Making sugar act like rocks

[Smithy]

I posted a question like this in the General forum, but was advised that the "sugar babies" tend to hang out here more. I hope someone can help me.

I want to do a little demonstration, for people interested in geology, of how a material will take on different physical properties (bulky crystals, glassy, thready) depending on how it's heated and cooled. What I'm specifically after, if I can do it, is a way to make a single pot of sugar syrup, caramel, or some other easily cooked material that I can heat and then pour into two batches. One batch sits and cools until it's hard at room temperature in a solid sheet. The other batch gets pulled or paddled as it cools, so it makes long thin threads. (Think of the tacky threads you get when you put glue between two pieces, let it almost set, then pull it apart.) The final cooled product will in one case be a bunch of long skinny threads, and the other cooled product will be a single sheet that, when fractured with a hammer, doesn't make long skinny threads. Maybe it makes hexagonal columns instead, maybe it makes little round bits. If I had a cotton candy maker this would be easy, I think, but I don't. If push comes to shove I can make rock candy for one of the examples, but that's a slower process and also doesn't make the threads I'm after.

Any ideas, anyone? I'm thinking that pulled sugar gets closest to the thready look I want, but I'm not sure how to go about it. Maybe someone else knows a better substance to cook for this demonstration.

[EllenC]

Any ideas, anyone?  I'm thinking that pulled sugar gets closest to the thready look I want, but I'm not sure how to go about it.  Maybe someone else knows a better substance to cook for this demonstration.

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Here are some links that might help

Spun Sugar

Recipe for Caramel Sauce

Toffee recipe thread

Dulce de leche

[Fernwood]

.... The final cooled product will in one case be a bunch of long skinny threads, and the other cooled product will be a single sheet that, when fractured with a hammer, doesn't make long skinny threads.  Maybe it makes hexagonal columns instead, maybe it makes little round bits.

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I think it will be easy enough to achieve your basic goal with sugar. If you pour melted sugar out and let it cool undisturbed you will get what I believe a geologist would call a glass. When you whack it, it will shatter into irregular, glassy fragments, not cleave into orderly particles. Now, if you take that same melted sugar, throw in some kind of seed particles (like granulated sugar) and stir it while it cools, I think it will end up as a solid mass of small crystals, though I still don't think you would appreciate much of the structure when you smash it. I don't know what geologists call that, but I'm thinking an example would be quartzite vs. obsidian.

An interesting project. Have fun! Fern

[Patrick S]

If you pour melted sugar out and let it cool undisturbed you will get what I believe a geologist would call a glass.  When you whack it, it will shatter into irregular, glassy fragments, not cleave into orderly particles.  Now, if you take that same melted sugar, throw in some kind of seed particles (like granulated sugar) and stir it while it cools, I think it will end up as a solid mass of small crystals, though I still don't think you would appreciate much of the structure when you smash it.  I don't know what geologists call that, but I'm thinking an example would be quartzite vs. obsidian. 

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Geologists have a term for rocks with no visible crystals --aphanitic. Obsidian is a good example. Rocks with visible crystals, for example granite with clearly visible quartz and feldspar, is said to be phaneritic.

Smithy, I don't have any suggestions, but as a geology buff I'd be interested to hear about whatever you come up with.

[Fernwood]

Geologists have a term for rocks with no visible crystals --aphanitic. Obsidian is a good example. Rocks with visible crystals, for example granite with clearly visible quartz and feldspar, is said to be phaneritic. 

Smithy, I don't have any suggestions, but as a geology buff I'd be interested to hear about whatever you come up with.

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Wow, Patrick, your geology is much more buff than mine!

Smithy, I hope you will take pictures.

Fern

[jsolomon]

With some C-clamps, rubber bands, and a buffer pad covered with some aluminum foil placed into the chuck of a drill, you could make a suitable cotton candy maker. Perhaps a dremel tool would work better, so you could spin one half of the batch (while the dremel or similar is held in the C-clamp) while the other cools to form the crystals.

One other thing you could do is divide the batch in thirds, and the third, put in a sheet cake pan and set it on some dry ice to really shock the crystals.

Good luck!

[Smithy]

With some C-clamps, rubber bands, and a buffer pad covered with some aluminum foil placed into the chuck of a drill, you could make a suitable cotton candy maker.  Perhaps a dremel tool would work better, so you could spin one half of the batch (while the dremel or similar is held in the C-clamp) while the other cools to form the crystals.

One other thing you could do is divide the batch in thirds, and the third, put in a sheet cake pan and set it on some dry ice to really shock the crystals.

Good luck!

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That sounds gloriously messy, and do-able with my equipment. Thanks for the idea!

I may also set up some syrup to make rock candy, but of course that takes a lot longer before the crystals become visible.

Edited to add: how flexible would the cotton candy threads be? Is there a good ratio of glucose to sugar that would let them set up enough to be picked up, but not be brittle?

Edited July 28, 2005 by Smithy (log)

[jsolomon]

Well, you're certainly not asking the easy questions!

Based on what I've seen in things like candy recipes and the like, if you want the sugar to remain in more of a solution, the easy thing to add it fructose (Karo syrup or the like). Based on some [faulty] recollection I would say between 5% and 10% by weight of fructose syrup to sucrose (dry). So it ends up being about 1.5 Tbsp of high fructose corn syrup to each cup of table sugar.

Now, remember that the fructose is going to hinder the formation of any and all crystals in a blanket fashion. But, it will help in the creation of the cotton candy type of stuff.

However, with the dry ice using the two sugars, you should even be able to get 4 types of crystals (possibly 5!) sucrose, L-glucose, D-glucose, fructose (possibly 2 types) and water. Good stuff, eh?

[nightscotsman]

You can make something that looks almost exactly like pummice from pastillage (which is basically just sugar with small amounts of other ingredients like gelatine and vinegar). Just put a chunk in the microwave and nuke. It will actually foam up as it melts. Stop the microwave as soon as it stops growing. It should cool quickly and will be hard and brittle.

[rooftop1000]

there is a really cheesey hot pink toy cotton candy machine available..I have one, and a cute one at Macy's 49 bucks maybe or you can rent them.

Target also carries a new brand of packaged cotton candy some sort of secret Mylar coating keeps it from dissolving.....

tracey