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Rock candy


Dave the Cook
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I've got two batches of rock candy in the works. Well, I think I do. My friends derive great amusement from my usually obsessive pre-project research. In this case, however, I just relied on memory.

I made two syrups. Both are 2:1 sugar to water (by volume); one is white cane sugar and the other is turbinado. I dampened some skewers and rolled them in sugar, in order to seed them, then slid them (five each) into the syrups. Six days later, I am disappointed in my crystal crop -- I've got an eighth of an inch at best.

I might be in danger of becoming the first person in the history of the universe to fail at making rock candy. Do I need more patience? Do I need to start over? If the latter, what should I do differently?

Dave Scantland
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dscantland@eGstaff.org
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Maybe the humidity is an issue. The process depends on the water evaporating. You can use those crystals to seed the new strings to build larger crystals. The larger the starting crystals the larger the resulting crystals but it should only take about 7 days. Do you have any of the large decorating sugar to try as seeds?

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" Cook the candy mixture. (Here's where you need an adult to help!)

1. Put the cup of water into the sauce pan and heat until it boils.

2. Add 2 cups of sugar to the boiling water while stirring. Keep stirring until the sugar dissolves. (If you have a candy thermometer the temperature of the sugar water should reach 240 degrees Fahrenheit.)

3. Remove pan from heat. If you want to add flavoring or color, stir it in now."

When you made your syrups did you reach 240 degrees or just "eyeball" it?

"And in the meantime, listen to your appetite and play with your food."

Alton Brown, Good Eats

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I just bring water to a boil and add sugar until some crystals will not dissolve on the bottom (I use a clear Visions saucepan)

This is not exactly syrup, it is a super-saturated solution but has not been cooked long enough to be syrupy.

I have never used skewers, I use cotton string with a button on the end for a weight, that has been dampened and rolled in sugar. The end of the string must not touch the bottom of the jar. I either tie the top end to a chopstick or use a bindery clip to hold them.

"There are, it has been said, two types of people in the world. There are those who say: this glass is half full. And then there are those who say: this glass is half empty. The world belongs, however, to those who can look at the glass and say: What's up with this glass? Excuse me? Excuse me? This is my glass? I don't think so. My glass was full! And it was a bigger glass!" Terry Pratchett

 

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Skewers should work just as well as string, so long as they have rough surfaces and are seeded with sugar crystals in the first place. There are plenty of rock-candy skewers on the market -- I've seen them as a fancy coffee garnish in restaurants -- so it's certainly possible and, in many cases I'd think, more desirable than string.

I agree with Kayakado that you can just re-seed the skewers you already have and place it in a new solution, and a lot more crystals should form. And yes, an uncovered jar is helpful, because as some water molecules evaporate it should force some sugar molecules out of the solution. It's certainly possible to make rock candy in a closed vessel (crystal formation is not dependent of evaporation, as far as I know), however I think it works better uncovered.

Also, you mentioned that you used five skewers in each vessel. Depending on the size of the vessel, that may have been too much. I think it's at least possible that you burned up all the fuel.

I wonder how rock candy is made commercially. There must be a way to accelerate this process.

Steven A. Shaw aka "Fat Guy"
Co-founder, Society for Culinary Arts & Letters, sshaw@egstaff.org
Proud signatory to the eG Ethics code
Director, New Media Studies, International Culinary Center (take my food-blogging course)

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Well, it's humid here, but we've got air conditioning (as the incessant thrum of compressors reminds us; we're in a serious heat wave here).

I admit to using sealed containers, and I've released the lids. But I agree with Steven that evaporation, per se, isn't directly germane. I suspect that evaporation simply allows the solution to reach super-saturation (the state that andiesendi starts with). This must be the point at which crystals precipitate with abandon.

SundaySous's suggestion of heating the solution to a specific point is intriguing; perhaps conversion would have a salubrious effect.

As for process, I admit to some misdirection. After creating the syrups (which I did by applying just enough heat to allow the sugar to dissolve), I set them in a smoker and let them bathe in applewood smoke for eight hours. The temperature never exceeded 100 F. I doubt that this has anything to do with the problems I'm having, but I mention it justin case.

My formula: 24 ounces of sugar (by weight; it's about 3-1/4 C by volume) + 12 ounces of water (by volume). This makes about a quart of syrup. The containers are six-cup mason-type jars (rubber seals and lever-closures).

Dave Scantland
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dscantland@eGstaff.org
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Eat more chicken skin.

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I think the level of humidity might have a slight effect, however I grew up in western Kentucky, right on the Ohio river and it was always humid and we made rock candy all the time. (We did have problems with grainy fudge.)

Here, the humidity is usually quite low. Today it was up to 21% but a few days ago it was in single digits. Three weeks ago we had one day it was 5% and the temp was 111. Needless to say, water evaporates with extreme rapidity. I get quite large crystals in less than a week when conditions are like that.

Sometimes I suspend the strings above the jars and let them drip and the crystal surfaces dry, then put them back in the jars.

Here is another site with rock candy recipe.

"There are, it has been said, two types of people in the world. There are those who say: this glass is half full. And then there are those who say: this glass is half empty. The world belongs, however, to those who can look at the glass and say: What's up with this glass? Excuse me? Excuse me? This is my glass? I don't think so. My glass was full! And it was a bigger glass!" Terry Pratchett

 

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own!

As for process, I admit to some misdirection. After creating the syrups (which I did by applying just enough heat to allow the sugar to dissolveo see photos, please.), I set them in a smoker and let them bathe in applewood smoke for eight hours. The temperature never exceeded 100 F. I doubt that this has anything to do with the problems I'm having, but I mention it just  in case.

Get outta town! When you're smoking things and fiddling with temp, it isn't the same thing as a 3rd grade science experiment! You're doing something rich and strange. I have no SSB hints to add, and I'd like to see photos, please.

Margaret McArthur

"Take it easy, but take it."

Studs Terkel

1912-2008

A sensational tennis blog from freakyfrites

margaretmcarthur.com

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As for process, I admit to some misdirection. After creating the syrups (which I did by applying just enough heat to allow the sugar to dissolve), I set them in a smoker and let them bathe in applewood smoke for eight hours. The temperature never exceeded 100 F. I doubt that this has anything to do with the problems I'm having, but I mention it justin case.

while your temp in the smoker might not have exceeded 100 degrees, it is possible that the length of time in the smoker could be a problem. i remember during a candy making class that you can't cook sugar syrups over too low a heat for a long period of time because that allows for some of the sugar to invert and therefore inhibits recrystallization.

i hope kerry chimes in here because she would know more about this than i would.

Edited by alanamoana (log)
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Alanamoana may just have hit the nail on the head with the inversion. Could you try a batch without smoking and see if it gives you better crystals under the same humidity conditions. If it works OK then you may need to find a different way to get the smoke flavour in there. Perhaps collect the oily smoke from the top of the smoker and add some drops, though I don't know if the oil would interfere with the crystals.

I haven't made rock candy since a 6th grade science experiment and it wasn't very scientific.

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I'm not convinced about this inversion business. I realize that fructose and glucose are reluctant to crystallize, though I think it's more accurate to say that they form smaller crystals than sucrose (which might account for the small crystals I'm getting). I also understand that simply heating a sugar solution can cause inversion, though andiesenji's and SundaySous's recipes (not mention this one, this one and this one) call for substantial cooking. This one calls for repeated heating. If heat was the issue, it seems to me that none of these recipes would work, though I acknowledge that none of them suggest 100 F for eight hours.

But alanamoana's and Kerry's suggestions did make me think. Rather than slow heat, it's more common to add an acid to sucrose to create invert sugar -- in many jams and jellies, for example, invert sugar is created simply by following the recipe. On a hunch, I looked up the pH of woodsmoke. It's 2.5! (For comparison, lemon juice is 2.3.) So, exposure to an acidic compound plus long, low heat might explain what's going (or rather, not going) on.

On the other hand, I've uncovered the jars, and things are speeding up a bit, so maybe that was a big part of the problem.

Dave Scantland
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dscantland@eGstaff.org
eG Ethics signatory

Eat more chicken skin.

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Get outta town! When you're smoking things and fiddling with temp, it isn't the same thing as a 3rd grade science experiment! You're doing something rich and strange . . .

It started with a conversation I had at Tales of the Cocktail. A barkeep was talking about how smoke flavor might be added to a cocktail, and proceeded to describe a process that involved alcohol and bacon (who among us wouldn't prick up their ears?) and a sad denouement of irreducible pork fat. I suggested smoking sugar; he replied, "Great idea! Let me know when you've got some!"

I haven't sent him his share yet, but I dropped some off with a local chef, who's using it as a finish for a watermelon salad.

I'd like to see photos, please.

Not much to see, really. I didn't take photos of the smoking itself -- one thing in a Bradley smoker looks pretty much like another. But here's the stuff before the session. One quart each white and turbinado double syrups; one pound good-old Domino brown, and 1-1/2 pounds Domino white.

gallery_6393_149_34871.jpg

I stirred the syrups and raked the sugars every 45 minutes, rotating the racks at the same time.

Here's the candy as it looks now. As you can see, it's not having much trouble crystallizing at the bottom of the jar, so maybe I've also got a seeding problem.

gallery_6393_149_6748.jpg

Dave Scantland
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dscantland@eGstaff.org
eG Ethics signatory

Eat more chicken skin.

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along with the possible inversion (i still believe that the long time over low heat can cause inversion along with the acid in the wood smoke. all supersaturated syrups need to be heated, but i wouldn't say that the recipes above - which just require boiling to dissolve the sugar - call for significant cooking), stirring can decrease crystal size. you mentioned that you stirred the sugar solution several times during the smoking process. while stirring/agitation can cause crystallization in a supersaturated syrup, if you stir enough, you cause the crystals to become smaller...sort of like when making fudge...you end up with a microcrystalline structure rather than the coarse crystals you're looking for.

check out Harold McGee's section on sugar crystallization in "On Cooking" for some more information.

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I might be in danger of becoming the first person in the history of the universe to fail at making rock candy. Do I need more patience? Do I need to start over? If the latter, what should I do differently?

Being the other person who failed completely at making rock candy, I'd like an update please. I'd also like to know if it picked up a lot of smokey flavour.

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I might be in danger of becoming the first person in the history of the universe to fail at making rock candy. Do I need more patience? Do I need to start over? If the latter, what should I do differently?

Being the other person who failed completely at making rock candy, I'd like an update please. I'd also like to know if it picked up a lot of smokey flavour.

I'd also like to know if the flavor's noticeably smoky. When I was in grad school, one of the ways we'd purify a solid product was to recrystallize it. We'd usually try to grow our crystals somewhat slowly so we'd get only the pure product. If we rushed things and just let the crystals crash out of a supersaturated solution, we'd risk getting contaminants trapped along with the good stuff. Any smoky components would be "contaminants" to the sugar, and I'm curious if you're getting enough of them in your rock candy to taste a difference.

MelissaH, one-time chem-geek

MelissaH

Oswego, NY

Chemist, writer, hired gun

Say this five times fast: "A big blue bucket of blue blueberries."

foodblog1 | kitchen reno | foodblog2

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Not disturbing it is not a problem for the time being. I got called out of town, and decided just to leave the experiment in place. I may come back to a couple of solid blocks of sugar, which would be fine, as I suspect that MelissaH is correct -- that the crystallization process will force out the smoke particles. I'll just remelt it, dilute it a bit and add some over-proof rum for preservation -- make syrups, in other words.

When I took those two skewers out to photograph them, I snatched a bit of each for tasting purposes. Unlike the straight sugar, which had a nice smoky aftertaste, this seemed like plain old rock candy. But it was a small sample, and I could be wrong.

I'm fine if I end up with pure crystals. Smoked sugar and smoked sugar syrup alone have some interesting possibilities, and hey -- what's wrong with rock candy?

Dave Scantland
Executive director
dscantland@eGstaff.org
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Eat more chicken skin.

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I have to declare this experiment a draw. I left the experiment alone for a week -- not by choice, but that's just as well. There was very little crystal growth over that period; if you refer to the earlier photograph of the skewers, you'll see more or less what it looks like now. There's been some accumulation at the bottoms and tops of the jars, but that's about it.

On the other hand: the crystals that did form definitely have a smoky flavor.

So now the question is, if I can keep the temperature down and refrain from stirring (and do a better job of seeding), will I have a more clear-cut success? Or should I just be happy with the syrups? Has anyone thought up an application for smoked rock candy?

Dave Scantland
Executive director
dscantland@eGstaff.org
eG Ethics signatory

Eat more chicken skin.

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I have to declare this experiment a draw. I left the experiment alone for a week -- not by choice, but that's just as well. There was very little crystal growth over that period; if you refer to the earlier photograph of the skewers, you'll see more or less what it looks like now. There's been some accumulation at the bottoms and tops of the jars, but that's about it.

On the other hand: the crystals that did form definitely have a smoky flavor.

So now the question is, if I can keep the temperature down and refrain from stirring (and do a better job of seeding), will I have a more clear-cut success? Or should I just be happy with the syrups? Has anyone thought up an application for smoked rock candy?

Do you think it would work to make regular rock candy and then smoke it? That'd get around the heat and acid inverting the sugar syrup. I just don't have a guess as to how well the smoke would penetrate the candy.

B. Keith Ryder

BCakes by BKeith

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Do you think it would work to make regular rock candy and then smoke it?  That'd get around the heat and acid inverting the sugar syrup.  I just don't have a guess as to how well the smoke would penetrate the candy.

That's one technique I'm considering, because it eliminates the possibility of crystallization driving out the smoke particles. But as you say, we might not get much penetration.

Another possibility is to use smoked sugar to make the syrups, but that has opposite problem: we'd have great smokiness to start, but the flavor might not make it through a better crystallization process.

(On a related issue: I'm halfway through smoking a pound of isomalt powder.)

Dave Scantland
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dscantland@eGstaff.org
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Eat more chicken skin.

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Well Dave you have proven to be nothing but trouble. I can't get the damn rock candy out of my mind. *shakes fist* here are 51 rock candy recipes from cooks.com. If I'm looking through them I hope you are too.

This one mentions the use of flavored oil. Tell me Dave, tell me you can get a smokey flavor in oil, for the love of God Dave tell me you can do that.

This one looks interesting as they go the horizontal route.

When I was a kid our parents took us to a rustic resort where they made rock candy. This rock candy would have crystals as large as 3/4ths of an inch. Can't find mention of it anywhere on the net, burned down 4 years ago.

In 1970 they gave demonstrations. By then they were somewhat automated but I seem to remember someone tying knots in the string with a crochet hook. Not sure if you want larger crystals or not. I seem to remember it was a process of repeatingly dipping not sure.

Just for snicks maybe try cooling your skewers or strings. Don't know why this comes to mind I have many thoughts I have no idea where they come from.

Could you pour a sheet of hot syrup with infused oil or what ever, freeze it and the grind it?

"And in the meantime, listen to your appetite and play with your food."

Alton Brown, Good Eats

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