Introduction: Make Hot Ice - the Complete Guide

The complete guide to making hot ice and sodium acetate. How to create it, fix it, and use it. All methods from baking soda and vinegar to laboratory synthesis are shown.

The basis for hot ice is sodium acetate trihydrate, which is heated above its melting point and then cooled below its melting point so it's supercooled. It's still liquid and quickly solidifies when a seed crystal is introduced.

Sodium acetate trihydrate can be bought, or made at home by mixing three tablespoons of baking soda with one liter of vinegar and boiling down.

The video shows a detailed step by step instruction on how to do this as well as how to fix problems you might have.


jai lok (author)2015-11-09

but its not working..

hey jack (author)2014-11-08

Wat is a seed crystal

JillianM3 (author)hey jack2015-09-13

Crystals, such as ice, cannot form without either a disturbance in the liquid causing the crystallization bonds to form, or another crystal already formed for the liquid to build off of.

ST⭐RS (author)2014-01-21


nannysaunders01 (author)2013-08-18

hi sorry to ask again but I wanted to make this to demonstrate to my sisters primary school kids, and not working very well. I keep reading other instructable pages and they all do it totally different. for example:
You use 1litre vinegar to 3tbls bicarb soda. i have converted but Indigoandblack uses 1 gallon (3.7l) vinegar to 12 oz ( 20 tbls ) bicarb soda.
Why does he use so much more bicarb soda? and is this why with me using 3 tbls my hot ice is not solidifying but going mushy? i also read in other sites that you don't have to worry about measurements, more so add until supersaturated, so keep adding the bicarb soda until the bubbling reaction stops. thanks

nannysaunders01 (author)2013-08-18

ok, really confused now, as mine not working so trying to work out why it is going mushy and not freezing solidly. i just read the instructable by c.stokenbury -
Why does he do your steps, filter it, dry it to get left with the crystals then take the sodium acetate crystals and dissolve them in boiling distilled water?
I get it if he started with concentrate acetic acid, but if he started with vinegar that already has water in it, why is he doing an extra step with water?

nannysaunders01 (author)2013-08-18

ok, first one i put in a water bath of 1C. it turned to mush. i thought it turned to mush because the temp of bath was too cold, didn't even have time to take temp of sodium acetate. I saw you said add more vinegar, so I did. supercooled it down to 16C and it just wouldn't crystalise. I notice that my vinegar is cloudy and has sedimentation which it says on label is normal. would this be contaminating it. where else can i get vinegar apart from supermarket, is there a better one? To start with my liquid boiled down so only about 5 % was left before the film started. What am I doing wrong? I can see loads of flecks and bits in my solution, I am thinking the vinegar has particles in it. Would using the charcoal help with this?

oldmanbeefjerky (author)2011-06-18

heres a clever idea to reduce the chances of burning the acetate, when you are boiling it to remove water,

freeze your vinagar, almost before use,

vinegar i beleive has a high melting tempurature, and will form crystals well before the water freezes.
simply put into the freezer until the tempurature drops below 16 degrees celcius, then scoop out the crystals , but include a small amount of water.

this will be about 70-90% vinegar, and will yeild just as much sodium acetate, but will require less boiling, and shorten the time you risk burning the vinagar.

This sounds like a great idea. I wonder what NurdRage thinks of it. He demonstrated a few methods, but not this one. It seems to me that freezing the (clear) vinegar should work, but I'm an amateur.

webmanoffesto (author)2013-06-22

Thank you for the outstanding video. I can see you put a lot of time into it. I've been struggling with this one and haven't succeeded yet. Mainly because I've been hacking at it and not following the instructions closely. Thank you for saying "this is a tricky one". I find it frustrating when on YouTube it looks easy but in reality it's complicated. If it's complicated then the speaker should say so. If I still choose to try, then at least I know it's a tricky one.

AtmaIII (author)2011-10-27

There is extra info in here about the specific composition of the heat packs and recharging (though that is not the primary topic of the paper)

dsherlock (author)2011-09-22

Awesome video: able to do it first time:mine was a gentle amber colour.

divad135 (author)2011-08-16

I did this and it worked the first time :) Thank you. But it ended up being the white color of the high quality hot ice , not brown as shown in the video.

carlinc (author)2011-01-05

I have preformed this several times, and I must say, this video is excellent!! The walk through is clear and in great detail. Thank you for a great instructable!

Berkin (author)2009-10-19

Can I distill household vinegar to get rid of the impurities?

NurdRage (author)Berkin2009-10-19

Instead, just make the hot ice but when you boil it as you get close to the crusting stage turn down the heat and boil it very gently. The less burning the less browning you'll get.

you can still distill the vinegar if you want, but i think its too much of a hassle compared to just gently boiling it.


Berkin (author)NurdRage2009-10-19

Alright, thanks for the advice.

renaud4 (author)2010-12-07

i never get to the crusty film part of the boiling and i am too lazy to let it evaporate in the air. what am i doing wrong?
i divided the ingredients by 3 so its 1/3 liter 5% Vinegar(Distilled white) and 1 tbsp of baking soda and added baking soda untill it dtopped reacting, and made sure it was clear. thne i started to boil and waited an hour to see the film, but i get nothing. i need great help because this is a very simple chemical to create, and i can make copper carbonate, nickel carbonate, copper acetate, nickel acetate, copper sulphate, and some solution with polyacrylamide

NurdRage (author)renaud42010-12-07

Why did you keep adding baking soda?

I never say to keep adding until it stops reacting.

hey NURD(YOU DIDN'T ANSWER ME PRIVATE MESSAGE!!!). If i buy 95% acetic acid and sodium bicarbonate, will it be clear(white)?

renaud4 (author)NurdRage2010-12-07

I only got it to work once, and if i get extra sodium bicarbonate, can i filter it in coffe filters?
i found this solution great for filtering copper acetate used to make copper carbonate by freezing the liquid from the copper carbonate and filtering the sodium bicarbonate out of the bottmom of the test tube

NurdRage (author)renaud42010-12-07

extra sodium bicarbonate will dissolve in anyway and won't filter out, the only way to fix it is to add more vinegar to compensate.

renaud4 (author)NurdRage2010-12-07

ok makes sense, so that is the solution to my problem?

redlizard5 (author)2010-07-20

can u use distiled white viniger

hellonfire30 (author)2010-07-06

do we actually need 1 liter of vinegar. can we use like 1/3 of a liter and 1 tablespoon of baking soda

bunnieboo43 (author)2010-04-20

This is an excellent walk-through! I will be using this in my classroom!

woahwoah2 (author)2010-04-18

if you put your finger in long and it starts freezing would your finger be stuck?

scar94 (author)2010-01-25

did it stink while you boiled it?

Near24 (author)scar942010-03-03

 ya, a lot!

scar94 (author)2010-01-27

why isn't mine forming crystals on the sides of the pot

vikings84 (author)2009-11-14

I don't know why, but at school when ever lunch comes around my hands are freezing! even in the summer.. so i looked into this experiment to make me some homemade hand warmers because it is really annoying when my hands are constantly cold. any suggestions for containers that i could put the acetate in and reboil it so i can reuse it??

AmyLuthien (author)2009-11-13

So what happens if you use a copper pot?  Besides having a very shiny pot?

NurdRage (author)AmyLuthien2009-11-13

Dissolves the pot

AmyLuthien (author)NurdRage2009-11-13

Whoops!  Guess that makes sense - since you'd be boiling it  for so long.

Did I also hear correctly?  You can mix the solution and then set it out to evaporate, and it will for crystals?


Berkin (author)2009-10-20

I made a [ video] of my sodium acetate crystallizing. I got the recipe right on my first try!

Berkin (author)2009-10-20

I just made some sodium acetate and accidentally froze my finger in it! I had to break up the hot ice with a knife to get it out. XD

NurdRage (author)Berkin2009-10-20

It's pretty soft, unless you prechilled it far below zero it should be mushy enough for you to pull your finger out.

Next time try that before running the risk of cutting yourself with the knife.

Berkin (author)NurdRage2009-10-20

The solution was actually warm, but not hot.

Can the proportion of vinegar to baking soda change the hardness of the crystals?

stihl88 (author)2009-10-19

Nice instructable NurdRage....

Actually, they do use Sodium Acetate in Salt and Vinegar flavoured chips. Ive tasted some of the stuff i made a couple of years ago and it definately is associated with salt n vinegar chips.

NurdRage, ive tried to download all of your clips on Youtube but it wont let me- do you know why i cant dl your clips?

NurdRage (author)stihl882009-10-19

It's about as edible as pure table salt.

No one should be eating pure table salt.

So likewise, i say don't eat this stuff, it's not toxic, but it makes about as much sense as eating pure table salt.

Most people ask about the edible thing because they intend to actually put large ice-cube sized hunks of it into drinks... not a good idea.

As for the youtube clips. I think it's because downloading them would be a form of piracy and violates the youtube terms of service. So youtube prevents that. I'm inclined to agree on some level since an offline video means i don't get any ad revenue from it.

Maybe in the future i'll sell DVDs of these experiments.

stihl88 (author)NurdRage2009-10-20

Yeah, Salt "N" Vinegar chips are about as edible as salt too!!!

As far as download ing clips from Youtube, theres actually a link inbuilt to the webpage that allows you to download the clip it's just that your clips don't want to download properly...

Not to worry i figured out how to download them with Firefox plugin.

M4industries (author)NurdRage2009-10-19

Ive downloaded vids before. No piracy involved. But Puh-Lease MAKE THOSE DVD's I WILL BUY THEM. You may run into the hassle of liabilities like the ones in steal this book and Anarchists cookbook.

Words people will think and potentially sue for.

Nurd Rage showed me how to make a bomb!
I blew my hands off making strontium nitrate!
I went to the hospital for inhaling sulfur dioxide!

I know, everyone wants to make a dollar and teach the dumb-arse people of america in the process. But lawsuits sadly get in the way.

/ M4industries

NurdRage (author)M4industries2009-10-19

When i get a HD camera i'll redo all the experiments in greater detail and maybe i'll do the DVD then. :)

M4industries (author)NurdRage2009-10-19



Thenwcp (author)2009-10-18

Very thorough, I was able to make the Sodium acetate from the first video, but this one really breaks it down. Very good.

sageserver (author)2009-10-17

cool.  i saw some hot ice paks that have a little snap button that when you press it the freezing with start.  Can you just shake the bag and it'll start?

bloke2022 (author)2009-10-17


About This Instructable




Bio: NurdRage is a dedicate group of science nerds trying to further amateur science with direct how-to instructions in video format. We saw what was already ... More »
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