Winemaking (rec.crafts.winemaking) Discussion of the process, recipes, tips, techniques and general exchange of lore on the process, methods and history of wine making. Includes traditional grape wines, sparkling wines & champagnes.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1 (permalink)   Report Post  
Galileo
 
Posts: n/a
Default Q: Gewurztraminer Numbers

Hello All,

I just defrosted a pail of Gewurz juice from Columbia Gorge, WA and
here are the numbers

Brix, 22.8
TA, 5.2 g/l
pH 3.37

Unfortunately due to my poor planning I could not get Cote De Blanc
for this and I am using Lavlin 1116 instead.

Assuming this ferments to 0.990, this is a PA of something like 13.5%

I would like to make about half dry and half off-dry and I am a little
concerned about the alcohol level. Any suggestions on how to proceed?

Also, from my fruit wine making experience I always sulfite when
making the starter and pitch 12-24 hours later. Is this initial dose
of sulfite really necessary for healthy fruit? Is there anything
wrong with waiting to add it until after alcoholic fermentation? I
recall reading that sulfites prevent the yeast from metabolizing
acetaldehyde to alcohol. Since acetaldehyde is a fault would it not
be better to add the sulfites once the fermentation is complete?

Thanks for the advice,
-Galileo
  #2 (permalink)   Report Post  
Aaron Puhala
 
Posts: n/a
Default Gewurztraminer Numbers

No issue with the brix, 22.8 Brix should get you around 12.5% alcohol. The
acid level, however, is too low for a white wine. I suggest double-checking
the acid and then adding tartaric acid to get somewhere between 7 and 8 g/L.
As far as sulfite is concerned, many juice sources add some sulfite to the
juice already so you may not need to add any. A dose of 30-60ppm is "wise"
in my opinion for whites. Of course, you still should adjust to 30-40ppm
prior to bottling. I wouldn't be concerned about acetaldehyde, just follow
good white winemaking practices. Full containers and minimal air contact
after your first racking. Regarding, 1116 yeast, this is a very good clean
fermenting yeast for whites.

CHEERS!

Aaron

"Galileo" > wrote in message
om...
> Hello All,
>
> I just defrosted a pail of Gewurz juice from Columbia Gorge, WA and
> here are the numbers
>
> Brix, 22.8
> TA, 5.2 g/l
> pH 3.37
>
> Unfortunately due to my poor planning I could not get Cote De Blanc
> for this and I am using Lavlin 1116 instead.
>
> Assuming this ferments to 0.990, this is a PA of something like 13.5%
>
> I would like to make about half dry and half off-dry and I am a little
> concerned about the alcohol level. Any suggestions on how to proceed?
>
> Also, from my fruit wine making experience I always sulfite when
> making the starter and pitch 12-24 hours later. Is this initial dose
> of sulfite really necessary for healthy fruit? Is there anything
> wrong with waiting to add it until after alcoholic fermentation? I
> recall reading that sulfites prevent the yeast from metabolizing
> acetaldehyde to alcohol. Since acetaldehyde is a fault would it not
> be better to add the sulfites once the fermentation is complete?
>
> Thanks for the advice,
> -Galileo



  #3 (permalink)   Report Post  
Aaron Puhala
 
Posts: n/a
Default Gewurztraminer Numbers

No issue with the brix, 22.8 Brix should get you around 12.5% alcohol. The
acid level, however, is too low for a white wine. I suggest double-checking
the acid and then adding tartaric acid to get somewhere between 7 and 8 g/L.
As far as sulfite is concerned, many juice sources add some sulfite to the
juice already so you may not need to add any. A dose of 30-60ppm is "wise"
in my opinion for whites. Of course, you still should adjust to 30-40ppm
prior to bottling. I wouldn't be concerned about acetaldehyde, just follow
good white winemaking practices. Full containers and minimal air contact
after your first racking. Regarding, 1116 yeast, this is a very good clean
fermenting yeast for whites.

CHEERS!

Aaron


"Galileo" > wrote in message
om...
> Hello All,
>
> I just defrosted a pail of Gewurz juice from Columbia Gorge, WA and
> here are the numbers
>
> Brix, 22.8
> TA, 5.2 g/l
> pH 3.37
>
> Unfortunately due to my poor planning I could not get Cote De Blanc
> for this and I am using Lavlin 1116 instead.
>
> Assuming this ferments to 0.990, this is a PA of something like 13.5%
>
> I would like to make about half dry and half off-dry and I am a little
> concerned about the alcohol level. Any suggestions on how to proceed?
>
> Also, from my fruit wine making experience I always sulfite when
> making the starter and pitch 12-24 hours later. Is this initial dose
> of sulfite really necessary for healthy fruit? Is there anything
> wrong with waiting to add it until after alcoholic fermentation? I
> recall reading that sulfites prevent the yeast from metabolizing
> acetaldehyde to alcohol. Since acetaldehyde is a fault would it not
> be better to add the sulfites once the fermentation is complete?
>
> Thanks for the advice,
> -Galileo



  #4 (permalink)   Report Post  
Lum
 
Posts: n/a
Default Gewurztraminer Numbers


"Galileo" > wrote in message
om...
> Hello All,
>
> I just defrosted a pail of Gewurz juice from Columbia Gorge, WA and
> here are the numbers
>
> Brix, 22.8
> TA, 5.2 g/l
> pH 3.37
>
> Unfortunately due to my poor planning I could not get Cote De Blanc
> for this and I am using Lavlin 1116 instead.
>
> Assuming this ferments to 0.990, this is a PA of something like 13.5%
>
> I would like to make about half dry and half off-dry and I am a little
> concerned about the alcohol level. Any suggestions on how to proceed?
>
> Also, from my fruit wine making experience I always sulfite when
> making the starter and pitch 12-24 hours later.


Reasonable amounts of sulfur dioxide will not kill native yeast. It only
curtails yeast activity for a few hours. On the other hand, commercial wine
yeast are practically unaffected by reasonable amounts of sulfur dioxide.
So, contrary to much home winemaking literature, commercial wine yeast
should be added immediately following the sulfur dioxide addition. The
inoculated yeast cells can then multiply quickly while the native yeast is
stunned, and the inoculated yeast will dominate the native yeast throughout
the fermentation period.

> Is this initial dose
> of sulfite really necessary for healthy fruit? Is there anything
> wrong with waiting to add it until after alcoholic fermentation? I
> recall reading that sulfites prevent the yeast from metabolizing
> acetaldehyde to alcohol. Since acetaldehyde is a fault would it not
> be better to add the sulfites once the fermentation is complete?


Sulfur dioxide is often not necessary for healthy fruit. But, by the time
wine is bottled, considerable oxidation has taken place and a significant
amount of acetaldehyde has accumulated. So, the additional amount of
acetaldehyde produced by normal amounts of sulfur dioxide added prior to
fermentation would be negligible.

Regards,
lum



  #5 (permalink)   Report Post  
Galileo
 
Posts: n/a
Default Gewurztraminer Numbers

"Aaron Puhala" > wrote in message >...
> No issue with the brix, 22.8 Brix should get you around 12.5% alcohol. The
> acid level, however, is too low for a white wine. I suggest double-checking
> the acid and then adding tartaric acid to get somewhere between 7 and 8 g/L.
> As far as sulfite is concerned, many juice sources add some sulfite to the
> juice already so you may not need to add any. A dose of 30-60ppm is "wise"
> in my opinion for whites. Of course, you still should adjust to 30-40ppm
> prior to bottling. I wouldn't be concerned about acetaldehyde, just follow
> good white winemaking practices. Full containers and minimal air contact
> after your first racking. Regarding, 1116 yeast, this is a very good clean
> fermenting yeast for whites.
>
> CHEERS!
>
> Aaron
>


Thanks for the advice. I added 0.8g/l Tartaric to bring the TA up to
6g/l and pitched last night, now I am crossing my fingers, hoping the
temperature stays in the low 60's for the next week or so.

I thought I understood Brix, but maybe not. The starting SG is 1.097
which is a PA of about 12.7% alcohol. And, so far, my final SG has
usually been below 1.00, usually about 0.990. Wouldn't this be a
final alcohol level of about 13.7% ?

Thanks,
Galileo


  #6 (permalink)   Report Post  
Galileo
 
Posts: n/a
Default Gewurztraminer Numbers

"Lum" > wrote in message >...
> "Galileo" > wrote in message
> om...
> > Hello All,
> >
> > I just defrosted a pail of Gewurz juice from Columbia Gorge, WA and
> > here are the numbers
> >
> > Brix, 22.8
> > TA, 5.2 g/l
> > pH 3.37
> >
> > Unfortunately due to my poor planning I could not get Cote De Blanc
> > for this and I am using Lavlin 1116 instead.
> >
> > Assuming this ferments to 0.990, this is a PA of something like 13.5%
> >
> > I would like to make about half dry and half off-dry and I am a little
> > concerned about the alcohol level. Any suggestions on how to proceed?
> >
> > Also, from my fruit wine making experience I always sulfite when
> > making the starter and pitch 12-24 hours later.

>
> Reasonable amounts of sulfur dioxide will not kill native yeast. It only
> curtails yeast activity for a few hours. On the other hand, commercial wine
> yeast are practically unaffected by reasonable amounts of sulfur dioxide.
> So, contrary to much home winemaking literature, commercial wine yeast
> should be added immediately following the sulfur dioxide addition. The
> inoculated yeast cells can then multiply quickly while the native yeast is
> stunned, and the inoculated yeast will dominate the native yeast throughout
> the fermentation period.


This is interesting. I will keep this in mind for future batches.

>
> > Is this initial dose
> > of sulfite really necessary for healthy fruit? Is there anything
> > wrong with waiting to add it until after alcoholic fermentation? I
> > recall reading that sulfites prevent the yeast from metabolizing
> > acetaldehyde to alcohol. Since acetaldehyde is a fault would it not
> > be better to add the sulfites once the fermentation is complete?

>
> Sulfur dioxide is often not necessary for healthy fruit. But, by the time
> wine is bottled, considerable oxidation has taken place and a significant
> amount of acetaldehyde has accumulated. So, the additional amount of
> acetaldehyde produced by normal amounts of sulfur dioxide added prior to
> fermentation would be negligible.


This is also interesting. It is always good to hear a reality check
with respect to the dominant behavior of various practices.
Basically, I just need to keep the sulfite levels at about 50ppm,
adjust acid, and let the yeast do their thing.

> Regards,
> lum


Thanks for taking the time to comment.

-Galileo
  #7 (permalink)   Report Post  
Aaron Puhala
 
Posts: n/a
Default Gewurztraminer Numbers

Regarding Brix: Brix is a measure of dissolved solids in your juice, namely
sugar. Theoretically, yeast will convert sugar to ethanol at a rate of
about 55% so you can estimate the alcohol content of your finished DRY wine
by muliplying Brix X 0.55, in your case 22.8 Brix X 0.55 = 12.5%Alcohol.

I would also suggest that you bump up your acid a bit more (perhaps others
would care to give their advice as well). I have found that less than 0.70
g/L gives a fairly flat white wine after a couple years in the bottle. This
can be a matter of taste, however, as I prefer crisp dry white wines,
especially after a couple years of "vacation" in the bottle. I believe you
said you were going to finish some of this slightly sweet. If this is the
case, I strongly suggest a bit higher acid as you will need more to balance
the residual sugar.

Good luck with your wine!

CHEERS!

Aaron

"Galileo" > wrote in message
om...
> "Aaron Puhala" > wrote in message

>...
> > No issue with the brix, 22.8 Brix should get you around 12.5% alcohol.

The
> > acid level, however, is too low for a white wine. I suggest

double-checking
> > the acid and then adding tartaric acid to get somewhere between 7 and 8

g/L.
> > As far as sulfite is concerned, many juice sources add some sulfite to

the
> > juice already so you may not need to add any. A dose of 30-60ppm is

"wise"
> > in my opinion for whites. Of course, you still should adjust to

30-40ppm
> > prior to bottling. I wouldn't be concerned about acetaldehyde, just

follow
> > good white winemaking practices. Full containers and minimal air

contact
> > after your first racking. Regarding, 1116 yeast, this is a very good

clean
> > fermenting yeast for whites.
> >
> > CHEERS!
> >
> > Aaron
> >

>
> Thanks for the advice. I added 0.8g/l Tartaric to bring the TA up to
> 6g/l and pitched last night, now I am crossing my fingers, hoping the
> temperature stays in the low 60's for the next week or so.
>
> I thought I understood Brix, but maybe not. The starting SG is 1.097
> which is a PA of about 12.7% alcohol. And, so far, my final SG has
> usually been below 1.00, usually about 0.990. Wouldn't this be a
> final alcohol level of about 13.7% ?
>
> Thanks,
> Galileo



  #9 (permalink)   Report Post  
Galileo
 
Posts: n/a
Default Gewurztraminer Numbers

"Aaron Puhala" > wrote in message >. ..
> Regarding Brix: Brix is a measure of dissolved solids in your juice, namely
> sugar. Theoretically, yeast will convert sugar to ethanol at a rate of
> about 55% so you can estimate the alcohol content of your finished DRY wine
> by muliplying Brix X 0.55, in your case 22.8 Brix X 0.55 = 12.5%Alcohol.
>
> I would also suggest that you bump up your acid a bit more (perhaps others
> would care to give their advice as well). I have found that less than 0.70
> g/L gives a fairly flat white wine after a couple years in the bottle. This
> can be a matter of taste, however, as I prefer crisp dry white wines,
> especially after a couple years of "vacation" in the bottle. I believe you
> said you were going to finish some of this slightly sweet. If this is the
> case, I strongly suggest a bit higher acid as you will need more to balance
> the residual sugar.
>
> Good luck with your wine!
>
> CHEERS!
>
> Aaron


Thank for the info on PA, I was never sure weather or not the
hydrometer took into account the final SG of the wine being below that
of water.

I agree with your acid suggestions. Although the must is listed as
having an initial TA of 5.2 g/l, it tasted a little more sour than
that and I did not want to over do it. Is there anything wrong with
waiting until bottling time to adjust the acid on the dry and off-dry
portion separately?

Thanks,
-Chris.
  #10 (permalink)   Report Post  
Aaron Puhala
 
Posts: n/a
Default Gewurztraminer Numbers

Additions of acid are generally thought to be perceived as "better
integrated" if made before fermentation. I shoot for 7-8g/L TA in my whites
and I take measures to prevent malolactic fermentation. Selecting a
starting acid level can be much easier to do with a dry white wine than with
one that will be off-dry because you know ahead of time how much residual
sugar will be in the final product ...nearly none! An off-dry style will
undoubtedly require more acid than its dry counterpart to achieve good
balance but the exact level of acid depends on the overall aromatics,
extract and body of the wine with the sugar present. I would suggest
starting your off-dry Gewurztraminer with 0.5 g/L higher acid than the dry.
You can still "season to taste" prior to bottling but starting the acid a
bit higher will keep your post-fermentation acid addition to a minimum. I
shoot for a level that I perceive as just a bit too tart at bottling time,
which is how I got to the 7-8 g/L range. This mellows over time and
promotes very elegant aging.

Good luck and CHEERS!!

Aaron



"Galileo" > wrote in message
om...
> "Aaron Puhala" > wrote in message

>. ..
> > Regarding Brix: Brix is a measure of dissolved solids in your juice,

namely
> > sugar. Theoretically, yeast will convert sugar to ethanol at a rate of
> > about 55% so you can estimate the alcohol content of your finished DRY

wine
> > by muliplying Brix X 0.55, in your case 22.8 Brix X 0.55 = 12.5%Alcohol.
> >
> > I would also suggest that you bump up your acid a bit more (perhaps

others
> > would care to give their advice as well). I have found that less than

0.70
> > g/L gives a fairly flat white wine after a couple years in the bottle.

This
> > can be a matter of taste, however, as I prefer crisp dry white wines,
> > especially after a couple years of "vacation" in the bottle. I believe

you
> > said you were going to finish some of this slightly sweet. If this is

the
> > case, I strongly suggest a bit higher acid as you will need more to

balance
> > the residual sugar.
> >
> > Good luck with your wine!
> >
> > CHEERS!
> >
> > Aaron

>
> Thank for the info on PA, I was never sure weather or not the
> hydrometer took into account the final SG of the wine being below that
> of water.
>
> I agree with your acid suggestions. Although the must is listed as
> having an initial TA of 5.2 g/l, it tasted a little more sour than
> that and I did not want to over do it. Is there anything wrong with
> waiting until bottling time to adjust the acid on the dry and off-dry
> portion separately?
>
> Thanks,
> -Chris.





  #11 (permalink)   Report Post  
Ray
 
Posts: n/a
Default Gewurztraminer Numbers

I have to differ with you on the interpretation of potential alcohol. The
majority of tables of PA / SG give the PA assuming the SG drops to 1.000.
This is not dry. That is why negative numbers are given on hydrometers for
PA when the hydrometer goes below 1.000. If you just go by the beginning SG
you can have a 1-2.5 points error in your PA. The only table that I am
aware of that assumes fermentation to true dryness is that of Duncan and
Acton though I have been told that UC Davis also takes this into account.

Ray

"JEP" > wrote in message
om...
> (Galileo) wrote in message

. com>...
> >
> > I thought I understood Brix, but maybe not. The starting SG is 1.097
> > which is a PA of about 12.7% alcohol. And, so far, my final SG has
> > usually been below 1.00, usually about 0.990. Wouldn't this be a
> > final alcohol level of about 13.7% ?
> >
> > Thanks,
> > Galileo

>
> The hydrometer's PA reading prior to fermentation gives you an
> estimate of the alcohol if all of the sugars are consumed. So you will
> get approximately 12.7% alcohol when the final SG of the wine is down
> in the .992 - .995 range. If the fermentation stops and your final SG
> is higher, not all of the sugars were consumed (or there was a
> significant amount of other disolved solids in the must) and the
> alcohol content will be less than the original PA.
>
> Andy



  #12 (permalink)   Report Post  
Aaron Puhala
 
Posts: n/a
Default Gewurztraminer Numbers

Ray's assertion is correct. While simple conversions tend to work very well
over time for established operations,
Potential Alcohol calculation is by no means straightforward in the larger
sense. The conversion factor of 0.55 to calculate
Potential Alcohol from Brix is a pretty standard industry value and has
worked well for me in general. Strictly speaking, every
gram of sugar consumed by the yeast will liberate at most 0.511 grams of
ethanol. This means that the 22.8 Brix could yeild a potential 11.65 w/w%
Ethanol which is about 14.3 v/v%. To achieve this level of ethanol after
fermentation would
require absolutely complete extraction of all sugar, 100% yeast efficiency,
0% evaporative loss, and
yeast fermentation to 0.00% residual sugar. Needless to say, this is highly
unlikely so usefull "conversion factors"
like the 0.55 discussed have become commonplace. I believe a range of
conversion factors of 0.54 - 0.62
would cover the vast majority of observed results in the industry globally
resulting in a v/v% ethanol range of
12.3% to 14.1% depending on the vast array of variables that can affect
conversion, efficiency, and loss.

CHEERS TO ALL!!

Aaron

"Ray" > wrote in message
news
> I have to differ with you on the interpretation of potential alcohol. The
> majority of tables of PA / SG give the PA assuming the SG drops to 1.000.
> This is not dry. That is why negative numbers are given on hydrometers
for
> PA when the hydrometer goes below 1.000. If you just go by the beginning

SG
> you can have a 1-2.5 points error in your PA. The only table that I am
> aware of that assumes fermentation to true dryness is that of Duncan and
> Acton though I have been told that UC Davis also takes this into account.
>
> Ray
>
> "JEP" > wrote in message
> om...
> > (Galileo) wrote in message

> . com>...
> > >
> > > I thought I understood Brix, but maybe not. The starting SG is 1.097
> > > which is a PA of about 12.7% alcohol. And, so far, my final SG has
> > > usually been below 1.00, usually about 0.990. Wouldn't this be a
> > > final alcohol level of about 13.7% ?
> > >
> > > Thanks,
> > > Galileo

> >
> > The hydrometer's PA reading prior to fermentation gives you an
> > estimate of the alcohol if all of the sugars are consumed. So you will
> > get approximately 12.7% alcohol when the final SG of the wine is down
> > in the .992 - .995 range. If the fermentation stops and your final SG
> > is higher, not all of the sugars were consumed (or there was a
> > significant amount of other disolved solids in the must) and the
> > alcohol content will be less than the original PA.
> >
> > Andy

>
>



  #13 (permalink)   Report Post  
Glen Duff
 
Posts: n/a
Default Gewurztraminer Numbers

Galileo,

I agree with Aaron that you should bump up the acid a little higher.

I make Gewurztraminer and Riesling every year and like many I prefer
them just off-dry. My procedure is to ferment them dry, usually around
..992 SG and bottle them that way for the purpose of stability. I add a
little sugar syrup to taste at the time of drinking. A Gewurz with your
level of alcohol and a TA of 8 g/l would be nicely balanced especially
if you drink it slightly sweetened as it will help bring out that unique
and pleasant Gewurz flavour. I would personally avoid sorbate.

Good luck,

Glen Duff
--------------

Galileo wrote:

> "Lum" > wrote in message >...
>
>>"Galileo" > wrote in message
.com...
>>
>>>Hello All,
>>>
>>>I just defrosted a pail of Gewurz juice from Columbia Gorge, WA and
>>>here are the numbers
>>>
>>>Brix, 22.8
>>>TA, 5.2 g/l
>>>pH 3.37
>>>
>>>Unfortunately due to my poor planning I could not get Cote De Blanc
>>>for this and I am using Lavlin 1116 instead.
>>>
>>>Assuming this ferments to 0.990, this is a PA of something like 13.5%
>>>
>>>I would like to make about half dry and half off-dry and I am a little
>>>concerned about the alcohol level. Any suggestions on how to proceed?
>>>
>>>Also, from my fruit wine making experience I always sulfite when
>>>making the starter and pitch 12-24 hours later.
>>>

>>Reasonable amounts of sulfur dioxide will not kill native yeast. It only
>>curtails yeast activity for a few hours. On the other hand, commercial wine
>>yeast are practically unaffected by reasonable amounts of sulfur dioxide.
>>So, contrary to much home winemaking literature, commercial wine yeast
>>should be added immediately following the sulfur dioxide addition. The
>>inoculated yeast cells can then multiply quickly while the native yeast is
>>stunned, and the inoculated yeast will dominate the native yeast throughout
>>the fermentation period.
>>

>
> This is interesting. I will keep this in mind for future batches.
>
>
>> > Is this initial dose

>>
>>>of sulfite really necessary for healthy fruit? Is there anything
>>>wrong with waiting to add it until after alcoholic fermentation? I
>>>recall reading that sulfites prevent the yeast from metabolizing
>>>acetaldehyde to alcohol. Since acetaldehyde is a fault would it not
>>>be better to add the sulfites once the fermentation is complete?
>>>

>>Sulfur dioxide is often not necessary for healthy fruit. But, by the time
>>wine is bottled, considerable oxidation has taken place and a significant
>>amount of acetaldehyde has accumulated. So, the additional amount of
>>acetaldehyde produced by normal amounts of sulfur dioxide added prior to
>>fermentation would be negligible.
>>

>
> This is also interesting. It is always good to hear a reality check
> with respect to the dominant behavior of various practices.
> Basically, I just need to keep the sulfite levels at about 50ppm,
> adjust acid, and let the yeast do their thing.
>
>
>>Regards,
>>lum
>>

>
> Thanks for taking the time to comment.
>
> -Galileo
>


  #14 (permalink)   Report Post  
Galileo
 
Posts: n/a
Default Gewurztraminer Numbers

Glen Duff > wrote in message >...
> Galileo,
>
> I agree with Aaron that you should bump up the acid a little higher.
>
> I make Gewurztraminer and Riesling every year and like many I prefer
> them just off-dry. My procedure is to ferment them dry, usually around
> .992 SG and bottle them that way for the purpose of stability. I add a
> little sugar syrup to taste at the time of drinking. A Gewurz with your
> level of alcohol and a TA of 8 g/l would be nicely balanced especially
> if you drink it slightly sweetened as it will help bring out that unique
> and pleasant Gewurz flavour. I would personally avoid sorbate.
>
> Good luck,
>
> Glen Duff
> --------------
>


Thank you for your input. I am a little concerned with getting a
Gewurz that is too "bright" since I tend to favor less acidic whites.
The majority vote here is more acid though, so I am going to add 20
more grams tartaric to 7g/l and balance to taste at bottling time.

-Galileo
  #15 (permalink)   Report Post  
JEP
 
Posts: n/a
Default Gewurztraminer Numbers

"Aaron Puhala" > wrote in message >...
> Ray's assertion is correct.


I don't agree.

>While simple conversions tend to work very well
> over time for established operations,
> Potential Alcohol calculation is by no means straightforward in the larger
> sense.


Agreed.

> The conversion factor of 0.55 to calculate
> Potential Alcohol from Brix is a pretty standard industry value and has
> worked well for me in general. Strictly speaking, every
> gram of sugar consumed by the yeast will liberate at most 0.511 grams of
> ethanol.


Every gram of sugar converted to ethanol will result in .511 grams of
ethanol. More on this later.

This means that the 22.8 Brix could yeild a potential 11.65 w/w%
> Ethanol which is about 14.3 v/v%.


OK, I'll agree to this.

> To achieve this level of ethanol after
> fermentation would
> require absolutely complete extraction of all sugar, 100% yeast efficiency,
> 0% evaporative loss, and
> yeast fermentation to 0.00% residual sugar.


Don't forget the 5% of sugars that are used by the yeast but are not
converted to ethanol. My references say about 1% goes to new cells and
4% will end up as other compounds like pyruvate, acetate,
acetaldehyde, glycerol and lactate.

> Needless to say, this is highly
> unlikely so usefull "conversion factors"
> like the 0.55 discussed have become commonplace.


And because the hydrometer makers have to use one conversion factor.
They can not take these other variable into account because they vary
from fermentation to fermentation.

> I believe a range of
> conversion factors of 0.54 - 0.62
> would cover the vast majority of observed results in the industry globally
> resulting in a v/v% ethanol range of
> 12.3% to 14.1% depending on the vast array of variables that can affect
> conversion, efficiency, and loss.


I can't agree with the .62. Theoretically possible but not practically
possible. I think the .55 mark is more realistic in the home wine
making world and I believe it can be lower than that.

But back to Ray's comment, what ever the hydrometer uses as a
conversion rate (.55 is common because that is a common estimate and
probably pretty accurate for most circumstances) this assumes that the
wine has been fermented to dryness. That all of the sugars have been
consumed and the SG is somewhere in the .992-.994 range.

If the SG is still at the 1.000 range, either there is still some
sugar left or there was something other in solution besides sugar that
effected the original SG. Either way, you did not get as much alcohol
as anticipated, I would think around 1% ABV lower.

This is not to say that the hydrometer is a very accurate predictor of
alcohol, only that it's prediction is based on all sugars being
consumed and the final SG value being below 1.000.

Andy


  #16 (permalink)   Report Post  
Ray
 
Posts: n/a
Default Gewurztraminer Numbers

The scale that is on both of the different hydrometers that I have matches
very close to the tables given in such references as C.J.J. Berry in FIRST
STEPS IN WINEMAKING and on Jack Keller's site. Both of these state that
they assume fermentation goes to SG of 1.000 not dryness. This table can
also be derived from the more basic table presented in Duncan and Acton's
PROGRESSIVE WINEMAKING which is truly based on going to dryness by
correcting back to an SG of 1.000. Consequently, the PA table on the
hydrometers, at least the ones I have, are not based on fermenting to
dryness. If you have a credible reference that indicates otherwise, I would
like to see it. I really mean that as this is a topic of interest to me.

Ray

"JEP" > wrote in message
om...
> "Aaron Puhala" > wrote in message

>...
> > Ray's assertion is correct.

>
> I don't agree.
>
> >While simple conversions tend to work very well
> > over time for established operations,
> > Potential Alcohol calculation is by no means straightforward in the

larger
> > sense.

>
> Agreed.
>
> > The conversion factor of 0.55 to calculate
> > Potential Alcohol from Brix is a pretty standard industry value and has
> > worked well for me in general. Strictly speaking, every
> > gram of sugar consumed by the yeast will liberate at most 0.511 grams of
> > ethanol.

>
> Every gram of sugar converted to ethanol will result in .511 grams of
> ethanol. More on this later.
>
> This means that the 22.8 Brix could yeild a potential 11.65 w/w%
> > Ethanol which is about 14.3 v/v%.

>
> OK, I'll agree to this.
>
> > To achieve this level of ethanol after
> > fermentation would
> > require absolutely complete extraction of all sugar, 100% yeast

efficiency,
> > 0% evaporative loss, and
> > yeast fermentation to 0.00% residual sugar.

>
> Don't forget the 5% of sugars that are used by the yeast but are not
> converted to ethanol. My references say about 1% goes to new cells and
> 4% will end up as other compounds like pyruvate, acetate,
> acetaldehyde, glycerol and lactate.
>
> > Needless to say, this is highly
> > unlikely so usefull "conversion factors"
> > like the 0.55 discussed have become commonplace.

>
> And because the hydrometer makers have to use one conversion factor.
> They can not take these other variable into account because they vary
> from fermentation to fermentation.
>
> > I believe a range of
> > conversion factors of 0.54 - 0.62
> > would cover the vast majority of observed results in the industry

globally
> > resulting in a v/v% ethanol range of
> > 12.3% to 14.1% depending on the vast array of variables that can affect
> > conversion, efficiency, and loss.

>
> I can't agree with the .62. Theoretically possible but not practically
> possible. I think the .55 mark is more realistic in the home wine
> making world and I believe it can be lower than that.
>
> But back to Ray's comment, what ever the hydrometer uses as a
> conversion rate (.55 is common because that is a common estimate and
> probably pretty accurate for most circumstances) this assumes that the
> wine has been fermented to dryness. That all of the sugars have been
> consumed and the SG is somewhere in the .992-.994 range.
>
> If the SG is still at the 1.000 range, either there is still some
> sugar left or there was something other in solution besides sugar that
> effected the original SG. Either way, you did not get as much alcohol
> as anticipated, I would think around 1% ABV lower.
>
> This is not to say that the hydrometer is a very accurate predictor of
> alcohol, only that it's prediction is based on all sugars being
> consumed and the final SG value being below 1.000.
>
> Andy



  #17 (permalink)   Report Post  
JEP
 
Posts: n/a
Default Gewurztraminer Numbers

"Ray" > wrote in message om>...
> The scale that is on both of the different hydrometers that I have matches
> very close to the tables given in such references as C.J.J. Berry in FIRST
> STEPS IN WINEMAKING and on Jack Keller's site. Both of these state that
> they assume fermentation goes to SG of 1.000 not dryness. This table can
> also be derived from the more basic table presented in Duncan and Acton's
> PROGRESSIVE WINEMAKING which is truly based on going to dryness by
> correcting back to an SG of 1.000. Consequently, the PA table on the
> hydrometers, at least the ones I have, are not based on fermenting to
> dryness. If you have a credible reference that indicates otherwise, I would
> like to see it. I really mean that as this is a topic of interest to me.
>
> Ray
>


Hi Ray,

Sorry for taking so long, I've been a bit busy.

If you look at Jack's table on his hydrometer page, he shows the
potential alcohol for a Brix "if the must is fermented to SG=1.000".
This is not the same as what is shown on my hydrometers.

For instance, his table at brix 10 indicates a PA of 5.1%, my
hydrometer shows a PA of approx. 5.5%. I think maybe Jack is giving
you what the PA is if you go to 1.000, my hydrometer shows the PA if
you go to dryness. I not sure if all hydrometers use this scale, but
all of mine do.

Some of the following is using some general rules of thumb, but I
think it show why there is a discrepancy.

A Brix 10 must, if fermented to dryness would probably finish at
around SG=.997, subtracting from 1.000 would give us a .003
difference. Using the ROT of SG points divided by 4 = Brix, this would
give us around a .75 Brix difference or IOW, the 1.000 must would have
about .75% sugar remaining. Using a very standard .55 as a conversion
factor of Brix to PA we come up with .41 PA, which explains the
difference between Jacks PA (5.1) at a 1.000 end point and what is
presented on my hydrometer(5.5) at dryness.

As we go up down Jack's table, this doesn't appear to correlate. If we
only ferment to 1.000, as the original Brix goes up, we would be
leaving more and more sugar in the wine, but Jack's table appears to
be more of a simple .4 below my hydrometer's estimates.

My primary source of information is the course material for a UC Davis
course in wine making. It doesn't really go in hydrometer readings but
does talk about the conversion of sugar to alcohol and why a .55
conversion factor is a pretty good one if all sugars are consumed.

Of course this is only an academic exercise. There are way too many
other variables to predict the real alcohol content. It is nothing
more than a rough estimate no matter how you cut it.

BTW, could you check your hydrometers? Does brix 10 = PA 5.1 or 5.5 on
yours? What about brix 20? Mine shows a PA around 11%. It's easier if
you have the paper from a broken hydrometer because you can use a
straight edge. If you don't, holding the hydrometer at the edge of the
testing jar can help you judge across the scales.

Andy
Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
[TN] 2011 Navarro Dry Gewurztraminer Mark Lipton[_1_] Wine 1 17-02-2013 02:24 PM
[TN] 2000 Bott-Geyl Gewurztraminer Mark Lipton[_1_] Wine 2 16-12-2008 08:30 PM
[long] Gewurztraminer! Ed Rasimus Wine 1 17-07-2004 04:17 PM
Gewurztraminer Xyzsch Wine 7 25-04-2004 12:17 AM
Gewurztraminer Yeast and Other Factors Pavel314 Winemaking 2 05-11-2003 02:56 PM


All times are GMT +1. The time now is 01:04 AM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 FoodBanter.com.
The comments are property of their posters.
 

About Us

"It's about Food and drink"