66% sucrose test solution off by 13.5 brix?

[NW Ohio]

OK, just out of curiosity I made a 66% sucrose test solution; 660 grams of table sugar in exaclty 1 liter of distilled water. I poured this into my test cup at room temperature (21.1 C, 70 F), lowered the hydrometer to between 65 and 66 brix where I thought it should float, left go, and it promptly sank to 52.5 brix.

Everything I have read says that syrup sugar is mostly sucrose (table sugar). That looks to be true based on this study, "SUGAR PROFILES
OF MAPLE SYRUP GRADES", http://www.uvm.edu/~pmrc/sugarprof.pdf.

...so what gives? Why am I off 13.5 brix?

[happy thoughts]

Maybe I'm not thinking correctly, but something seems wrong with your solution. I'm thinking you should have only added enough water to the sugar to make a liter. It seems to me that you may have made more than that by volume as the sugar would add to the volume.

[NW Ohio]

Oops, I read that post about 5 times before I posted it to make sure I had it correct and still didn't catch that. You are correct, I used the distilled water to bring the solution to a final volume of exactly 1 liter.

[jnmartin]

I think you have to stick with the same units of measure. ie. since brix and % both are related to weight then you need to measure the water by weight not by liquid measure. So, to 660 grams of sucrose add 340 grams of H2O, dissolve all the sugar into solution and see how it works for ya..

[happy thoughts]

I think you have to stick with the same units of measure. ie. since brix and % both are related to weight then you need to measure the water by weight not by liquid measure. So, to 660 grams of sucrose add 340 grams of H2O, dissolve all the sugar into solution and see how it works for ya..

I think that's the answer because going by weight of a liter of syrup (1.33 kg), sugar content by % of weight should be about 870 grams/liter.

[lpakiz]

So to check my sap hydrometer at 4%, I put 4 grams of sugar in 996 grams of water? Or is it 40 grams in 960 water?

[jnmartin]

So to check my sap hydrometer at 4%, I put 4 grams of sugar in 996 grams of water? Or is it 40 grams in 960 water?

It would be 40 grams of sugar in your case but personally I wouldn't get too excited about coming up with a correction from using a homemade test solution unless you think your hydrometer is grossly in error. There's just too many places to introduce error.

[Beweller]

You need 660 grams of sucrose and 340 grams of water. 66 percent is WEIGHT percent: 660 grams of sucrose in 1 kg of SOLUTION.

[NW Ohio]

Sounds like that might make more sense. I'll give it a shot. Thanks!

[pdr]

NW Ohio, did you give it another try?

[NW Ohio]

Yes. I mixed 330 grams of sucrose with 170 ml of distilled water (1 ml = ~1 g). Heated to dissolve the sugar. (I know most here are not suprised by this but that's a bunch of sugar in a small amount of water.) Then I brought the final mass back up to 500 grams with water. Like before I lowered the hydrometer to 66 brix, released it and it floated to 65.5 brix. Adjusted to room temp. that comes out just about perfect.

Then just, because I can be a dork sometimes, I boiled the first solution I made down until the bubbles looked "right" (then went a little farther). I left it cool and found it to be 72 brix (forming lots of crystals at room temp). I figure that means if I put 83.3 ml of water back in I will have it at 66 brix also (haven't done this yet).