# holding boiled sugar at high temperature for extended time



## westrock (Dec 5, 2012)

I'm boiling quantities of sugar and corn syrup to hard crack stage (300 degrees F.) and want to hold the syrup for a period of time at a steady temperature; a minimum of 250-275 degrees F.   I find that the syrup tends to burn when I trie to hold it at temperature on the stove-top, or oven.


----------



## minas6907 (Aug 14, 2012)

I would suggest holding it in a copper pot in a very low oven. What do you need to do with it? Depending on how fluid you need it to be, i'd set the oven to 210-230 degrees F. Regardless though, it will likely require monitoring, such as taking it in and out of the oven so it doesnt get too hot. Though I've never done it, how about putting a heat lamp over the pot of sugar?


----------



## westrock (Dec 5, 2012)

I'm pouring the boiled sugar into molds and the syrup needs to be 275 degrees F. to maintain fluid enough to run properly into the molds.  I've tried heat lamps but they don't maintain high enough temperature.  I did consider high amperage infrared heaters but have no experience with them.  I'm just not sure how stable hard crack boiled sugar is; and if it can be held at high temp.


----------



## minas6907 (Aug 14, 2012)

Then I would say a copper pan inside the oven, and your going to probably have to play with the oven temp to get it where you want. It may be a bit tricky at first, but I think you should be able to do it. The only thing I'm concerned about is over heating the sugar and it crystallizing, as can happen when pulled sugar is left under a heat lamp.


----------



## stuartscholes (Jun 17, 2013)

I think you'll have a problem doing what you suggest. When instructions tell you to heat the sugar to a certain temperature, it's less about what temperature the sugar is and more about how much water you evaporate. You need to add water to help the sugar melt and to allow impurities to be released, but you need to then evaporate the water or you will be left with syrup. Cooking to a certain temperature seems to be the most accurate way of determining the time needed for the water to evaporate (I wonder if the sugar can only reach the certain temperature when the water has been evaporated to the right degree).

With this in mind, your approach is IMO fundamentally flawed - to hold the sugar at that heat will increase evaporation and risk crystals in the sugar. What molds are you pouring into that will not work at this temperature? This is still a fairly liquid stage. Also, why are you needing to hold it at that stage? If you have your molds ready then just go for all in one go, no?

I hope you get a chance to reply as I'm interested to know what you're trying to do - I love a challenge.


----------



## westrock (Dec 5, 2012)

Thank-you for the reply D,

The boiled sugar is going into silicone moulds.   The boiled syrup works best poured into silicone moulds when it's at the lowest possible temperature that will keep it liquid enough to fill the moulds properly.   In order to save on the number of moulds required I was looking for a way to hold the syrup at temperature while the moulds are filled, cooled and then used again.  Any ideas  .......George


----------



## stuartscholes (Jun 17, 2013)

Are these flat moulds or 3d moulds? Also, what quantity of sugar are you using?


----------



## westrock (Dec 5, 2012)

The moulds are both flat and 3D, the batch is usually 6 cups sugar and 2 cups glucose (corn syrup)


----------



## petemccracken (Sep 18, 2008)

I'm curious, why not cut the recipe in half, or possibly a third, and avoid having to hold the sugar?


----------



## westrock (Dec 5, 2012)

I was looking to hold the sugar as a way to stabilize the pour temperature.  I'm finding that boiled sugar poured into silicone moulds works best within a narrow temperature range.  If the sugar is too hot then there are bubbles in the product, and if too cool the moulds may not fill properly or quickly.  As I pour hard crack sugar into moulds from a copper vessel the temperature of the sugar travels through a range, and the resulting product is not consistent.


----------



## stuartscholes (Jun 17, 2013)

I can see why you wouldn't want to make small batches, it's quite laborious. However, I'm really struggling to see what the issue is here - I've never had any problem with pouring sugar into molds unless they're REALLY small. Any chance you can take a photo or two of what you're doing. Sorry to be a pain, I really want to understand your problem and help you get a solution.


----------



## jcakes (Feb 18, 2007)

If I may, the amount of aggravation you are going to spend on figuring out a solution might be eliminated if you purchase a few more molds.  I used to think I couldn't afford a second bowl for my Hobart; then I got one and realized how dumb I'd been.  Spending $200 for another bowl allowed me to increase my production and saved me a lot of time and was worth the investment within the first month I had it (this was 10 years ago when I was just starting out).  So if the cost is not so prohibitive, I'd suggest buying another few molds if you can.


----------



## westrock (Dec 5, 2012)

The problem is not the size of the moulds; it's the detail within the moulds. If the hard crack sugar is too cool the detail is not picked up. If the sugar is too hot, the casting picks up the moisture bubbles on the surface. The pic of the sun shape details the bubbles from sugar too hot the other image of an eagle shows a much clearer casting from a cooler pour. The problem is finding a system to hold or stabilize the syrup so that each casting is consistent.





  








DSCN3910.JPG




__
westrock


__
Aug 2, 2013












  








DSCN3912.JPG




__
westrock


__
Aug 2, 2013


----------



## stuartscholes (Jun 17, 2013)

You seem to experiencing a strange phenomenon here. When I pour sugar onto my silpat and move it around to cool it, it takes a good 5 - 10 minutes to become anything like cool enough to be solid (and that's with TRYING to cool it). I then use this as pulled sugar. If I'm casting sugar I take my pan off the heat for a couple of minute to let the violent heat dissipate, then I pour it straight from the pan into the mold. If there are any air bubbles on the surface (of the sugar) then these are easily removed by running a blowtorch over them.

I can't see what side your bubbles are on, so it may be as simple as the above to get rid of the bubbles. What are you standing your mold on? Where do you live (i.e. what is a rough average temperature)? How do you pour your sugar?

Try having a look at the techniques that Stephane Treande uses to pour in this video: 



. I'm sure he's working with isomalt, but it's ok, it'll still work.


----------



## westrock (Dec 5, 2012)

Th The bubbles on the castings are moisture bubbles that form on the mould surface side of the casting. The higher the temperature of the pour the more bubbles are produced. Silpat does not produce these bubbles because the silicone is extremely thin and it has a layer of fiberglass that does not absorb moisture. I've never worked with Isomalt because of the expense but apparently Isomalt can be held in an oven up to three hours before it starts to turn from clear to a yellow shade. The lower the holding temperature, the longer it can be held without discolouration. I'd really like to know what the pour temperature is in the video by Treande. I find that regular sugar turns brown very much faster than three hours when put into a 275-300 oven. It may just be the nature of the beast; it's possible that regular boiled sugar has to be cast as soon as possible, and holding it at heat changes it's physical characteristics.


----------



## stuartscholes (Jun 17, 2013)

Does that mean you're heating your sugar in the oven as opposed to your hob? Either way, if you get a way to cast clear sugar I'd be grateful to hear it - I've been experimenting and I'm pretty convinced it cannot be done.

Holding the sugar will definitely change its characteristics. As I said before, you add water to facilitate the melting and purification process and then evaporate it off. Obviously an temperature above 100 degrees C (which is far more than your sugar will be at - you'd be working at around 60 degrees to pull loose sugar, so pouring is a lot higher) will continue to evaporate the water, thus changing the chemical characteristics.

How big are the molds out of interest? There's nothing to give any idea of scale and the only reason I can think of that would cause them to not take the detail is if the molds are cold, on a cold surface and small. I'll have to try casting into silicone a bit more (although I've not had problems before) as opposed to on my silpat. This problem is really bugging me, I want to know wha is going wrong!


----------



## westrock (Dec 5, 2012)

I make the moulds myself with food safe silicone. Silicone is a polymer and absorbs water quite quickly . If the moulds are heated to 300 degrees F. the absorbed moisture vaporizes from the moulds and if the hard crack sugar is on the cool side the casts are much better. If the hard crack syrup can be held around 250 degrees F. and poured into a dry mould the results are very good. My problem is finding a way to hold the syrup at a steady temp of 250, both to improve casting and also to make it easier to handle without the rush to pour before it's too cool. I'm assuming that the silicone that I'm using is typical and the problem with moisture is not unusual for food grade silicone. There are various amendments made to Silicone to improve it's moisture absorption but most don't seem to be food compatible.





  








DSCF1584.JPG




__
westrock


__
Aug 2, 2013


----------



## petemccracken (Sep 18, 2008)

Have you tried holding the *molds* at 250°?

That might eliminate the "water problem".


----------



## westrock (Dec 5, 2012)

I do hold the molds at 250+ degrees; I have to in order to eliminate the bubbles.  I was looking for a way to hold the syrup at temperature as well just to settle the process down so that the fluctuating temperature of the syrup wasn't dictating the  entire casting process.


----------



## petemccracken (Sep 18, 2008)

OK, my apologies, I missed that part.

Now I have a question.

Water evaporates, turns to steam at 212°F (100°C), so, if the molds are at 250°F(121°C) as is the sugar, where's the water coming from? There shouldn't be any, should there?


----------



## westrock (Dec 5, 2012)

You're right there should be no moisture on the castings if the moulds have completely dried.  The nature of silicone may allow some moisture to remain but usually if the moulds are dry the castings are good and the castings get better as the syrup gets cooler.


----------



## stuartscholes (Jun 17, 2013)

Sorry to say, but I can't see a way to hold the sugar at such a high temperature for a reasonable amount of time without screwing it up. I think your best bet is going to be more molds. I feel a bit frustrated to say that (I like to work around problems) but I just can't see how it can be done. Sorry to say.


----------



## westrock (Dec 5, 2012)

It's possible that the better strategy is to boil smaller batches, and just cycle the entire process quicker.  Appreciate the input, and I thank-you for that.


----------



## stuartscholes (Jun 17, 2013)

No problem, sorry I couldn't help more.


----------



## jcakes (Feb 18, 2007)

I was flipping through my Pfeil and Holing catalog and the page fell open to the section with their new stock of Isomalt sticks and tools - and there was an Isomalt holder - it had a note that said it won't melt isomalt, it was just for holding it at a fluid temp and I wondered if this might be useful. It looks small to me, but perhaps there's a professional version of it somewhere. Here is a link to it:

http://www.cakedeco.com/cgi-bin/webc.cgi/st_prod.html?p_prodid=12883&p_catid=&page=3


----------



## westrock (Dec 5, 2012)

Appreciate the link, Isomalt is a little easier to hold than regular sugar apparently; but it's interesting to see an appliance dedicated to the task.


----------

