We have just attempted our first batch of wine from concentrate
(Alexander's Sun Country Zinfandel) and have discovered in the process
that the gravity conversion information on our hydrometer does not match
the gravity conversion table in the book "Progressive Winemaking."  The
"specific gravity" and "brix" line up, but the potential *** content
is off.  For example, our initial hydrometer readings, after mixing
concentrate with water were:
specific gravity=1.050
brix=12.5
hydrometer's potential ***=6.7%
book's potential ***=8.0%

after adding 11 cups of sugar (this seemed like a lot!) they were:
specific gravity=1.080
brix=20.0
hydrometer's potential ***=10.5%
book's potential ***=12.8%

We want to get to approximately 11.5%  Can anyone help us figure out
what's going on?  Could there be some conversion factor we need to apply
to the table in the book?  Thanks!

Quote:

> after adding 11 cups of sugar (this seemed like a lot!) they were:
>         specific gravity=1.080
>         brix=20.0
>         hydrometer's potential ***=10.5%
>         book's potential ***=12.8%

> We want to get to approximately 11.5%  Can anyone help us figure out
> what's going on?  Could there be some conversion factor we need to
> apply

Remember that the book is giving you potential ***.  This doesn't
mean that your particular yeast will be able to take your wine to this
*** level.  Also, what type of wine are you after, dry/semi/sweet?
This will play a role in how far you let the fermentation go.  Right now
you seem to have a good sugar content.  If you start the fermentation now
you may see it terminate at 11.5 - 12.0 anyway.  However, if you keep
checking *** content when fermentation slows you can always chill the
wine to kill the yeast when you arrive at your desired % ***.
Remember to get below 32 degrees to kill the yeast instead of just making
it go dormant.