[massimiliano peret]

Hi everybody,
I have a probably simple question but really important for me.
As cook I create a really nice Sugar sculpture, simply mixing and boiling sugar and syroup (like the fake Sugar-Glass).
Now... the sculpture, after a couple of weeks, is melting... and off course, it's getting sticky.

Can someone please suggest me a good food (or industrial) preservative to stop the decomposition process in the next sugar sculptures?
It doesn't have to be edible, it can be toxic... since they are sculptures destinated to be showcased.

Thanks so much for any kind of help by now.

[Dan]

I think the problem here is atmospheric moisture. It's gradually dissolving your sculptures.

A possible solution is to place the sculptures in a dry container with some kind of dessicant. The easiest one to get hold of would probably be silica gel - this is used in alot of commercial packaging (shoes and guitars spring to mind). Sometimes you will find a little sachet in the packaging box that will have "Silica gel - do not eat" written on it. There are little beads of silica gel inside which soak up moisture and keep the contents dry. You may also be able to buy the beads, but if you can find free ones try it first because I can't garuntee it will work.

If you want your sculptures on permanent display, maybe you could put them under a clear bowl or in a glass cabinet on a bed of silica gel beads (it would look better than a sachet).

You may even be able to use rice as a dessicant (it is commonly added to salt shakers for this reason), but I'm not sure how effective that would be...

Good luck

[enahs]

I think Dan might be on track, in that removing the moisture might help.
Your only other option would be to use some kind of coating/varnish to protect it from the environment. The problem is that unless you gently and carefully first heated the entire structure before you coated it to remove the moisture, you would just be locking in the already existing moisture. That might not degrade as fast, or all over, but there will still be major problem spots. Using the desiccant, if it works, you could always refill it.
Also, make sure the room you keep it in is not to humid.



However, glucose reacts with oxygen to produce carbon dioxide, water and heat. I do not have my reference material with me right here, so I can not look up the energy required for that reaction to proceed, and I do not have the time right now to scour the internet for it; perhaps someone else might know/can look it up real quick. If it is low enough and this might be the problem, the easiest solution would be to refrigerate it when not on display (say, over night) in the desiccant.

[Ψ×Ψ]

However, glucose reacts with oxygen to produce carbon dioxide, water and heat. I do not have my reference material with me right here, so I can not look up the energy required for that reaction to proceed, and I do not have the time right now to scour the internet for it; perhaps someone else might know/can look it up real quick. If it is low enough and this might be the problem, the easiest solution would be to refrigerate it when not on display (say, over night) in the desiccant.

That kinda sounds like combustion.  Doubt it would happen at room temperature (or at least in the absence of an open flame?)

[enahs]

That kinda sounds like combustion.  Doubt it would happen at room temperature (or at least in the absence of an open flame?)

It essentially is. There might be some catalyst in the blood to lower the activation energy of the reaction? (do not know, not a biochemist) but it clearly does happen at body temperature (since we are all alive), which is not that far away from typical room temperatures; this means there should be enough energy at typical room temperature to make the reaction take place, at least to a minor extent (barring any catalyst).

[Yggdrasil]

The biological reactions that turns glucose into carbon dioxide and water is a complex serries of reactions (glycolysis, TCA cycle, and electron transport chain) requiring many catalysts (enzymes) and specialized structures in the cell.  Furthermore, the first few steps require an input of energy (in the form of ATP).  So, I doubt that the reaction is occuring to any appreciable extent at room temperature.

[enahs]

Well there you go. I am taking BioChem for the first time this semester (starts in a few weeks). Hard to believe I have gotten so far without it  .

[Mitch]

The reaction is of course happening. this is why old newspapers look like they've been slightly burnt. But this is a problem on the decade time-scale while we're trying to solve a problem in the week time-frame

Enclosing the sculpture with a dessicant sounds like the best idea to try first.

[Borek]

You may even be able to use rice as a dessicant (it is commonly added to salt shakers for this reason), but I'm not sure how effective that would be...

I have never decided if the rice works as dessicant or if it just helping to grind salt in case it solidifies. Probably both.

[massimiliano peret]

I want to thank everybody for the helps!
Everything sounds clear even for me, that I'm kind of far from this kind of studies.
If it will work, I will send you guys some sugar sculptures for the next christmas!

thanks

[massimiliano peret]

Hey all,
me again.
I tried the Silka-Gel, rice and even salt to stabilize the humidity,
but after two hours the sugar turned to be "melted" and sticky.

Does anybody know what kind of preservative I can mix with the sugar in the beguining of the process?
As I said before, it doesn't have to be edible, but it has to halp to stop the erosion.

Thanks

[Ψ×Ψ]

I'm not sure if this applies to sugar, but it certainly does to glass.  Desiccators aren't as effective as you'd think.  Even if you have glass straight from the oven (dry), it will absorb moisture from the air...even if you have it in a desiccator.

[Borek]

Dessicant added directly to sugar won't help. You have to keep your sugar in the glass cabinet of some kind with dessicant present inside of the cabinet (and cabinet should be airtight). That's the only way of keeping the air surrounding the sugar sculpture dry.

I don't know how you are doing these things? Perhaps there is enough time to try to add some gypsium - it may slow down shape changing.

[massimiliano peret]

Thanks for the idea of the gypsum,
I will definitely try it!
Anyway, the process is quite simple.
I melt the sugar in a pot with just a 10% of water, it stays on the fire until the water evaporates and it turns dense. At that time I just fill up the mold to give the right shape at the sugar.
That's it.
I the main time I melt the sugar in the pot I can definitely add anything, from gypsum to any other chemical you suggest. Anyway I understand that it's not possible to keep sugar outside without having a decomposition process. I just hoped in some heavy chemicals to stop this effect.

[massimiliano peret]

Do you guys think that I can use pure alcohol instead of water to melt the sugar?
I think that the reason of the decomposition of the sugar is because of the water.
The only thing is that I need to heat the alcohol to melt the sugar... do you think it's possible withou having a big fire?