones she gets have clear (no color), red, green, blue, and yellow crystals - sort of like a rainbow from top to bottom. I wonder how they do that?

noname420 (author)dchall82009-09-12

ok on my next batch of rock candy i have an idea, my idea is to put a little sugar water is put half in color it, color the other half while still in the pot than carfull put it ontop so see if one will stay ontop of the other, if they do they might do it with 5 colors

colinludwick (author)2009-06-25


KoZuEst (author)2009-05-21

A better alternative for the string would be a wooden stick. Probably something like those bamboo BBQ skewers, although bamboo might also be a bit too "slippery". I just think using a stick instead of a string makes the candy better to eat.. like a lollipop. Chewing on a piece of string is somewhat unpleasant. Also, maybe something to protect from the dust? If it needs to sit there for a week.. there will probably be some dust or dog hair in it. I don't like hair in my candy.

trebuchet03 (author)KoZuEst2009-05-21

You can dust cover as long as it allows the solution to evaporate, that is, no airtight covers (probably not plastic either) ;)

KoZuEst (author)trebuchet032009-05-21

Pantyhose.. :D I know, they put jars of water covered with pantyhose in pianos to keep the humidity levels stabile.

natethegreat88 (author)2009-05-08

Ummm... I think I should make some Root Beer rock candy! *drools*

mynameishamm (author)2009-05-03

brazilian sugar works?

dinosoarzsayrawr (author)2009-04-26

its sweet literally! :D I need 2 make some! actually my friends made rock candy for science class, they wanted to make flavored rock candy and used kool aid instead of sugar. I guess because it was so sugary because of the kool aid it grew bigger faster! I wonder about ice tea rock candy?

seasonticket1256 (author)2009-04-11

yummy candy

d2j5 (author)2009-04-03

nice! finaly i know how to make rock candy. i have been looking all over for ideas

About This Instructable




Bio: Engineer making renewable energy products for African entrepreneurs.
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