William Frazier wrote:
You have about 12.1% v/v alcohol.

Please explain the 12.1% computation.
Dick

Dick - This has been discussed a lot recently. Here's the formula I use;
Reference: Homebrewing, Volume 1 by Al Korzonas
Page 31

Calculation of alcohol by weight;
% ABW = (OG - FG) x 105

Calculation of alcohol by volume;
% ABV = ABW x 1.25

Combined method for alcohol by volume;
% ABV = (OG - FG) x 131.25


OG refers to original specific gravity. FG refers to final gravity or the
specific gravity when fermentation is complete. It's my belief that you
can't ferment more sugar than is in the wine to begin with. So, the FG
should be considered 1.000. The fact that we observe specific gravities
less than 1.000 is because of the presence of alcohol and the way it
effects the hydrometer. Therefore, when I calculate alcohol content I
always use a FG of 1.000.

In R-D-C's case;
%ABW = (1.092-1.000) x 105 or 9.66%
%ABV = 9.66 x 1.25 = 12.075 or 12.1%

Bill Frazier
Olathe, Kansas USA

Hi Bill

Neither of these methods work. As you have already indicated, the
Korzonas method doesn't compensate for the effect of the alcohol on
total drop. And - your method of substituting 1.000 for any and all FG
readings simply ignores the fact that there is a_big_difference between
an FG of say 0.984 and say 0.995. In fact, all your method does is
recalculate the original PA value. Do some "sanity checks"and you will
see this is true.

Of course, if the wine goes dry, this will be the correct answer, BUT_only_
if the wine goes *dry* !! This being the case, why bother with a
calculation at all when all we have to do is use the original PA as our
end alcohol value for *DRY* wines ?? HTMS

Frederick