I use grocery store distilled water to dilute wine samples for acid
titration and to replace lost volume when I boil off CO2 from samples of
wine after fermentation, acid reduction by addition of bicarb, etc. There's
been some discussion about this lately so here's the results of a Saturday
morning experiment.

I use a Presque Isle titration kit, PI buffers and sodium hydroxide
solution. I have an Omega PHH 78604 pH meter with new probe this summer.

Effect of distilled water on wine pH;
When I boil off CO2 I replace the lost volume with distilled water and then
test pH and TA.
Dilute some Brew King Super Tuscan wine with various volumes of distilled
water and test pH.

100% wine - pH 3.36
90% wine - pH 3.34
75% wine - pH 3.31
50% wine - pH 3.28

The grocery store distilled water has a pH reading. A freshly opened gallon
bottle started at pH 7.5 and drifted slowly down to 5.37 over a 5 minute
period. So, it has some acidic properties. Looks like the more distilled
water you add to a sample the more it effects pH and the trend is to give
lower than expected readings.

Effect of distilled water on wine TA;
When I do TA titrations I dilute wine samples with 100 to 200ml distilled
water. I don't measure this water and eye ball the amount in my beakers.
Test the BK Super Tuscan samples and compare to theoretical. Titrate to pH
8.2 for end point. I measured the distilled water for this experiment.

100ml distilled water, no wine - required 1 drop NaOH solution (0.05ml)
200ml distilled water, no wine - required 2 drops NaOH solution (0.01ml)

100% wine, 100ml distilled water dilution ~ 4.60ml NaOH, 0.69%TA
100% wine, 200ml distilled water dilution ~ 4.55ml NaOH, 0.68%TA
90%wine, 100ml distilled water ~ 4.0ml NaOH, 0.60%TA (theo. 0.62%)
75% wine, 100ml distilled water ~3.35ml NaOH, 0.50%TA (theo. 0.52%)
50% wine, 100ml distilled water ~ 2.2ml NaOH, 0.33%TA (theo. 0.35%)

I thought I might have to routinely run a blank and subtract the volume of
NaOH solution required to neutralize the distilled water from that used for
the wine samples. But the volume is so low it won't make a practical
difference. In this experiment there is a negative bias for actual TA
measurements compared to the theorectical. You would think if the acid
nature of distilled water made a real difference the bias would be on the
positive side.

Bill Frazier
Olathe, Kansas USA

LOL !!!

Just when I was becoming comfortable testing TA with a pH pen I am having to
consider removing CO2 and the affect of the compensating distilled water's
pH ... WHOA !

Would it be possible to pull out the CO2 by vacuum, use the sample full
strength, and forget about the other variables ???

Okay, my chemistry is pre-primary ...

Roger,
Vancouver in the RainForest




"William Frazier" wrote in message
...
I use grocery store distilled water to dilute wine samples for acid
titration and to replace lost volume when I boil off CO2 from samples of
wine after fermentation, acid reduction by addition of bicarb, etc.
There's
been some discussion about this lately so here's the results of a Saturday
morning experiment.

I use a Presque Isle titration kit, PI buffers and sodium hydroxide
solution. I have an Omega PHH 78604 pH meter with new probe this summer.

Effect of distilled water on wine pH;
When I boil off CO2 I replace the lost volume with distilled water and
then
test pH and TA.
Dilute some Brew King Super Tuscan wine with various volumes of distilled
water and test pH.

100% wine - pH 3.36
90% wine - pH 3.34
75% wine - pH 3.31
50% wine - pH 3.28

The grocery store distilled water has a pH reading. A freshly opened
gallon
bottle started at pH 7.5 and drifted slowly down to 5.37 over a 5 minute
period. So, it has some acidic properties. Looks like the more distilled
water you add to a sample the more it effects pH and the trend is to give
lower than expected readings.

Effect of distilled water on wine TA;
When I do TA titrations I dilute wine samples with 100 to 200ml distilled
water. I don't measure this water and eye ball the amount in my beakers.
Test the BK Super Tuscan samples and compare to theoretical. Titrate to
pH
8.2 for end point. I measured the distilled water for this experiment.

100ml distilled water, no wine - required 1 drop NaOH solution (0.05ml)
200ml distilled water, no wine - required 2 drops NaOH solution (0.01ml)

100% wine, 100ml distilled water dilution ~ 4.60ml NaOH, 0.69%TA
100% wine, 200ml distilled water dilution ~ 4.55ml NaOH, 0.68%TA
90%wine, 100ml distilled water ~ 4.0ml NaOH, 0.60%TA (theo. 0.62%)
75% wine, 100ml distilled water ~3.35ml NaOH, 0.50%TA (theo. 0.52%)
50% wine, 100ml distilled water ~ 2.2ml NaOH, 0.33%TA (theo. 0.35%)

I thought I might have to routinely run a blank and subtract the volume of
NaOH solution required to neutralize the distilled water from that used
for
the wine samples. But the volume is so low it won't make a practical
difference. In this experiment there is a negative bias for actual TA
measurements compared to the theorectical. You would think if the acid
nature of distilled water made a real difference the bias would be on the
positive side.

Bill Frazier
Olathe, Kansas USA

LOL !!!

Just when I was becoming comfortable testing TA with a pH pen I am having to
consider removing CO2 and the affect of the compensating distilled water's
pH ... WHOA !

Would it be possible to pull out the CO2 by vacuum, use the sample full
strength, and forget about the other variables ???

Okay, my chemistry is pre-primary ...

Roger,
Vancouver in the RainForest




"William Frazier" wrote in message
...
I use grocery store distilled water to dilute wine samples for acid
titration and to replace lost volume when I boil off CO2 from samples of
wine after fermentation, acid reduction by addition of bicarb, etc.
There's
been some discussion about this lately so here's the results of a Saturday
morning experiment.

I use a Presque Isle titration kit, PI buffers and sodium hydroxide
solution. I have an Omega PHH 78604 pH meter with new probe this summer.

Effect of distilled water on wine pH;
When I boil off CO2 I replace the lost volume with distilled water and
then
test pH and TA.
Dilute some Brew King Super Tuscan wine with various volumes of distilled
water and test pH.

100% wine - pH 3.36
90% wine - pH 3.34
75% wine - pH 3.31
50% wine - pH 3.28

The grocery store distilled water has a pH reading. A freshly opened
gallon
bottle started at pH 7.5 and drifted slowly down to 5.37 over a 5 minute
period. So, it has some acidic properties. Looks like the more distilled
water you add to a sample the more it effects pH and the trend is to give
lower than expected readings.

Effect of distilled water on wine TA;
When I do TA titrations I dilute wine samples with 100 to 200ml distilled
water. I don't measure this water and eye ball the amount in my beakers.
Test the BK Super Tuscan samples and compare to theoretical. Titrate to
pH
8.2 for end point. I measured the distilled water for this experiment.

100ml distilled water, no wine - required 1 drop NaOH solution (0.05ml)
200ml distilled water, no wine - required 2 drops NaOH solution (0.01ml)

100% wine, 100ml distilled water dilution ~ 4.60ml NaOH, 0.69%TA
100% wine, 200ml distilled water dilution ~ 4.55ml NaOH, 0.68%TA
90%wine, 100ml distilled water ~ 4.0ml NaOH, 0.60%TA (theo. 0.62%)
75% wine, 100ml distilled water ~3.35ml NaOH, 0.50%TA (theo. 0.52%)
50% wine, 100ml distilled water ~ 2.2ml NaOH, 0.33%TA (theo. 0.35%)

I thought I might have to routinely run a blank and subtract the volume of
NaOH solution required to neutralize the distilled water from that used
for
the wine samples. But the volume is so low it won't make a practical
difference. In this experiment there is a negative bias for actual TA
measurements compared to the theorectical. You would think if the acid
nature of distilled water made a real difference the bias would be on the
positive side.

Bill Frazier
Olathe, Kansas USA

"RogerD" wrote in message
news:Tio5d.155909$XP3.114627@edtnps84...
Would it be possible to pull out the CO2 by vacuum, use the sample full
strength, and forget about the other variables ???
Yep. Just get it all out.
Bill Frazier
Olathe, Kansas USA

"RogerD" wrote in message
news:Tio5d.155909$XP3.114627@edtnps84...
Would it be possible to pull out the CO2 by vacuum, use the sample full
strength, and forget about the other variables ???
Yep. Just get it all out.
Bill Frazier
Olathe, Kansas USA

Thanks for the report, Bill.

I'm wondering how much of a pH and TA difference you and others see
when removing CO2 and not removing it. As Lum points out, carbonic
acid is a weak acid and shouldn't affect readings that much. I know
this issue has been discussed many times before, but it seems like
there are so many issues involved when you try to replace lost volume
after boiling that maybe its closer to forget about the CO2. I don't
have an accurate enough pH meter to conduct such tests, so can't
report any meaningful results myself. I'm getting ready to upgrade to
a better pH meter soon.

Miker

I did some tests on wine toward the end of fermentation and it moved .02-.03
pH after boiling. This is probably negligible. It might matter if there
was more co2 in the wine like when the fermentation is more active, but I
didn't check that yet. As for the water we have an e-pure water filter
instead of distilled water in lab and it is pH 7.7 but it isn't buffered and
the wine is so the pH of the water should have a minimal affect on your
tests.
-Alex P

"Miker" wrote in message
om...
Thanks for the report, Bill.

I'm wondering how much of a pH and TA difference you and others see
when removing CO2 and not removing it. As Lum points out, carbonic
acid is a weak acid and shouldn't affect readings that much. I know
this issue has been discussed many times before, but it seems like
there are so many issues involved when you try to replace lost volume
after boiling that maybe its closer to forget about the CO2. I don't
have an accurate enough pH meter to conduct such tests, so can't
report any meaningful results myself. I'm getting ready to upgrade to
a better pH meter soon.

Miker