When I read about tartaric crystals forming in wine bottles that
haven't been cold stabilized it's usually about the visual impact and
not about lowering the acid level. Yet discussions about chilling
wine for an extended period for the purpose of precipitating tartaric
clearly indicate that acids can drop a meaningful level.

Why is there no discussion of changes in a wine's acidity post
bottling or is the typical post bottling chilling too minor to cause a
meaningful impact to acid levels?

I'm hoping that I get a substantial drop in acidity with cold stabilization of
a zin. My pH is around 3.06, due to unripe grapes, and a MLF is difficult to
start. Hopefully, if I can get the pH up to about 3.2 by chilling it down,
then the MLF might proceed. Is this too much to expect?

Lee

I seem to remember unripe fruit has a high level of Malic Acid. Cold
stablization will only percipitate Tartaric Acid.

Fred

"LG1111" > wrote in message
...
> I'm hoping that I get a substantial drop in acidity with cold
stabilization of
> a zin. My pH is around 3.06, due to unripe grapes, and a MLF is difficult
to
> start. Hopefully, if I can get the pH up to about 3.2 by chilling it
down,
> then the MLF might proceed. Is this too much to expect?
>
> Lee

>
>I seem to remember unripe fruit has a high level of Malic Acid. Cold
>stablization will only percipitate Tartaric Acid.

You're right, but if I can precipitate enough tartaric, then the pH might (??)
rise enough to be more conducin=ve to an MLF. I'm just not sure how much
change in pH one can expect with cold precip.

Lee

LG1111 ) wrote:
>>
>>I seem to remember unripe fruit has a high level of Malic Acid. Cold
>>stablization will only percipitate Tartaric Acid.

>You're right, but if I can precipitate enough tartaric, then the pH might (??)
>rise enough to be more conducin=ve to an MLF. I'm just not sure how much
>change in pH one can expect with cold precip.

>Lee

Unfortunately not. If your pH is below pH 3.6 when you cold
stabilize, your pH will DROP rather than rise with cold
stabilizaiton.

How does the wine taste? Is it acidic enough that you could remove
some acid chemically?

Dave
************************************************** **************************
Dave Breeden

"David C Breeden" > wrote in message
...
> LG1111 ) wrote:
> >>
> >>I seem to remember unripe fruit has a high level of Malic Acid. Cold
> >>stablization will only percipitate Tartaric Acid.
>
> >You're right, but if I can precipitate enough tartaric, then the pH might
(??)
> >rise enough to be more conducin=ve to an MLF. I'm just not sure how much
> >change in pH one can expect with cold precip.
>
> >Lee
>
> Unfortunately not. If your pH is below pH 3.6 when you cold
> stabilize, your pH will DROP rather than rise with cold
> stabilizaiton.
>
> How does the wine taste? Is it acidic enough that you could remove
> some acid chemically?
>
> Dave
Lee,

I agree with Dave - it is among the first things taught in wine chemistry at
university, and is related to the different dissocation curves of H2T, KHT,
and T=. Below 3.56 for wines, removing KHT actually encourages more
dissociation of H+ from the H2T, resulting in a lower pH. So cold
stabilisation will make things worse.

3.06 is not great, but you could try acclimatising your bacteria by starting
them at 3.3 or so, and gradually drop the pH before pitching. It works when
preparing yeast for sparkling tirage!

Cheers,

Andrew

Andrew/David,

Is the decrease in PH temporary? With the lower TA and aging you would
think the acids will reach some equilibrium over time?

Thanks

Joe


"Andrew L Drumm" > wrote in message
...
> "David C Breeden" > wrote in message
> ...
> > LG1111 ) wrote:
> > >>
> > >>I seem to remember unripe fruit has a high level of Malic Acid. Cold
> > >>stablization will only percipitate Tartaric Acid.
> >
> > >You're right, but if I can precipitate enough tartaric, then the pH
might
> (??)
> > >rise enough to be more conducin=ve to an MLF. I'm just not sure how
much
> > >change in pH one can expect with cold precip.
> >
> > >Lee
> >
> > Unfortunately not. If your pH is below pH 3.6 when you cold
> > stabilize, your pH will DROP rather than rise with cold
> > stabilizaiton.
> >
> > How does the wine taste? Is it acidic enough that you could remove
> > some acid chemically?
> >
> > Dave
> Lee,
>
> I agree with Dave - it is among the first things taught in wine chemistry
at
> university, and is related to the different dissocation curves of H2T,
KHT,
> and T=. Below 3.56 for wines, removing KHT actually encourages more
> dissociation of H+ from the H2T, resulting in a lower pH. So cold
> stabilisation will make things worse.
>
> 3.06 is not great, but you could try acclimatising your bacteria by
starting
> them at 3.3 or so, and gradually drop the pH before pitching. It works
when
> preparing yeast for sparkling tirage!
>
> Cheers,
>
> Andrew
>
>

Joe Ae ) wrote:
>Andrew/David,

>Is the decrease in PH temporary? With the lower TA and aging you would
>think the acids will reach some equilibrium over time?

>Thanks

>Joe


Hi Joe,

No, it's permanent.

The acids will indeed reach some equilibrium, but it may not be the
equilibrium that you want!

:-)

How does the wine taste? TA has a much greater influence on flavor
than pH.

Dave
************************************************** **************************
Dave Breeden

Lee:

The Wyeast liquid ML culture works from pH 2.9, it's based on some
Oregon strains. I've used it with good results on wines just under
3.0. The only problem is that the ML will take a long time at this pH.

Pp

(LG1111) wrote in message >...
> >
> >I seem to remember unripe fruit has a high level of Malic Acid. Cold
> >stablization will only percipitate Tartaric Acid.
>
> You're right, but if I can precipitate enough tartaric, then the pH might (??)
> rise enough to be more conducin=ve to an MLF. I'm just not sure how much
> change in pH one can expect with cold precip.
>
> Lee