Hello,
I am making my first red wine. I bought 550lbs of CAB from UC Davis's
Hopland research station. They said the TA was .62 and that the pH was 3.6
and the brix was 23.2. I picked the grapes about a week after they measured
this and when I got them home I found:

TA .52
pH 3.88
Brix 23+ ( I don't have a short range hydrometer I just know it is above 23
and below 23.5)

I don't know why the acid changed so much but we put the grapes in the back
of a pickup with a black bedliner. It wasn't very hot but I am wondering if
this could make the acid drop and the pH rise?

Anyways I attempted to correct this by adding some tartaric acid. I wanted
to bring up the TA to about .7 and hopefully drop the pH. I figured that
the 550lbs should yield around 30 gallons of wine so I added 1.8g/L for 118
L for a total addition of 212 grams. I took a sample of juice to my lab and
got the following:

TA 9.2
pH 3.7

So I am a little concerned. First off I don't know how the TA got so high
with this acid addition. We have a high end pH meter in my lab and yes I
calibrated it with fresh standards at pH 4, 7 and 10. Is the acid
artificially high since some of the juice is still stuck in grapes that may
not have been crushed very well? The total volume of the must is about 53
gallons and even if I messed up my original titration and I go by the
previous weeks numbers my acid addition should bring the wine from .62 to .8
which is still in the ideal range for reds. I figured 30 gallons from 550
lbs to be conservative since Lum's book says 13-14lbs of grapes for a gallon
of wine even at 15lbs/gal that would be 36 gallons. So can someone explain
how they figure the amount of acid to add when you have all those peels in
there? None of the books I have really address the issue. I have made a
few white wines and since there are no peels in the must I had no trouble
adding acid and getting it where I wanted it.

Because of circumstances I went ahead and pitched the yeast. I am not sure
I should do any more adjustments and I am hoping the acid will drop to a
normal level. Do I add the MLF culture I bought or save it for next years
wine? Any advice will be appreciated.
-Alex

Hello,
I am making my first red wine. I bought 550lbs of CAB from UC Davis's
Hopland research station. They said the TA was .62 and that the pH was
3.6
and the brix was 23.2. I picked the grapes about a week after they
measured
this and when I got them home I found:

TA .52
pH 3.88
Brix 23+ ( I don't have a short range hydrometer I just know it is above
23
and below 23.5)

I don't know why the acid changed so much but we put the grapes in the
back
of a pickup with a black bedliner. It wasn't very hot but I am wondering
if
this could make the acid drop and the pH rise?


Hi Alex,

Must sitting with the skins will experience a rise in pH and possibly a
slight rise in acid due to extraction of potassium and acids. Just a cold
soak with do this... add any amount of heat and the effect is likely to be
accelerated.

Anyways I attempted to correct this by adding some tartaric acid. I
wanted
to bring up the TA to about .7 and hopefully drop the pH. I figured that
the 550lbs should yield around 30 gallons of wine so I added 1.8g/L for
118
L for a total addition of 212 grams. I took a sample of juice to my lab
and
got the following:

TA 9.2
pH 3.7

So I am a little concerned. First off I don't know how the TA got so high
with this acid addition.



I'd check that pH again about a day or two after the addition. Adding
tartaric to red must is routine around here, and it has never shown the
adjusted reading early after the addition.

As far as your TA, I hope it's not insulting to ask how confident you are
with the test results? I never really watch mine as I don't care much
about the TA numbers once it's harvested. Quite possibly it needs time to
"settle in" before a TA reading is accurate!?.

clyde

Well everyone can make mistakes, but I measured it more than once because it
didn't seem right. I am a 5th year PhD student in biology at Stanford. I
make up lots of buffers that require pHing so I do know how to use the pH
meter but I wouldn't bet my life on it. I am sure the pH of the sample I
took is 3.7 there isn't any room for error unless our standard buffers are
bad but that is unlikely. I guess I will take another reading tomorrow and
see what it says. I hope you are right about it taking time to reach
equilibrium.
-Alex

As far as your TA, I hope it's not insulting to ask how confident you are
with the test results? I never really watch mine as I don't care much
about the TA numbers once it's harvested. Quite possibly it needs time
to
"settle in" before a TA reading is accurate!?.

clyde

"Alex" wrote in message
...
Hello,
I am making my first red wine. I bought 550lbs of CAB from UC Davis's
Hopland research station. They said the TA was .62 and that the pH was
3.6
and the brix was 23.2. I picked the grapes about a week after they
measured
this and when I got them home I found:

TA .52
pH 3.88
Brix 23+ ( I don't have a short range hydrometer I just know it is above
23
and below 23.5)

I don't know why the acid changed so much but we put the grapes in the
back
of a pickup with a black bedliner. It wasn't very hot but I am wondering
if
this could make the acid drop and the pH rise?

Anyways I attempted to correct this by adding some tartaric acid. I
wanted
to bring up the TA to about .7 and hopefully drop the pH. I figured that
the 550lbs should yield around 30 gallons of wine so I added 1.8g/L for
118
L for a total addition of 212 grams. I took a sample of juice to my lab
and
got the following:

TA 9.2
pH 3.7

So I am a little concerned. First off I don't know how the TA got so high
with this acid addition. We have a high end pH meter in my lab and yes I
calibrated it with fresh standards at pH 4, 7 and 10. Is the acid
artificially high since some of the juice is still stuck in grapes that
may
not have been crushed very well? The total volume of the must is about 53
gallons and even if I messed up my original titration and I go by the
previous weeks numbers my acid addition should bring the wine from .62 to
..8
which is still in the ideal range for reds. I figured 30 gallons from
550
lbs to be conservative since Lum's book says 13-14lbs of grapes for a
gallon
of wine even at 15lbs/gal that would be 36 gallons. So can someone
explain
how they figure the amount of acid to add when you have all those peels in
there? None of the books I have really address the issue. I have made a
few white wines and since there are no peels in the must I had no trouble
adding acid and getting it where I wanted it.

Because of circumstances I went ahead and pitched the yeast. I am not
sure
I should do any more adjustments and I am hoping the acid will drop to a
normal level. Do I add the MLF culture I bought or save it for next years
wine? Any advice will be appreciated.

I'd just leave it alone for now. Unless you're using a Bayanus strain
(Prise de Mousse, e.g.) of yeast, add the ML culture when the yeast
fermentation takes off.

You'll get better numbers later, after the wine has completed fermentation
and has degassed itself. I hope you are planning to age this in a barrel.
Cabernets really like barrel aging - preferrably French.

Tom S

Alex,
They are not pressed yet, so if you are sure of you math, and pretty
sure of your equipment, I would not worry about it. I did the same
thing this year and measured after addition and thought I screwed up
big time. (My pH followed the TA though, it was low and the TA was
way high.) If the sample was gassy, my pH read high until degassed.
If it was not, I dunno...
Regards,
Joe


Anyways I attempted to correct this by adding some tartaric acid. I wanted
to bring up the TA to about .7 and hopefully drop the pH. I figured that
the 550lbs should yield around 30 gallons of wine so I added 1.8g/L for 118
L for a total addition of 212 grams. I took a sample of juice to my lab and
got the following:

TA 9.2
pH 3.7

I took a sample of the wine last night and was going to measure the TA but
instead just measured the pH and then drank it. The pH is now reading 3.62.
I read somewhere the pH increses durring fermentation so maybe the pH is
close to where it should be. I decided to take the advice to sit it out and
see what happens.




"Joe Sallustio" wrote in message
om...
Alex,
They are not pressed yet, so if you are sure of you math, and pretty
sure of your equipment, I would not worry about it. I did the same
thing this year and measured after addition and thought I screwed up
big time. (My pH followed the TA though, it was low and the TA was
way high.) If the sample was gassy, my pH read high until degassed.
If it was not, I dunno...
Regards,
Joe


Anyways I attempted to correct this by adding some tartaric acid. I
wanted
to bring up the TA to about .7 and hopefully drop the pH. I figured
that
the 550lbs should yield around 30 gallons of wine so I added 1.8g/L for
118
L for a total addition of 212 grams. I took a sample of juice to my lab
and
got the following:

TA 9.2
pH 3.7