I'm trying to proof liqueurs using Table 6 from the gauging manual, but instead of water, I'm using a sugar/water solution. Does the presence of sugar affect the dilution rate? This seems like a common enough scenario that the TTB might address it, but all I see in the gauging manual is for binary solutions of ethanol and water.
If the presence of sugar in the diluent renders Table 6 useless, what strategies are people using to dilute alcohol with sugar syrup?
The presence of the sugar does mean that Table 6 cannot be used directly. You have to separate the alcohol from the sugar and then use Table 6 on the sugar-free portion. This is described in a series of videos published by the TTB, which you will find at
Parts 3 and 4 of this series are what you need.
We have found that with very high levels of sugar the dilution ratios recommended by the TTB do not give accurate results. I wrote about it on these forums in the thread
For strategies to use for diluting alcohol with sugar syrup please have a look at my software called AlcoDens LQ. This page is
This software will enable you to calculate the blending ratios you need to achieve target levels of alcohol and sugar, but the TTB regulations require that you verify the final proof using the methods in the videos referenced above. This is exactly the same as for spirits without sugar, in that you cannot take the results of your proofing calculations (no matter how you do them) as being correct until you have checked the final blend with an hydrometer.
There are many threads in these forums discussing gauging and proofing liqueurs. The search function will find them for you.