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Jun 08, 2022 View:

Proofing a product with sugar

I was wondering if anybody had a calculation or a teqnique to proof a flavored whiskey once the sugar was added? Please help?


If you are asking how to test the proof of your finished product then you need to re-distill a measured sample in a glass lab still. That leaves behind the sugars and other solids that cause obscuration.

But maybe that is not what you are asking.


let's say I have a proofed alcohol at 80 proof, then I add sugar and other ingredients for flavoring. That would drop the proof, right? Since the volume has changed because of the sugar and other ingredients. If so how do I now proof this spirit so I can bring it back to 80


Probably the simplest way I know of is to get an accurate volumetric flask ( these have a bulbous base and long thin neck)

Fill to a mark with 80 proof and check temperature. Add the required amount of sugar etc and let dissolve. Check temperature again and adjust to original temperature in a water bath if necessary.

Measure the increase in volume.

Add some high proof alcohol to bring that volume increase up to 80 pr. Doing this calculation with TTB tables is not easy but because you only need to add a little you could get very close with Pearsons square method. TTB tables probably won't get it right either because you are adding to a sugar solution not just water and alcohol.

(If you need help with the maths send me some numbers)

Then test with lab still. You probably won't get it right the first time.

When you get the numbers just multiply it up to your full batch, then lab still again to check.

I believe Alcodens (Meercat on this forum) is working on a calculator to assist with this problem.


Thank you PeteB I may be in touch


To give you a hint about calculating how much alcohol to add,

For the maths, assume that the increase in volume contains no alcohol. Just say the increase volume of the test flask is 7.5 mL

If you have some 190 proof then add 5.2 mL of that to bring it up to 80 proof. You now have 12.3 mL more volume.

Multiply this up to your full batch, the hardest thing to accurately will be to measure the volume of your liqueur.


Ok PeteB

I have 500ml @ 80 proof

I added 60ml of sugar and other ingredients to get the flavor profile

It brought the over all amount up to 550 ml

How much alcohol at 150 proof do I need to add to bring the product back up to 80 proof


500 ml @ 80 proof = 400 proof milliliters

400 pfml in 550ml = 72.72 proof

Not accounting for volume loss from blending,

550 mL @ 72.72 pf


X mL @ 150 pf


(550+X) ml @ 80 pf

((550 * .7272) + (X * 1.5)) / (550 + X) = 0.8

400 + 1.5X = 0.8 * (550 + X)

400 + 1.5X = 440 + 0.8X

0.7X = 40

X = 57.14 mL of 150 proof spirit should bring you back to 80 true proof. Confirm with lab still.


Thank you RobertS


bpsisk, as mentioned by PeteB above I am also trying to get to the bottom of this type of calculation. Please can you give a bit more detail on the 60 ml of sugar and other ingredients you wrote of in post #7. Was this in granular form, or was it a syrup with the sugar and other ingredients dissolved? Do you have the weight of the sugar and other ingredients? This information should help me understand how 60 ml of added ingredients caused only a 50 ml overall volume increase. The "disappearing" 10 ml can be correct under certain conditions - I am trying to find out what those conditions are. Thanks for your help.