Chaptalization and SG

[cghoe...@gmail.com]

Hello All,

First time chaptalizing my cider and have a question regarding SG.  After dissolving the sugar in juice and adding it to my pressed juice will the SG reflect the chaptalization allowing me to estimate the ABV as normal using my hydrometer?  The reason I ask is the chaptalization calculation and the SG post addition don't match.

Thanks

Chris

[Claude Jolicoeur]

If you have my book, this is quite well covered...

There is a difference, as the pure sugar you add will only raise the SG by this amount of sugar. On the other hand, natural apple sugar comes with other compounds that also raise SG. Hence, adding 10 g/L of sugar will bring the SG to about the same level as if the original sugar had been 8 g/L higher.

[Alexandra Beaulieu Boivin]

Hello Chris,

If I may add to Claude’s comment (and it might be explained in Claude's book as well. I don't have it with me here). 
I’ve often seen discrepancies between calculated and observed SG after chaptalization for a few reasons: Volume accuracy: Even a small error in estimating total volume throws the SG math off. Incomplete mixing: Sugar solutions can stratify; I’ve measured different SGs at the top and bottom of the same tank if the blend wasn’t fully homogenized. Sugar displacement :1 kg of sugar increases the liquid volume by roughly 0.6 L, so if you add a significant amount, the new SG doesn’t always align with a simple “before + after” math. Different SG contribution: Different sugar contribute to the SG change distinctly (circling back to Claude's apple sugars). 

Cheers,
Alexandra 

@alexandravinumartisan