Hello,
I bought some Zinfandel grapes from Brentwood CA. The grapes were at 24
brix but by the time I got over there and picked them they shot up to 26
brix. So I made wine anyways:

pH 3.82
TA 7
SG 1.110 or 16 brix (best I can read from my cheap hydrometer)
500 lbs of grapes
Pasteur Red yeast
Fermentaid K
Some Pectic Enzyme


I didn't add any acid since TA 7 is in the range of normal, but then I
changed my mind because the pH was high and I wanted to add MLF culture (a
mistake?). So I added 84 grams of tartaric to 50 gallons of must on the
second day of fermenting and added the MLF on the third day of fermenting
(this pressed out to 38 gallons of juice 8 days on the skins). So my
addition is about .44 grams per liter if you use total must volume or .58
grams per liter if you count the amount of juice I got out of the grapes
(which is the correct way to calculate it?) I did not measure the TA or pH
after addition since it was actively fermenting, but I measured it tonight
after heating it and swirling it around in a flask and now I have:

SG .996 (I think it is still fermenting slowly it was at 2 brix Saturday I
pressed the wine on Sunday)
pH 4
TA 7.
This seems odd that there can be so much acid but still have a high pH. I
used an Accumet pH meter from my lab at Stanford so the measurements should
be good. Although I got pH 3.88 then checked the calibration which was done
yesterday and when I recalibrated it I got PH 4.05. The wine smells good
and tastes good (for cloudy 10 day old stuff), but there is definitely some
heat from the alcohol and slight but not over powering tartness from the
acid. So I want to know what will happen to my high pH high alcohol wine?
Will the stuff go off easy? Should I risk adding acid to drop the pH and
take the risk of overly tart wine? Should I wait a couple of weeks and see
if it changes? Any advice would be appreciated.

Thank You for reading my long post.
-Alex

Alex wrote "I bought some Zinfandel grapes from Brentwood CA. The grapes
were at 24
brix but by the time I got over there and picked them they shot up to 26
brix. So I made wine anyways: pH 3.82, TA 7, SG 1.110 or 16 brix (best I
can read from my cheap hydrometer)

-Alex, did you do the tests to arrive at the above numbers? BTW 16 brix is
about SG 1.066.
You added 84 grams tartaric acid to 50 gallons of must (38gallons juice).
Like you say this works out to 0.58 grams per liter. The total acid in
your juice is now 7.58 grams per liter or 0.76%TA. This probably was not
enough acid addition to drop the pH much. I usually hang a pH probe in the
juice or wine. Calculate the maximum acid I dare to add. Then add acid up
to this amount with good mixing watching the pH drop.

The wine smells good....but there is definitely some heat from the alcohol
and slight but not over powering tartness from the acid.

-I'm not surprised at the alcoholic heat. But if you want to taste over
powering tartness from excess acid come to Kansas City and work with must
containing 0.9% TA.

Clyde Gill has a good laboratory method to determine how much acid addition
is required to drop pH to a desired value. He might be busy right now at
the winery so if he doesn't chime in I can post his method. Since you have
access to lab equipment you could try his method. If you want to get that
pH down to a reasonable number I think you will have to add tartaric acid
and then drop it out with a hard, cold conditioning later on.

Bill Frazier
Olathe, Kansas USA

Alex wrote "I bought some Zinfandel grapes from Brentwood CA. The grapes
were at 24
brix but by the time I got over there and picked them they shot up to 26
brix. So I made wine anyways: pH 3.82, TA 7, SG 1.110 or 16 brix (best I
can read from my cheap hydrometer)

-Alex, did you do the tests to arrive at the above numbers? BTW 16 brix is
about SG 1.066.
You added 84 grams tartaric acid to 50 gallons of must (38gallons juice).
Like you say this works out to 0.58 grams per liter. The total acid in
your juice is now 7.58 grams per liter or 0.76%TA. This probably was not
enough acid addition to drop the pH much. I usually hang a pH probe in the
juice or wine. Calculate the maximum acid I dare to add. Then add acid up
to this amount with good mixing watching the pH drop.

The wine smells good....but there is definitely some heat from the alcohol
and slight but not over powering tartness from the acid.

-I'm not surprised at the alcoholic heat. But if you want to taste over
powering tartness from excess acid come to Kansas City and work with must
containing 0.9% TA.

Clyde Gill has a good laboratory method to determine how much acid addition
is required to drop pH to a desired value. He might be busy right now at
the winery so if he doesn't chime in I can post his method. Since you have
access to lab equipment you could try his method. If you want to get that
pH down to a reasonable number I think you will have to add tartaric acid
and then drop it out with a hard, cold conditioning later on.

Bill Frazier
Olathe, Kansas USA

The 16 brix is a typo I meant 26.
-Alex


"William Frazier" > wrote in message
...
>
> Alex wrote "I bought some Zinfandel grapes from Brentwood CA. The grapes
> were at 24
> brix but by the time I got over there and picked them they shot up to 26
> brix. So I made wine anyways: pH 3.82, TA 7, SG 1.110 or 16 brix (best I
> can read from my cheap hydrometer)
>
> -Alex, did you do the tests to arrive at the above numbers? BTW 16 brix
is
> about SG 1.066.
> You added 84 grams tartaric acid to 50 gallons of must (38gallons juice).
> Like you say this works out to 0.58 grams per liter. The total acid in
> your juice is now 7.58 grams per liter or 0.76%TA. This probably was not
> enough acid addition to drop the pH much. I usually hang a pH probe in
the
> juice or wine. Calculate the maximum acid I dare to add. Then add acid
up
> to this amount with good mixing watching the pH drop.
>
> The wine smells good....but there is definitely some heat from the alcohol
> and slight but not over powering tartness from the acid.
>
> -I'm not surprised at the alcoholic heat. But if you want to taste over
> powering tartness from excess acid come to Kansas City and work with must
> containing 0.9% TA.
>
> Clyde Gill has a good laboratory method to determine how much acid
addition
> is required to drop pH to a desired value. He might be busy right now at
> the winery so if he doesn't chime in I can post his method. Since you
have
> access to lab equipment you could try his method. If you want to get that
> pH down to a reasonable number I think you will have to add tartaric acid
> and then drop it out with a hard, cold conditioning later on.
>
> Bill Frazier
> Olathe, Kansas USA
>
>

The 16 brix is a typo I meant 26.
-Alex


"William Frazier" > wrote in message
...
>
> Alex wrote "I bought some Zinfandel grapes from Brentwood CA. The grapes
> were at 24
> brix but by the time I got over there and picked them they shot up to 26
> brix. So I made wine anyways: pH 3.82, TA 7, SG 1.110 or 16 brix (best I
> can read from my cheap hydrometer)
>
> -Alex, did you do the tests to arrive at the above numbers? BTW 16 brix
is
> about SG 1.066.
> You added 84 grams tartaric acid to 50 gallons of must (38gallons juice).
> Like you say this works out to 0.58 grams per liter. The total acid in
> your juice is now 7.58 grams per liter or 0.76%TA. This probably was not
> enough acid addition to drop the pH much. I usually hang a pH probe in
the
> juice or wine. Calculate the maximum acid I dare to add. Then add acid
up
> to this amount with good mixing watching the pH drop.
>
> The wine smells good....but there is definitely some heat from the alcohol
> and slight but not over powering tartness from the acid.
>
> -I'm not surprised at the alcoholic heat. But if you want to taste over
> powering tartness from excess acid come to Kansas City and work with must
> containing 0.9% TA.
>
> Clyde Gill has a good laboratory method to determine how much acid
addition
> is required to drop pH to a desired value. He might be busy right now at
> the winery so if he doesn't chime in I can post his method. Since you
have
> access to lab equipment you could try his method. If you want to get that
> pH down to a reasonable number I think you will have to add tartaric acid
> and then drop it out with a hard, cold conditioning later on.
>
> Bill Frazier
> Olathe, Kansas USA
>
>

"William Frazier" > wrote in message
...
>
> Alex wrote "I bought some Zinfandel grapes from Brentwood CA. The grapes
> were at 24
> brix but by the time I got over there and picked them they shot up to 26
> brix. So I made wine anyways: pH 3.82, TA 7, SG 1.110 or 16 brix (best I
> can read from my cheap hydrometer)

Those numbers aren't really that bad. I recently read an article in a trade
magazine on picking at optimum ripeness. They were mainly talking about
Syrah, but this sounds good for Zinfandel too. One of the winemakers was
quoted as saying, "26 [Brix] is the new 24."

I'd recommend that you try to get the pH to ~3.6 or so _after_ ML and cold
stabilization. To do that, you need the ML to finish first. Then do bench
trials on the wine, adding 1g/liter, 2g/liter and 3g/liter to three samples.
Chill the wine to nearly freezing, until the bitartrate all drops out. This
can take as long as a couple of weeks. Decant the wines from the bitartrate
sediment, let them warm to cellar temperature and taste them, both with and
without food. See which you like best. Measure the pH if you like, but
it'll probably end up around 3.6 to 3.7 in the sample that tastes best to
you. Don't worry about the TA. That'll take care of itself.

Once you determine the correct addition (which could be somewhere in between
those numbers) scale the tartaric addition up for the whole batch. Get one
or two people who are better at math to check your numbers before you commit
the entire lot or you may end up back here asking how to do acid reduction!
You'll have to cold stabilize the entire lot, but you could actually wait
until after barrel aging to do that if you wish.

Tom S

"William Frazier" > wrote in message
...
>
> Alex wrote "I bought some Zinfandel grapes from Brentwood CA. The grapes
> were at 24
> brix but by the time I got over there and picked them they shot up to 26
> brix. So I made wine anyways: pH 3.82, TA 7, SG 1.110 or 16 brix (best I
> can read from my cheap hydrometer)

Those numbers aren't really that bad. I recently read an article in a trade
magazine on picking at optimum ripeness. They were mainly talking about
Syrah, but this sounds good for Zinfandel too. One of the winemakers was
quoted as saying, "26 [Brix] is the new 24."

I'd recommend that you try to get the pH to ~3.6 or so _after_ ML and cold
stabilization. To do that, you need the ML to finish first. Then do bench
trials on the wine, adding 1g/liter, 2g/liter and 3g/liter to three samples.
Chill the wine to nearly freezing, until the bitartrate all drops out. This
can take as long as a couple of weeks. Decant the wines from the bitartrate
sediment, let them warm to cellar temperature and taste them, both with and
without food. See which you like best. Measure the pH if you like, but
it'll probably end up around 3.6 to 3.7 in the sample that tastes best to
you. Don't worry about the TA. That'll take care of itself.

Once you determine the correct addition (which could be somewhere in between
those numbers) scale the tartaric addition up for the whole batch. Get one
or two people who are better at math to check your numbers before you commit
the entire lot or you may end up back here asking how to do acid reduction!
You'll have to cold stabilize the entire lot, but you could actually wait
until after barrel aging to do that if you wish.

Tom S

Tom,
Thanks for the advice... sometimes the obvious escapes me like testing small
batches. Would a 750ml bottle be large enough of a sample or should I use 1
gallon samples to treat and cold stabilize? How do people cold stabilize
their wines if they don't have a temperature controlled room? I do have
access to a 4 degree Celsius room at my lab and I could probably fit SS beer
kegs of wine in there without anyone getting upset with me, I only have 38
gallons, so I could do it in two kegs. How quickly do you have to transfer
the wine off the crystals before they dissolve? I would prefer to take the
kegs home and not make a mess in the lab if it won't hurt anything. What
happens if I do nothing?
Thanks,
Alex P


"Tom S" > wrote in message
. com...
>
> "William Frazier" > wrote in message
> ...
> >
> > Alex wrote "I bought some Zinfandel grapes from Brentwood CA. The
grapes
> > were at 24
> > brix but by the time I got over there and picked them they shot up to 26
> > brix. So I made wine anyways: pH 3.82, TA 7, SG 1.110 or 16 brix (best
I
> > can read from my cheap hydrometer)
>
> Those numbers aren't really that bad. I recently read an article in a
trade
> magazine on picking at optimum ripeness. They were mainly talking about
> Syrah, but this sounds good for Zinfandel too. One of the winemakers was
> quoted as saying, "26 [Brix] is the new 24."
>
> I'd recommend that you try to get the pH to ~3.6 or so _after_ ML and cold
> stabilization. To do that, you need the ML to finish first. Then do
bench
> trials on the wine, adding 1g/liter, 2g/liter and 3g/liter to three
samples.
> Chill the wine to nearly freezing, until the bitartrate all drops out.
This
> can take as long as a couple of weeks. Decant the wines from the
bitartrate
> sediment, let them warm to cellar temperature and taste them, both with an
d
> without food. See which you like best. Measure the pH if you like, but
> it'll probably end up around 3.6 to 3.7 in the sample that tastes best to
> you. Don't worry about the TA. That'll take care of itself.
>
> Once you determine the correct addition (which could be somewhere in
between
> those numbers) scale the tartaric addition up for the whole batch. Get
one
> or two people who are better at math to check your numbers before you
commit
> the entire lot or you may end up back here asking how to do acid
reduction!
> You'll have to cold stabilize the entire lot, but you could actually wait
> until after barrel aging to do that if you wish.
>
> Tom S
>
>

Tom,
Thanks for the advice... sometimes the obvious escapes me like testing small
batches. Would a 750ml bottle be large enough of a sample or should I use 1
gallon samples to treat and cold stabilize? How do people cold stabilize
their wines if they don't have a temperature controlled room? I do have
access to a 4 degree Celsius room at my lab and I could probably fit SS beer
kegs of wine in there without anyone getting upset with me, I only have 38
gallons, so I could do it in two kegs. How quickly do you have to transfer
the wine off the crystals before they dissolve? I would prefer to take the
kegs home and not make a mess in the lab if it won't hurt anything. What
happens if I do nothing?
Thanks,
Alex P


"Tom S" > wrote in message
. com...
>
> "William Frazier" > wrote in message
> ...
> >
> > Alex wrote "I bought some Zinfandel grapes from Brentwood CA. The
grapes
> > were at 24
> > brix but by the time I got over there and picked them they shot up to 26
> > brix. So I made wine anyways: pH 3.82, TA 7, SG 1.110 or 16 brix (best
I
> > can read from my cheap hydrometer)
>
> Those numbers aren't really that bad. I recently read an article in a
trade
> magazine on picking at optimum ripeness. They were mainly talking about
> Syrah, but this sounds good for Zinfandel too. One of the winemakers was
> quoted as saying, "26 [Brix] is the new 24."
>
> I'd recommend that you try to get the pH to ~3.6 or so _after_ ML and cold
> stabilization. To do that, you need the ML to finish first. Then do
bench
> trials on the wine, adding 1g/liter, 2g/liter and 3g/liter to three
samples.
> Chill the wine to nearly freezing, until the bitartrate all drops out.
This
> can take as long as a couple of weeks. Decant the wines from the
bitartrate
> sediment, let them warm to cellar temperature and taste them, both with an
d
> without food. See which you like best. Measure the pH if you like, but
> it'll probably end up around 3.6 to 3.7 in the sample that tastes best to
> you. Don't worry about the TA. That'll take care of itself.
>
> Once you determine the correct addition (which could be somewhere in
between
> those numbers) scale the tartaric addition up for the whole batch. Get
one
> or two people who are better at math to check your numbers before you
commit
> the entire lot or you may end up back here asking how to do acid
reduction!
> You'll have to cold stabilize the entire lot, but you could actually wait
> until after barrel aging to do that if you wish.
>
> Tom S
>
>

Hi Alex,
That pH seems awful high for a TA in the range you are talking. That
sounds like a good Fisher Scientific or Corning pH meter, but are you
calibrating it right before the measurement and are you degassing the
sample? If so are you sure of the normality of your NAOH? If it
tastes tart the TA seems right...

I take the sample to boiling for an instant prior to reading. CO2 can
make the pH seem falsely high.

The right way to do it is to measure out at least 50 ml of sample,
degas, add distilled water back to 50 ml if necessary, cal the meter,
measure pH and titrate acid.

Joe

Hi Alex,
That pH seems awful high for a TA in the range you are talking. That
sounds like a good Fisher Scientific or Corning pH meter, but are you
calibrating it right before the measurement and are you degassing the
sample? If so are you sure of the normality of your NAOH? If it
tastes tart the TA seems right...

I take the sample to boiling for an instant prior to reading. CO2 can
make the pH seem falsely high.

The right way to do it is to measure out at least 50 ml of sample,
degas, add distilled water back to 50 ml if necessary, cal the meter,
measure pH and titrate acid.

Joe

"Alex" > wrote in message
...
> Tom,
> Thanks for the advice... sometimes the obvious escapes me like testing
small
> batches. Would a 750ml bottle be large enough of a sample or should I use
1
> gallon samples to treat and cold stabilize?

750ml is plenty.

How do people cold stabilize
> their wines if they don't have a temperature controlled room?

At home I use a chest type freezer with an external temperature controller.
I can fit two 15 gallon kegs in it at a time.

I do have
> access to a 4 degree Celsius room at my lab and I could probably fit SS
beer
> kegs of wine in there without anyone getting upset with me, I only have
38
> gallons, so I could do it in two kegs. How quickly do you have to
transfer
> the wine off the crystals before they dissolve? I would prefer to take
the
> kegs home and not make a mess in the lab if it won't hurt anything.

At 4°C it might take quite awhile (~ a month) for the bitartrate to
precipitate. Once it does, however, it tends not to redissolve too easily.
The reason is that it has lost the heat of crystalization. Besides, on the
trip home it won't go from 4°C to room temp very quickly. You should have
plenty of time unless you live a _long_ way from work.

What
> happens if I do nothing?

The wine will perhaps drop out the excess bitartrate all by itself in
bottle - but that can take years, depending on your cellar temperature.

Tom S

William Frazier wrote "Clyde Gill has a good laboratory method to determine
how much acid addition is required to drop pH to a desired value. He might
be busy right now at the winery so if he doesn't chime in I can post his
method."

Here's Clyde's method. Since your wine is fermenting it probably won't be
possible to do this until it's dry so CO2 doesn't interfer with the result.
I think Clyde uses this method for juice before fermentation.

Make a tartaric acid solution
(Dissolve 2.0 grams t.acid in enough distilled water to make 200 ml. The
solution contains 0.01 gram per ml)
Measure out a specific volume of juice or wine (Example 50 ml)
Put a pH probe in the juice or wine. Add the t. acid solution to the sample
until the pH drops to the desired level (Clyde says pH 4.5 is ideal for
juice that will make a red wine)
Calculate how much t. acid is needed for one gallon (3785 ml) juice or wine
(volume of t.acid solution used x 0.01 = grams t. acid required for the 50ml
sample)
(3785ml / 50 ml = 75.7 x grams t. acid required for the sample)
Multiply the result by the number of gallons of juice or wine you want to
treat

I would still stick a pH probe in the bulk juice or wine and add tartaric
acid slowly with good mixing.

Bill Frazier
Olathe, Kansas USA

Joe,
I did calibrate the meter just before use and I made up the .2 M NaOH
from a 5 M stock that is only a few weeks old. I am not so certain I
properly degassed the wine though. I had it in a 50 ml conical tube and
microwaved it until it was hot (not yet boiling) and I saw a bunch of
bubbles forming on the side of the tube. I then put 15 ml in a flask and
swirled it around for a while and waited for it to cool off before I checked
the pH and titrated the acid. I will definitely re check it, but if nothing
terrible will happen to the wine in the short term I will wait for
fermentation and ML to stop completely. There is still an occasional bubble
coming out of the air lock.

In case I get anxious or for next time , can the wine be degassed properly
by putting it under a vacuum or bubbling nitrogen through it? I have both
of these readily available and maybe it would be more certain than just
heating it up?
-Alex
"Joe Sallustio" > wrote in message
om...
> Hi Alex,
> That pH seems awful high for a TA in the range you are talking. That
> sounds like a good Fisher Scientific or Corning pH meter, but are you
> calibrating it right before the measurement and are you degassing the
> sample? If so are you sure of the normality of your NAOH? If it
> tastes tart the TA seems right...
>
> I take the sample to boiling for an instant prior to reading. CO2 can
> make the pH seem falsely high.
>
> The right way to do it is to measure out at least 50 ml of sample,
> degas, add distilled water back to 50 ml if necessary, cal the meter,
> measure pH and titrate acid.
>
> Joe

Alex,
Your process was pretty good, the only thing I would do differently is
make sure I still had 50 ml after the heating. Add distilled water if
necessary, then pull the sample.

Vacuum degassing or purging with nitrogen may work, but I'm not a
chemist so I can't say with certainty. Margalit suggests the heating
process you used, but uses a 100 ml sample size. His book Winery
Technology is great and under $30 US. Mine is pretty worn out.

You seem to have a lot of potassium in that must. The ratio of malic
falls and tartaric rises (since it does not fall) in mature grapes.
Adding tartaric as Tom and Bill suggest will pull the potassium out
and swing the pH better than malic so I would do that too. You really
do want to cold stabilize. 25 F is faster than 40 F, but winter is
coming and that could be an option too.

I'm not as experienced as Tom and still measure and use TA. It's
easier to understand and manipulate for me since the relationship is
linear, not a log function like pH.

It's also easier for me to correlate taste to TA than pH, I have never
had a dry red with a TA over 6g/l that I thought was balanced. It's
always too tart for me. OTOH I've had the pH all over the place (from
3.45 to 3.85) on wines I like with a TA under 6 and that's a big
difference (to me).

Taste is everything though, trust your taste over optimal values in a
book. The author is not drinking your wine...

)

Joe

"Alex" > wrote in message >...
> Joe,
> I did calibrate the meter just before use and I made up the .2 M NaOH
> from a 5 M stock that is only a few weeks old. I am not so certain I
> properly degassed the wine though. I had it in a 50 ml conical tube and
> microwaved it until it was hot (not yet boiling) and I saw a bunch of
> bubbles forming on the side of the tube. I then put 15 ml in a flask and
> swirled it around for a while and waited for it to cool off before I checked
> the pH and titrated the acid. I will definitely re check it, but if nothing
> terrible will happen to the wine in the short term I will wait for
> fermentation and ML to stop completely. There is still an occasional bubble
> coming out of the air lock.
>
> In case I get anxious or for next time , can the wine be degassed properly
> by putting it under a vacuum or bubbling nitrogen through it? I have both
> of these readily available and maybe it would be more certain than just
> heating it up?
> -Alex
> "Joe Sallustio" > wrote in message
> om...
> > Hi Alex,
> > That pH seems awful high for a TA in the range you are talking. That
> > sounds like a good Fisher Scientific or Corning pH meter, but are you
> > calibrating it right before the measurement and are you degassing the
> > sample? If so are you sure of the normality of your NAOH? If it
> > tastes tart the TA seems right...
> >
> > I take the sample to boiling for an instant prior to reading. CO2 can
> > make the pH seem falsely high.
> >
> > The right way to do it is to measure out at least 50 ml of sample,
> > degas, add distilled water back to 50 ml if necessary, cal the meter,
> > measure pH and titrate acid.
> >
> > Joe

Alex,
Your process was pretty good, the only thing I would do differently is
make sure I still had 50 ml after the heating. Add distilled water if
necessary, then pull the sample.

Vacuum degassing or purging with nitrogen may work, but I'm not a
chemist so I can't say with certainty. Margalit suggests the heating
process you used, but uses a 100 ml sample size. His book Winery
Technology is great and under $30 US. Mine is pretty worn out.

You seem to have a lot of potassium in that must. The ratio of malic
falls and tartaric rises (since it does not fall) in mature grapes.
Adding tartaric as Tom and Bill suggest will pull the potassium out
and swing the pH better than malic so I would do that too. You really
do want to cold stabilize. 25 F is faster than 40 F, but winter is
coming and that could be an option too.

I'm not as experienced as Tom and still measure and use TA. It's
easier to understand and manipulate for me since the relationship is
linear, not a log function like pH.

It's also easier for me to correlate taste to TA than pH, I have never
had a dry red with a TA over 6g/l that I thought was balanced. It's
always too tart for me. OTOH I've had the pH all over the place (from
3.45 to 3.85) on wines I like with a TA under 6 and that's a big
difference (to me).

Taste is everything though, trust your taste over optimal values in a
book. The author is not drinking your wine...

)

Joe

"Alex" > wrote in message >...
> Joe,
> I did calibrate the meter just before use and I made up the .2 M NaOH
> from a 5 M stock that is only a few weeks old. I am not so certain I
> properly degassed the wine though. I had it in a 50 ml conical tube and
> microwaved it until it was hot (not yet boiling) and I saw a bunch of
> bubbles forming on the side of the tube. I then put 15 ml in a flask and
> swirled it around for a while and waited for it to cool off before I checked
> the pH and titrated the acid. I will definitely re check it, but if nothing
> terrible will happen to the wine in the short term I will wait for
> fermentation and ML to stop completely. There is still an occasional bubble
> coming out of the air lock.
>
> In case I get anxious or for next time , can the wine be degassed properly
> by putting it under a vacuum or bubbling nitrogen through it? I have both
> of these readily available and maybe it would be more certain than just
> heating it up?
> -Alex
> "Joe Sallustio" > wrote in message
> om...
> > Hi Alex,
> > That pH seems awful high for a TA in the range you are talking. That
> > sounds like a good Fisher Scientific or Corning pH meter, but are you
> > calibrating it right before the measurement and are you degassing the
> > sample? If so are you sure of the normality of your NAOH? If it
> > tastes tart the TA seems right...
> >
> > I take the sample to boiling for an instant prior to reading. CO2 can
> > make the pH seem falsely high.
> >
> > The right way to do it is to measure out at least 50 ml of sample,
> > degas, add distilled water back to 50 ml if necessary, cal the meter,
> > measure pH and titrate acid.
> >
> > Joe