I know this one gets debated a lot and don't want to start an argument but
was trying to work out the alcohol content of my latest concoction.
I started with SG 1.092 giving PA of 12.5%.
Finished at 0.984.
So, do I have a 12.5% abv wine or do I use the total drop of SG giving
This is only for the label on the bottle for when I give a couple of bottles
away. Main thing is even before any aging it tastes great! Definitely my
best batch yet.
and you can find
a formula that works for me. To get me in the ball park I just subtract
finished SG from the beginning SG, for get the decimels and devide by
7. That is close enough for me. Using my rounding system your alcohol
level would be 15.4%. Useing the correct ffigures it would be 108/7.04
"R-D-C" Royal De-Canter? wrote (in part):
Dick - This has been discussed a lot recently. Here's the formula I use;
Reference: Homebrewing, Volume 1 by Al Korzonas
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%
Olathe, Kansas USA
Got back to find so many posts that I decided to reset my reader and get
a fresh start. Senior moment (don't ever get old) 'cause now I can't find
the threads I was watching. Will do my best to answer those I can find.
You have about 12.2%ABV in that wine. However, with an end reading
of 0.984, I would *guess* that this is a "Country" (non-grape) wine and
that there *may* not be enough acid in it. If this wine were mine, I would
re-check the pH immediately. If I found that it was higher than ~3.5, (ie
4.0) I would adjust_both_acid and SO2 to achieve an "aseptic" level of
molecular SO2. If my *guess* turned out to be wrong, at least I would
be satisfied that my wine would "keep". HTH
PS - Let me add this in here. About all that most "modern" winemakers
do is hammer all their ferments down to as close to bone dry as they can
get them and either leave them that way or stabilize chemically and
re-sweeten later. For these folks there is no *need* for end alcohol
calculation since the original PA already tells you how much alcohol will
be in that wine _if_ and _when_ the wine goes DRY !! (eg when all of
the sugar is consumed). So - for all of these folks, all they have to do
is use the original PA number for their "end alcohol" value and print that
on the label. (assuming there have been no subsequent dilutions) This
stuff is *REALLY* easy if you will just let it be. This works because
this is exactly what our hydrometers are designed to do for _practical_
The only time alcohol (and RS) calculations are_needed_is when a ferment
_doesn't_go dry. (eg for RS ferments and/or "stuck" wines) Even for
"stuck" wines, this isn't really necessary if the maker is determined to
re-start the ferment and hammer it the rest of the way down to dry. About
the only thing it tells him is whether a re-start is feasible or not.
Which pretty much leaves us with only "old fashioned"
RS ferments to worry about. So - for all those who only do "modern"
ferments, forget about all this foolishness and just use the PA number
to print on the labels of your *DRY* wines !! Of course, for wines
that are fermented dry and then re-sweetened, subsequent dilutions
will have to be calculated. HTH and HTMS
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
"...the Korzonas method doesn't compensate for the effect of the alcohol on
Frederick - I only have narrow range hydrometers. They don't have a PA
scale so Korzonas method and a FG of 1.000 gives me a reasonable number.
Olathe, Kansas UsA
I am confused about your "modern" and "old fashioned" winemaker
designations. Frankly they are silly and artificial. If one wants to
make fine wines there are few ways to do that regardless of whether or
not one is a home winemaker or a professional. Period!
Your long and arduous posts about PA, alcohol content and other minutia
are exercises in "reductio ad absurdum" For example, we have 400
gallons of Pinot Grigio that currently has an RS value of 0.67, a pH of
3.41 and a TA of 0.610. It also has an alcohol level of 15.1%. The
starting Brix was 25 degrees and the theoretical alcohol calculates to
14.3-14.5% . Accounting for this is dependent upon quite a few factors,
and is best theft to the theorists on this thread for the moment. Other
considerations are easier to understand. It seems to me that in all of
your theoretical considerations you are neglecting the fact that the
newer yeasts (ICV D254, ICV D21 and ICV D80 for example) convert sugars
far more efficiently and effectively than some of the older yeasts that
have been used for years. Thus a must that would have yielded a 12.5%
alcohol level using older style yeasts can now result in a wine of
13.5-14% alcohol content starting at the same Brix level.
Similarly a Rose we made from Pinot Noir, picked at 26 Brix, managed
only a 14.72% alcohol level even though the RS was 0.07. Why?
Different yeast (Lallemand SVG). The theoretical PA was 15.1. Was this
yeast an underachiever? No because it did what we wanted and resulted
in fruit forward and rather lush wine with a variety of floral
All of these data resulted from laboratory testing in a major USA winery
My point is that while all of these theoretical considerations are
intellectually interesting, they seem to be of little practical value.
The alcohol content of the finished wine is the alcohol content in the
finished wine, regardless of what one calculates it to be a priori.
Are you condemning us "little guys" to eternal darkness ?? I would rather
light a candle. Comments interspersed:
I had thought that I had made the distinction very clear - but - if not, let
me do so now. "Modern" methods evolved with the advent of chemical
stabilizers (and sterile filtration). "Old fashioned" refers to the methods
used before these things came into general use. Two very different worlds.
You obviously understand "modern", so let me point out an example of
"old fashioned". I believe the best known example is CJJ Berry's book
"First Steps in Winemaking". (Suggest you get a copy). If you look in
the index you will_not_find any reference to chemical stabilizers or sterile
filtration (keep this in mind when reading the text). And yet, in his
section, you will find LOTS of sweet (RS) wines. I can assure you that
his wines_were_stable in the bottle !! Folks in this group often ask
how they can make a sweet wine without using sorbate. My answer
to them is to do it the "old fashioned" way. Silly ?? Nope. Lots of us
"old timers" did (and still do) these kinds of RS ferments.
If, after reading Berry's book, you still think that such distinctions are
"...silly and artificial...", well - I guess you are welcome to your
I understand that folks who work only with "the grape" often share this
opinion. One need only look at the long lists of "country" (non-grape)
recipes to discover that there are_lots_ of ways to make "fine" wines.
Actually, my estimate for 25BRIX is more like 13.6%. 14.3% would
indicate a starting BRIX of ~26. And 15.1% would be a little over
27.5. Is there something wrong with both my references AND
my hydrometer ?? I have been using both for a _very_ long time.
Has something changed in the mean time ?? If so, maybe you should
inform UCDavis that the info on their site is wrong because their
info supports the numbers I have been using for all these years. They
have a "contact" address on their site. Please let us know what they say !!
Either way, this is obviously non-typical, and, if I had used a "typical"
yeast, I think I would_start_by questioning my own original BRIX
reading thinking that I must have taken that reading after the ferment
had already started.
I agree. And a winemaker with a little extra time on his hands should at
least make an effort to figure out why.
Not familiar with these yeasts but I promise I will look into it.
The fact is, that in the references we have been using here, not one of them
states that their numbers are only for specific "non-typical" yeasts. Most
of them _do_ state that the numbers are representative of typical ferments
using typical yeasts !! These numbers and our hydrometers are about the
only tools that us "little guys" have and I doubt you will convince any of
that we should simply abandon the use of these tools in our efforts to make
The *REALISTIC* PA for an _average_ ferment of a 26BRIX must is
~14.3. I need only look at my triple scale hydrometer to confirm this.
UCDavis uses an "efficiency/conversion" factor of 0.55. Thus,
26*0.55 = 14.3 and once again, my hydrometer agrees. Many sources
tell us that the accuracy of such estimates is ~0.2% ABV. It is not unusual
at all that ferments might finish lower than such an estimate. What _would_
be unusual, would be to have them finish substantially _higher_. Which, by
the way, is what all of our previous discussions have been all about.
I suspect that the lab results only covered the "after ferment" data. I
suspect that the original BRIX data may have trusted field survey reports
or were taken after ferment had begun. No other way I can think of to
explain these kinds of anomalies.
Sorry. I thought I was trying to_stress_practical applications.
True. But us "little guys" don't use lab reports and _we_ need some
kind of way to come up with realistic estimates. What do you suggest
PS - Believe it not there is no malice in my comments here. I really
_am_ only trying to be helpful.
Margalit in Concepts in Wine Chemistry (2004) uses conversion factor of
0.57 for initial Brix and refers to several references (actually people
from UC Davis) that report the conversion factor to be measured between
0.60 - 0.55 in practical fermentations. According to this info, the
0.55 is the most conservative estimate and Jerry's numbers, although on
the optimistic estimate side, fall within this range.
I've also heard from a professional winemaker here in BC that they were
getting higher final alcohol values for initial Brix measurements than
5-10 years ago. She also thought this was because the current "designer
yeasts" were getting more efficient in alcohol production.
Also, keep in mind that most references for the conversion factors are
not recent, so if there was a recent increase in yeast efficiency, this
might not be reflected in the typical PA fomrmulas in use.
My main question to Jerry would be - how are the wines tasting? That's
pretty high alcohol, especially for the Pinot Gris.
I wish I knew what all that meant :-)
It is an apple wine made from a recipe base on that from CJJ Berry's First
Steps... I added a blend of acids as per his instructions but didn't check
the acidity. (Will have to get an acid test kit).