The final SG of a wine fermented to dryness has to account for the fact
that the alcohol in the wine is less dense than water. That's why the
dry wine has an SG less than 1.000. A wine at SG 1.000 is not quite dry.

Gene

jim wrote:
Heh sorry to miss you out. Thanks for the info.

I understand that PA starts with the potential. What I am getting at
is that SG and PA are given a common correlation as being discussed in
this thread. Yet, SG works on total movement (from initial to final
SG). So, what is the difference between a wine with PA of 15 that
finishes at SG 1.000 and a wine with a PA of 15 which finishes at
0.990?

That still *weirds me out* Many thanks and I hope this isn't too off
topic.

Jim

On Nov 27, 1:04 am, pp wrote:
Why is everybody calling me Joe these days? :-p

As for the 0.990 vs 1.000 difference, basically, you can think about
it as the table being designed so that instead of using the difference
between the starting and final sg points, you're only using the
starting point. In other words, the table is built with the assumption
that your wine ferments completely to dryness (because that's what PA
means) and gives you the PA values with that assumption.

Pp

On Nov 26, 1:37 pm, jim wrote:

I use this table:http://www.brsquared.org/wine/CalcInfo/HydSugAl.htm
which backs paul and joe's comments.
I have to admit though, I never quite understood how this can be if
0PA is 1.000 and I usually ferment down to around 0.990
Jim
On Nov 26, 8:36 pm, pp wrote:
On Nov 26, 11:46 am, "Paul E. Lehmann" wrote:
Joe Sallustio wrote:
Hi. Is there a special starter I should use to
re-start this? Room temperature shouldn't be
an issue - it's being kept in my pantry so it
is always warm enough.
Steve's post already gave you great advice and
the correct value of
'potential alcohol' for 1.100SG. (My tables
came from NBS so I know
they are right.) The only thing I would expand
on is the amount of
time to give it to get going. Starters need to
get going really well
before you add them to the total volume. I
keep doubling the volume of the starter and let
it get back to fermenting strongly.
13% ABV for an apple wine might be a little
heavy duty; if this died at around 9 or 10 % I
might be happy with that. I show that as 1.022
to 1.029 S.G.
bobdrob,
I show 1.115 as 19.3 % ABV; I have the book at
home that probably
takes them higher; I have spreadsheet I made on
my work PC. I can email you the spreadsheet.
Joe
Joe, are you sure of that? I quick check on my
program shows 1.115 SG to be equivalent to 15.78
Brix and the PA to be 15.78- Hide quoted text -
- Show quoted text -
Same here - don't have the tables on me but last couple of years we
got some Zin and Petite Sirah grapes that were over 1.130. I remember
checking the PA on those and even that was definitely under 20% - not
that we fermented them that way!
Pp- Hide quoted text -
- Show quoted text -

my lexdyksic abinility to dear a dryhometer notwithstanding, i'd appreciate
a copy of that spreadsheet. thanks joe!



"Joe Sallustio" wrote in message
...

Hi. Is there a special starter I should use to re-start this? Room
temperature shouldn't be an issue - it's being kept in my pantry so it
is always warm enough.

Steve's post already gave you great advice and the correct value of
'potential alcohol' for 1.100SG. (My tables came from NBS so I know
they are right.) The only thing I would expand on is the amount of
time to give it to get going. Starters need to get going really well
before you add them to the total volume. I keep doubling the volume
of the starter and let it get back to fermenting strongly.

13% ABV for an apple wine might be a little heavy duty; if this died at
around 9 or 10 % I might be happy with that. I show that as 1.022 to
1.029 S.G.

bobdrob,
I show 1.115 as 19.3 % ABV; I have the book at home that probably
takes them higher; I have spreadsheet I made on my work PC. I can
email you the spreadsheet.

Joe

Hi Gene, alcohol is definitely less dense than water, but if a wine at
1.000 is not quite dry, why do they calibrate 1.000 with 0PA? Do you
see why I think it is confusing?

Jim

On Nov 27, 9:34 am, gene wrote:
The final SG of a wine fermented to dryness has to account for the fact
that the alcohol in the wine is less dense than water. That's why the
dry wine has an SG less than 1.000. A wine at SG 1.000 is not quite dry.

Gene

jim wrote:
Heh sorry to miss you out. Thanks for the info.

I understand that PA starts with the potential. What I am getting at
is that SG and PA are given a common correlation as being discussed in
this thread. Yet, SG works on total movement (from initial to final
SG). So, what is the difference between a wine with PA of 15 that
finishes at SG 1.000 and a wine with a PA of 15 which finishes at
0.990?

That still *weirds me out* Many thanks and I hope this isn't too off
topic.

Jim

On Nov 27, 1:04 am, pp wrote:
Why is everybody calling me Joe these days? :-p

As for the 0.990 vs 1.000 difference, basically, you can think about
it as the table being designed so that instead of using the difference
between the starting and final sg points, you're only using the
starting point. In other words, the table is built with the assumption
that your wine ferments completely to dryness (because that's what PA
means) and gives you the PA values with that assumption.

Pp

On Nov 26, 1:37 pm, jim wrote:

I use this table:http://www.brsquared.org/wine/CalcInfo/HydSugAl.htm
which backs paul and joe's comments.
I have to admit though, I never quite understood how this can be if
0PA is 1.000 and I usually ferment down to around 0.990
Jim
On Nov 26, 8:36 pm, pp wrote:
On Nov 26, 11:46 am, "Paul E. Lehmann" wrote:
Joe Sallustio wrote:
Hi. Is there a special starter I should use to
re-start this? Room temperature shouldn't be
an issue - it's being kept in my pantry so it
is always warm enough.
Steve's post already gave you great advice and
the correct value of
'potential alcohol' for 1.100SG. (My tables
came from NBS so I know
they are right.) The only thing I would expand
on is the amount of
time to give it to get going. Starters need to
get going really well
before you add them to the total volume. I
keep doubling the volume of the starter and let
it get back to fermenting strongly.
13% ABV for an apple wine might be a little
heavy duty; if this died at around 9 or 10 % I
might be happy with that. I show that as 1.022
to 1.029 S.G.
bobdrob,
I show 1.115 as 19.3 % ABV; I have the book at
home that probably
takes them higher; I have spreadsheet I made on
my work PC. I can email you the spreadsheet.
Joe
Joe, are you sure of that? I quick check on my
program shows 1.115 SG to be equivalent to 15.78
Brix and the PA to be 15.78- Hide quoted text -
- Show quoted text -
Same here - don't have the tables on me but last couple of years we
got some Zin and Petite Sirah grapes that were over 1.130. I remember
checking the PA on those and even that was definitely under 20% - not
that we fermented them that way!
Pp- Hide quoted text -
- Show quoted text -

On Nov 26, 2:46 pm, "Paul E. Lehmann" wrote:
Joe Sallustio wrote:

Hi. Is there a special starter I should use to
re-start this? Room temperature shouldn't be
an issue - it's being kept in my pantry so it
is always warm enough.

Steve's post already gave you great advice and
the correct value of
'potential alcohol' for 1.100SG. (My tables
came from NBS so I know
they are right.) The only thing I would expand
on is the amount of
time to give it to get going. Starters need to
get going really well
before you add them to the total volume. I
keep doubling the volume of the starter and let
it get back to fermenting strongly.

13% ABV for an apple wine might be a little
heavy duty; if this died at around 9 or 10 % I
might be happy with that. I show that as 1.022
to 1.029 S.G.

bobdrob,
I show 1.115 as 19.3 % ABV; I have the book at
home that probably
takes them higher; I have spreadsheet I made on
my work PC. I can email you the spreadsheet.

Joe

Joe, are you sure of that? I quick check on my
program shows 1.115 SG to be equivalent to 15.78
Brix and the PA to be 15.78

Hi Paul,
Yes, I'm sure to a rounding error. I have the book now. Baume
(modulus 145) is what most people refer to as 'potential alcohol'. I
show 34.3 brix =1.14985 S.G. =18.90 Baume 145 at 20C.

I really think the confusion comes from two places.

One, alcohol concentrations can be measured by volume (V/V or ABV) or
weight ABW) . Most refer to ABV now and don't mention ABW. ABW is
about 20% lower than ABV so maybe that is what your chart is
calibrated to, weight, not volume.

More important, the potential alcohol scale is _exactly_ what it says
it is. It is only a crude measuurement of potential alcohol. There
in no way to measure density changes and categorically align them to
actual alcohol content with precision. The type and quantity of yeast
used, the temperature of fermentation and the storage conditions all
play into final alcohol content. PA does not consider dry extract
content either, most of which is acid and is variable to an easily
measurable degree. It can't. Wine can have a little acetic acid and
can have a whole lot, that affects the density too.

All that said, if you make the same wines the same way with the same
materials you can probably predict pretty well what your final alcohol
will be. I use those values as a rough guess of where things stand
and that is it. As I see it, this scale is useful to monitor
fermentation progress and very little else because then is a
marginally relative measurement. Even then the acids are changing to
a measurable degree and all my hydrometers measure is total density at
a given temperature.

As to why it doesn't go below zero, I'm pretty sure Baume calibrated
his scales with salt solutions so by definition they can't go below
zero. The final gravity is much affected by dry extract content so
where a dry wine will end up isn't just a matter of alcohol, it's the
acid content and other dissolved solids too. The best relatively
cheap way to measure alcohol is by distillation and hydrometry; that
way you are measuring relatively pure components. The best cheap way
to measure residual sugar is Clinitest tablets.

Physics is cool but I treat the PA scale like Myth Busters; I watch it
but I don't lend a lot of weight to it...

Joe

Joe Sallustio wrote:

On Nov 26, 2:46 pm, "Paul E. Lehmann"
wrote:
Joe Sallustio wrote:

Hi. Is there a special starter I should use
to
re-start this? Room temperature shouldn't
be an issue - it's being kept in my pantry
so it is always warm enough.

Steve's post already gave you great advice
and the correct value of
'potential alcohol' for 1.100SG. (My tables
came from NBS so I know
they are right.) The only thing I would
expand on is the amount of
time to give it to get going. Starters need
to get going really well
before you add them to the total volume. I
keep doubling the volume of the starter and
let it get back to fermenting strongly.

13% ABV for an apple wine might be a little
heavy duty; if this died at around 9 or 10 %
I
might be happy with that. I show that as
1.022 to 1.029 S.G.

bobdrob,
I show 1.115 as 19.3 % ABV; I have the book
at home that probably
takes them higher; I have spreadsheet I made
on
my work PC. I can email you the spreadsheet.

Joe

Joe, are you sure of that? I quick check on my
program shows 1.115 SG to be equivalent to
15.78 Brix and the PA to be 15.78

Hi Paul,
Yes, I'm sure to a rounding error. I have the
book now. Baume
(modulus 145) is what most people refer to as
'potential alcohol'. I show 34.3 brix =1.14985
S.G. =18.90 Baume 145 at 20C.

I really think the confusion comes from two
places.

One, alcohol concentrations can be measured by
volume (V/V or ABV) or
weight ABW) . Most refer to ABV now and don't
mention ABW. ABW is about 20% lower than ABV so
maybe that is what your chart is calibrated to,
weight, not volume.

More important, the potential alcohol scale is
_exactly_ what it says
it is. It is only a crude measuurement of
potential alcohol. There in no way to measure
density changes and categorically align them to
actual alcohol content with precision. The type
and quantity of yeast
used, the temperature of fermentation and the
storage conditions all
play into final alcohol content. PA does not
consider dry extract content either, most of
which is acid and is variable to an easily
measurable degree. It can't. Wine can have a
little acetic acid and can have a whole lot,
that affects the density too.

All that said, if you make the same wines the
same way with the same materials you can
probably predict pretty well what your final
alcohol
will be. I use those values as a rough guess of
where things stand
and that is it. As I see it, this scale is
useful to monitor fermentation progress and very
little else because then is a
marginally relative measurement. Even then the
acids are changing to a measurable degree and
all my hydrometers measure is total density at a
given temperature.

As to why it doesn't go below zero, I'm pretty
sure Baume calibrated his scales with salt
solutions so by definition they can't go below
zero. The final gravity is much affected by dry
extract content so where a dry wine will end up
isn't just a matter of alcohol, it's the
acid content and other dissolved solids too.
The best relatively cheap way to measure alcohol
is by distillation and hydrometry; that
way you are measuring relatively pure
components. The best cheap way to measure
residual sugar is Clinitest tablets.

Physics is cool but I treat the PA scale like
Myth Busters; I watch it
but I don't lend a lot of weight to it...

Joe

Just curious, what does your book say the PA and
SG equivalent to 22 Brix is?

Personally, I am not hung up on Alcohol. In fact
I very much dislike the high Brix Central Valley
California wines. I much more prefer the lower
alcohol Mid Atlantic wines. They go a lot better
with food. I guess that is why they are called
"old style" wines.

On Nov 27, 4:10 am, Joe Sallustio wrote:
On Nov 26, 2:46 pm, "Paul E. Lehmann" wrote:





Joe Sallustio wrote:

Hi. Is there a special starter I should use to
re-start this? Room temperature shouldn't be
an issue - it's being kept in my pantry so it
is always warm enough.

Steve's post already gave you great advice and
the correct value of
'potential alcohol' for 1.100SG. (My tables
came from NBS so I know
they are right.) The only thing I would expand
on is the amount of
time to give it to get going. Starters need to
get going really well
before you add them to the total volume. I
keep doubling the volume of the starter and let
it get back to fermenting strongly.

13% ABV for an apple wine might be a little
heavy duty; if this died at around 9 or 10 % I
might be happy with that. I show that as 1.022
to 1.029 S.G.

bobdrob,
I show 1.115 as 19.3 % ABV; I have the book at
home that probably
takes them higher; I have spreadsheet I made on
my work PC. I can email you the spreadsheet.

Joe

Joe, are you sure of that? I quick check on my
program shows 1.115 SG to be equivalent to 15.78
Brix and the PA to be 15.78

Hi Paul,
Yes, I'm sure to a rounding error. I have the book now. Baume
(modulus 145) is what most people refer to as 'potential alcohol'. I
show 34.3 brix =1.14985 S.G. =18.90 Baume 145 at 20C.


Okay, that explains it - Joe, I think you're missing a "1" in the
second decimal point, so we're comparing sg of 1.11 against that of
1.15, which would account for the large discrepancy in the calculated
alcohol value.

Pp

On Nov 27, 2:30 am, jim wrote:
Hi Gene, alcohol is definitely less dense than water, but if a wine at
1.000 is not quite dry, why do they calibrate 1.000 with 0PA? Do you
see why I think it is confusing?

Jim


Because when you have a wine with sg of 1.000, you're talking about a
final gravity reading, after fermentation. The PA table, on the other
hand talks about the starting gravity of the must. The PA tables are
usually calibrated for a water-sugar solution and 1.000 is the sg
point of water, so "must" of 1.000 by definition contains no sugar so
it has PA of 0%.

Pp

My understanding is the SG 1.000 is calibrated with distilled water at
20 degC (68 degF).

Zero PA (0PA) is a stable reference point, though it doesn't reflect the
true zero PA density of grape must. About 5-10 percent of the total
soluble solids in the grape must are from non-fermentable sugars,
organic acids, organic acid salts, nitrogen-containing compounds,
tannins, pectins and mineral salts.

These other soluble solids are responsible for a lot of the uncertainty
in PA calculation from must SG. Alcohol evaporation during fermentation
is the other significant variable making PA an inexact predictor of
final alcohol content.

I found the following reference about grape maturity useful for getting
a good picture of the grape growing practices and analyses on winemaking
results.
http://winegrapes.tamu.edu/grow/maturity.pdf

One topic they discuss is potential alcohol.

Gene



jim wrote:
Hi Gene, alcohol is definitely less dense than water, but if a wine at
1.000 is not quite dry, why do they calibrate 1.000 with 0PA? Do you
see why I think it is confusing?

Jim

On Nov 27, 9:34 am, gene wrote:
The final SG of a wine fermented to dryness has to account for the fact
that the alcohol in the wine is less dense than water. That's why the
dry wine has an SG less than 1.000. A wine at SG 1.000 is not quite dry.

Gene

jim wrote:
Heh sorry to miss you out. Thanks for the info.
I understand that PA starts with the potential. What I am getting at
is that SG and PA are given a common correlation as being discussed in
this thread. Yet, SG works on total movement (from initial to final
SG). So, what is the difference between a wine with PA of 15 that
finishes at SG 1.000 and a wine with a PA of 15 which finishes at
0.990?
That still *weirds me out* Many thanks and I hope this isn't too off
topic.
Jim
On Nov 27, 1:04 am, pp wrote:
Why is everybody calling me Joe these days? :-p
As for the 0.990 vs 1.000 difference, basically, you can think about
it as the table being designed so that instead of using the difference
between the starting and final sg points, you're only using the
starting point. In other words, the table is built with the assumption
that your wine ferments completely to dryness (because that's what PA
means) and gives you the PA values with that assumption.
Pp
On Nov 26, 1:37 pm, jim wrote:
I use this table:http://www.brsquared.org/wine/CalcInfo/HydSugAl.htm
which backs paul and joe's comments.
I have to admit though, I never quite understood how this can be if
0PA is 1.000 and I usually ferment down to around 0.990
Jim
On Nov 26, 8:36 pm, pp wrote:
On Nov 26, 11:46 am, "Paul E. Lehmann" wrote:
Joe Sallustio wrote:
Hi. Is there a special starter I should use to
re-start this? Room temperature shouldn't be
an issue - it's being kept in my pantry so it
is always warm enough.
Steve's post already gave you great advice and
the correct value of
'potential alcohol' for 1.100SG. (My tables
came from NBS so I know
they are right.) The only thing I would expand
on is the amount of
time to give it to get going. Starters need to
get going really well
before you add them to the total volume. I
keep doubling the volume of the starter and let
it get back to fermenting strongly.
13% ABV for an apple wine might be a little
heavy duty; if this died at around 9 or 10 % I
might be happy with that. I show that as 1.022
to 1.029 S.G.
bobdrob,
I show 1.115 as 19.3 % ABV; I have the book at
home that probably
takes them higher; I have spreadsheet I made on
my work PC. I can email you the spreadsheet.
Joe
Joe, are you sure of that? I quick check on my
program shows 1.115 SG to be equivalent to 15.78
Brix and the PA to be 15.78- Hide quoted text -
- Show quoted text -
Same here - don't have the tables on me but last couple of years we
got some Zin and Petite Sirah grapes that were over 1.130. I remember
checking the PA on those and even that was definitely under 20% - not
that we fermented them that way!
Pp- Hide quoted text -
- Show quoted text -

"jim" wrote in message
...
Hi Gene, alcohol is definitely less dense than water, but if a wine at
1.000 is not quite dry, why do they calibrate 1.000 with 0PA? Do you
see why I think it is confusing?

Jim

The scales on a hydrometer are like a snapshot. A picture of a
moment frozen in time. That picture is of a prepitch must with
no alcohol in it. Once alcohol enters the picture, the claibration
on the hydrometer is no longer valid. HTH

Frederick

On Nov 28, 12:00 pm, "frederick ploegman"
wrote:
"jim" wrote in message

...

Hi Gene, alcohol is definitely less dense than water, but if a wine at
1.000 is not quite dry, why do they calibrate 1.000 with 0PA? Do you
see why I think it is confusing?

Jim

The scales on a hydrometer are like a snapshot. A picture of a
moment frozen in time. That picture is of a prepitch must with
no alcohol in it. Once alcohol enters the picture, the claibration
on the hydrometer is no longer valid. HTH

Frederick

Now that makes it all coherent for me, thanks Frederick!

jim wrote:
On Nov 28, 12:00 pm, "frederick ploegman"
wrote:
"jim" wrote in message

...

Hi Gene, alcohol is definitely less dense than water, but if a wine at
1.000 is not quite dry, why do they calibrate 1.000 with 0PA? Do you
see why I think it is confusing?
Jim
The scales on a hydrometer are like a snapshot. A picture of a
moment frozen in time. That picture is of a prepitch must with
no alcohol in it. Once alcohol enters the picture, the claibration
on the hydrometer is no longer valid. HTH

Frederick

Now that makes it all coherent for me, thanks Frederick!

Are you sure about that, Frederick?

My understanding is that alcohol doesn't affect the Specific Gravity
accuracy, but it does affect the correlation to "potential alcohol" and
"degrees Brix". The more alcohol, the bigger the skew error.

I'm aware of only three significant factors that cause errors in
specific gravity measurement of wine with a properly calibrated hydrometer.

First, bubbles in the solution cause buoyancy errors (that's why we spin
the hydrometer, to knock bubbles off of it). Second, suspended solids
(floating grape skins, etc.) which, if touching the hydrometer, cause
buoyancy errors. Third is temperature of the juice, for which we have
SG correction tables.

Am I missing something here?

Gene

"gene" wrote in message
t...
jim wrote:
On Nov 28, 12:00 pm, "frederick ploegman"
wrote:
"jim" wrote in message

...

Hi Gene, alcohol is definitely less dense than water, but if a wine at
1.000 is not quite dry, why do they calibrate 1.000 with 0PA? Do you
see why I think it is confusing?
Jim
The scales on a hydrometer are like a snapshot. A picture of a
moment frozen in time. That picture is of a prepitch must with
no alcohol in it. Once alcohol enters the picture, the claibration
on the hydrometer is no longer valid. HTH

Frederick

Now that makes it all coherent for me, thanks Frederick!

Are you sure about that, Frederick?

My understanding is that alcohol doesn't affect the Specific Gravity
accuracy, but it does affect the correlation to "potential alcohol" and
"degrees Brix". The more alcohol, the bigger the skew error.


snip

Yup - that's what I meant. Jim's question was about the relationship
between SG and PA and alcohol definitely "skews" that up. ;o)

Frederick

Apples and pears contain sorbitol which give them nonfermentable
gravity. The effect you describe does occasionally occur with some
varietys of pears. Apples the effect is always present but is
ususually quite low.
Stuck ferments on apple is sometimes due to zinc deficiency Years ago
I used to add twenty grams of zinc sulphate and five grams of thiamine
to twenty five thousand litres of ferment this was enough in most
cases to unstick a stuck ferment.

Bob M
www.molab.co.nz

Hi. It's been a while since I participated in this discussion - the
old adage of busy life being my crutch. Thanks to the theads I did
make a starter to try and re-start this batch. I was successful and
this weekend I have started working on getting the batch clear and
ready for bottling. It's been a fun experiment though not quite the
taste I was hoping for (at least the test glass I couldn't resist
trying the other night), I'm sure this will improve with age.

While I haven't taken the time to write in, it's been great fun to
follow the threads here and it's done a lot to keep my interest piqued
for wine-making adventures.

Cheers and merry Christmas.

Chris
Charlottetown, PEI, Canada