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KNO3 + sucrose solubility


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Posted

Hi. Simple question here that I couldn't find anywhere else on this website. How many grams of water do you need to dissolve 100 g of R-Candy (65:35 mix).

 

I just don't want to waste time boiling off water I don't need.

Posted

Check Jimmy Yawn's site. He's the inventor (or at least 'perfecter') of the "recrystallized R-Candy" method, and his site gives you all the info you need.

 

Lloyd

Posted (edited)

I don't know the exact amount, but it is suprising how how little water is needed to dissolve R-Candy when it gets hot. The only result of using too much water is increased cooking time, so I never was too concerned about the amount of water I used, as long as it completely dissolved my mix. If I had to guess, I would say I use about 175 ml of water for a 100 gram batch

Edited by MadMat
Posted (edited)
Yah nice idea but looking into it he uses corn syrup which has a lot of water in it. I should probably posted this in the Chem section but I can probably relearn a little chemistry myself for the sake of it. Edited by JMan
Posted

Hmm I should have 175-200ml.

Posted (edited)

I just did it at 20 degrees celcus and you get 219 ish but at 100 celcus it should be about 20 grams? I can't be right

 

Off to the chemestry section. I'll be back

Edited by JMan
Posted

Are you talking about the weight of the water?

Posted
Weight or volume it's the same with water so it didn't really matter. I'd use weight cus you use a scale to make all the other parts of r candy
Posted (edited)

I was a bit confused because (I see now) you were talking about total weight of chemicals + water. O.K. If you want to follow what I do, weigh your chemicals (65g KNO3 and 35g sucrose) 100g and add water to 275g total. It won't all dissolve until the water is up to 90-95 C but stir as it heats up. IF by some chance it doesnt all dissolve by the time it is up to 90-95C add another 15-20g water. That should be more than enough to dissolve everything. Stir while it is cooking. Continue to cook the mixture until it no longer bubbles or hisses. You want to make absolutely sure all the water is boiled off. You will also notice that it will start to actually smell like candy when it is done. Watch the color! If it starts to turn brown, it is starting to caramelize and then you are going too far. A little bit of caramelization is O.K. and probably unavoidable, but if it goes to far you will start to lose performance as caramelized sugar has a much lower fuel value. Pack the mixture into your tubes and your done. One trick I have used is to line the inside of the top of your tubes with masking tape (like the top 3/4" of the tube). This will prevent the R-Candy from sticking to the inside of the top of the tube as you fill it. R-Candy stuck to the id of the top of the tube can cause bulkhead failure. Once you have filled the tube, peel the tape off and you have a nice clean surface that will hold the bulkhead in place.

Edited by MadMat
Posted
Madmat I get the whole process I was just wondering if that much water is actually needed. I just want to cut down on the time it takes to boil all the water off. Make it a little more systamitc if you will, rather than guessing it's enough water once it gets up to temp.
Posted

I was just being thorough :D . Seriously though, you can start out at less than 175 ml if you want. If it doesn't all dissolve just add more. Yes I can understand trying to make your process as efficient as possible, but keep in mind, a little extra water won't hurt anything and just cost you a few more minutes of cooking time.

Posted
I know but a few extra mins is a few mins of daylight for me. It takes me about an hour right now. Just trying to do the fastest SAFEST way possible (so no I don't turn my heat up past 165 C ever)
Posted

Solubility of Sucrose: 179 grams per 100 milliliters of water at 20 degrees Celsius.
KNO3 is about 90 grams per 100 milliliters of water.

Which is increased as the temperature is increased.

Posted (edited)

Just tried it and yes. With 35 grams of water it will disolve completely before boiling the water.

 

This is going to make rcandy so much easier for me a 100 gram batch now only takes 10-15 mins to cook dry.

 

Hope this helps anyone else boiling water off for an hour.👍

Edited by JMan
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