value of ph meter
Richard Kruse
come to the conclusion that it may be of little value to by itself. Am I
correct in my conclusion? I understand the TA thing and the indirect
relationship of ph.
Dick
John DeFiore
"Richard Kruse" <rich...@gvtel.com> wrote in message
news:pG_8b.615$ow5....@news7.onvoy.net...
I don't know how I would get by without a PH meter. It's the only way I
know to tell how much SO2 I have to add to acheive a certain molecular SO2
value. I don't see why fruit or berry wines would be any different, so
I'd say it would be a very useful addition to your toolkit.
Regards,
John
Ken Anderson
news:bk2j0t$gi5$1...@bob.news.rcn.net...
probably do make wine with a technical slant. But it surprises me how often
I'll be chatting winemaking with someone, only to find out that they poo-poo
all this "technical stuff", except for the addition of sugar. I clam up,
because there's no convincing them otherwise. But out of all people who make
wine, I'll bet their category is in the majority.
Ken A.
vincent p. norris
Not sure what you mean by "indirect." If you mean "inverse," it
ain't. There is little if any relationship between pH and TA.
You can have two musts with the same TA but very different pHs.
(I speak from experience.)
vince norris
Negodki
> Not sure what you mean by "indirect." If you mean "inverse," it
> ain't. There is little if any relationship between pH and TA.
>
> You can have two musts with the same TA but very different pHs.
> (I speak from experience.)
In general, the more acidic a mixture, the lower the pH; the less
acidic the mixture, the higher the pH. Any acid correction will also
affect the pH. If the acidity and sugar are in the right range, the pH
will (probably) be as well. That is an indirect relationship.
The pH is a measure of the concentration of hydrogen atoms in
solution, and is basically a measure of the strength of the acidity.
Some acids are stronger than others. For example, sulfuric acid is
considerably stronger than tartaric. Thus two musts can have the same
TA, but very different pHs.
Tom S
> come to the conclusion that it may be of little value to by itself. Am I
> correct in my conclusion?
Absolutely NOT!
There's no way of knowing the correct amount of sulfite to add to a wine to
protect it, and still remein below the threshold of detection by
taste/smell, without measuring the pH of the juice/wine.
I quit measuring TA many years ago, but Brix and pH measurements are
*essential*.
Tom S
Joe Sallustio
I hear that too until they have problem with a batch. Then they want
the equipment to guide the decisions they want advise on. That's when
properly used and maintained equpment comes to the fore.
Probably 80% of my wines would turn out fine if I did nothing and used
no equipment. I'll never know, because I'll always measure.
I have had both very high acid musts from northeastern grapes and very
low acid musts from california that I just would not have known how
much to adjust from taste; I'm just not that dveloped yet.
I had several Pinot Noir's with an initial pH of ~3.85 and TA of ~5.2,
go figure. I guess it was mostly malic acid. If I would have used
taste alone, as time when on I'm pretty sure I would have lost them,
they never behaved as expected. I still did not prefer the end result,
but it's not bad, it's just not my best wine.
I guess that's why we call it an art, you have to develop your
instincts and do what makes the most sense to you.
I would never advise some one to fly blind if they had properly
maintained instruments, but I would never say 'trust the instruments
alone' either. That's how we got Three Mile Island as far as I am
concerned.
Regards,
Joe
... Most folks on this board (myself included)
Ben Rotter
> probably do make wine with a technical slant. But it surprises me how often
Actually I would have said it seemed the other way around. Maybe it's
just that most of the "residents" here have a technical slant, but
certainly the majority of posters do not.
On the original question (that a pH meter "may be of little value to
by itself"):
I would say you need a pH meter with a resolution that's significant
for winemaking purposes. But given that, it's an incredibly useful
tool. It gives information for SO2 useage, bacterial stability, colour
hue, acid balance, ageability...
Ben
glad heart
Am I correct then in understanding that a pH measurement reflects all
acids and is the measure required for sulfite calculations, while TA
(via NaOH neutralization) measures tartaric acid only and is valuable
for taste purposes only?
Me thinks me needs a pH meter.
Any links or recommendations for pH meter brands would be greatly
appreciated.
Jim
Paul E. Lehmann
"glad heart" <C2H5O...@yahoo.ca> wrote in message
news:ccd37cb9.03091...@posting.google.com...
> Vincent and Tom,
>
> Am I correct then in understanding that a pH measurement reflects all
> acids and is the measure required for sulfite calculations, while TA
> (via NaOH neutralization) measures tartaric acid only and is valuable
> for taste purposes only?
TA does not measure tartaric. Tartaric is merely used as a standard
reference.
But yes, you will find a pH meter VERY useful.
Tom S
>
> Am I correct then in understanding that a pH measurement reflects all
> acids and is the measure required for sulfite calculations, while TA
> (via NaOH neutralization) measures tartaric acid only and is valuable
> for taste purposes only?
Not exactly. TA measurements report the aggregate of _all_ acids in
solution as though they were tartaric. The reading from a pH meter reflects
available hydrogen ions (actually, the negative logarithm of the hydrogen
ion concentration). A pH meter gives you a better idea of practical,
_working_ acidity.
Tom S
Negodki
> Am I correct then in understanding that a pH measurement reflects all
> acids and is the measure required for sulfite calculations, while TA
> (via NaOH neutralization) measures tartaric acid only and is valuable
> for taste purposes only?
pH measures the relative strength of (all) the acid(s). TA measures
the percentage by volume of (all) the acid(s), expressed in terms of
sulphuric acid. You have to multiply by 1.5 to get the TA expressed in
terms of tartaric acid.
The pH of the must is important when determining the amount of sulfite
to be added. The higher the pH, the more sulfite is required. The
lower the pH (i.e. the more acidic the mixture), the less sulfite is
required. However, in the absence of a pH meter, one can safely assume
that 50ppm is "close enough" to the optimum amount.
The TA affects the taste of the wine. There is some relationship
between total acid and pH, but it is not a direct relationship. Thus
one can have a high TA and a low pH, or the inverse. But, any increase
in TA will result in some lowering of the pH, and any decrease in TA
will result in some increase in pH. Thus the two are related.
Furthermore, if the TA is within acceptable range, the pH is probably
also within acceptable range.
> Me thinks me needs a pH meter.
It's certainly a valuable tool to have.
Steve Small
"Tom S" <to...@spamlesspacbell.net> wrote in message
news:ljf9b.178$ps6.31...@newssvr21.news.prodigy.com...
>
> I quit measuring TA many years ago, but Brix and pH measurements are
> *essential*.
>
> Tom S
Tom - I know you have mentioned this point before - and given that I have a
decent pH meter (a matter of some debate ofcourse - but the Hanna Piccolo at
least measures down to 2 decimal places) I have wondered about how to
approach it.
If you had the Pinot Noir must mentioned by Joe (pH of ~3.85 and TA of ~5.2)
what would be your target final pH? I assume that you are adding Tartaric
acid to reach that point - and then expect to put the wine through both
cold stabilization and malolactic fermentation. So really you are probably
looking at a target ph and then a slow trend upwards as the acid changes
through the pre-bottling lifecycle of the wine.
One of the reasons I am interested in this is that I am once again faced
with chucking out a 1 year old bottle of NAOH test solution in order to
purchase something fresh for the new year - and an all pH approach can
possibly avoid this.
Finally in addressing this thread - the original poster should note that for
fruit wines, the target ph values are a little different that for grape
wines, but you issue is simplified because you will do neither a malolactic
fermentation, nor expect any cold stabilization loss since the fruit won't
have any tartaric in it.
steve
Richard Kruse
>
> The TA affects the taste of the wine. There is some relationship
> between total acid and pH, but it is not a direct relationship. Thus
> one can have a high TA and a low pH, or the inverse. But, any increase
> in TA will result in some lowering of the pH, and any decrease in TA
> will result in some increase in pH. Thus the two are related.
> Furthermore, if the TA is within acceptable range, the pH is probably
> also within acceptable range.
This is exactly the reason I posted the value in the first place. One could
sarcasticly state that
taste could almost accomplish the same thing or get a titration kit.
Thanks for the participation in this thread.
Dick
Tom S
"Negodki" <neg...@hotmail.com> wrote in message
news:8003ada.03091...@posting.google.com...
> pH measures the relative strength of (all) the acid(s). TA measures
> the percentage by volume of (all) the acid(s), expressed in terms of
> sulphuric acid. You have to multiply by 1.5 to get the TA expressed in
> terms of tartaric acid.
This highlights a difference between European and American winemaking
terminology. Here in the US, TA is expressed as tartaric. In Europe,
sulfuric acid is the reference.
Tom S
Tom S
"Steve Small" <stephe...@pleaseremove.sap.com> wrote in message
news:bk5jfl$6fi$1...@news1.wdf.sap-ag.de...
>
> "Tom S" <to...@spamlesspacbell.net> wrote in message
> news:ljf9b.178$ps6.31...@newssvr21.news.prodigy.com...
> >
> > I quit measuring TA many years ago, but Brix and pH measurements are
> > *essential*.
> >
> > Tom S
>
> Tom - I know you have mentioned this point before - and given that I have
a
> decent pH meter (a matter of some debate ofcourse - but the Hanna Piccolo
at
> least measures down to 2 decimal places) I have wondered about how to
> approach it.
>
> If you had the Pinot Noir must mentioned by Joe (pH of ~3.85 and TA of
~5.2)
> what would be your target final pH? I assume that you are adding Tartaric
> acid to reach that point - and then expect to put the wine through both
> cold stabilization and malolactic fermentation. So really you are
probably
> looking at a target ph and then a slow trend upwards as the acid changes
> through the pre-bottling lifecycle of the wine.
I think I answered that already, but I'd shoot for a starting pH of ~3.4 or
so. The wine will always try to return to its original numbers, and the pH
will rise as ML completes. It may end up at 3.6 or so, but if you do
nothing at all, the pH will go throught the roof!
Tom S
Tom S
Why sarcastically? How do you suppose this was done in years gone by, when
there were no scientific methods to follow?
Taste is the ultimate instrument for all winemakers. That is the one
standard that any wine that aspires to greatness must satisfy.
Use your meters and burettes, but be sure to _taste_ the juice!
Tom S
David C Breeden
>>
>> The TA affects the taste of the wine. There is some relationship
>> between total acid and pH, but it is not a direct relationship. Thus
>> one can have a high TA and a low pH, or the inverse. But, any increase
>> in TA will result in some lowering of the pH, and any decrease in TA
>> will result in some increase in pH. Thus the two are related.
>> Furthermore, if the TA is within acceptable range, the pH is probably
>> also within acceptable range.
<snip>
>Dick
Except that that's not always true, and can be REALLY, seriously
wrong. I've seen Pinots with TA's near 6.5 (a little high), and pH
near 4.2 (WAY too high).
Knowing the TA didn't really tell me much, but knowing the pH told
me that the wine wouldn't be long-lived.
Dave
****************************************************************************
Dave Breeden bre...@lightlink.com
Tom S
"David C Breeden" <bre...@adore.lightlink.com> wrote in message
news:3f667dfc$1...@news2.lightlink.com...
> Richard Kruse (rich...@gvtel.com) wrote:
>
> >>
> >> The TA affects the taste of the wine. There is some relationship
> >> between total acid and pH, but it is not a direct relationship. Thus
> >> one can have a high TA and a low pH, or the inverse. But, any increase
> >> in TA will result in some lowering of the pH, and any decrease in TA
> >> will result in some increase in pH. Thus the two are related.
> >> Furthermore, if the TA is within acceptable range, the pH is probably
> >> also within acceptable range.
>
> <snip>
>
> >Dick
>
> Except that that's not always true, and can be REALLY, seriously
> wrong. I've seen Pinots with TA's near 6.5 (a little high), and pH
> near 4.2 (WAY too high).
Both of those in the same wine means that the wine is high in potassium.
The solution is to hit the wine with tartaric and follow with chilling to
precipitate the excess potassium. Of course this is best done _before_
fermentation.
We had problems like that here in 1983.
Tom S
Ben Rotter
> wrong. I've seen Pinots with TA's near 6.5 (a little high), and pH
> near 4.2 (WAY too high).
>
> Knowing the TA didn't really tell me much, but knowing the pH told
> me that the wine wouldn't be long-lived.
I've noticed a tendancy in recent times on this group to ignore TA and
I know that some of the residents here don't bother measuring it. But
there's a difference between ignoring it and saying it "doesn't tell
you much".
I agree that pH is more important (read: more useful) but TA still
plays a significant role in taste (along side pH). A wine with a TA of
7 g/l at pH 3 will taste pretty different to a wine with a TA of 10
g/l at the same pH.
Ben
David C Breeden
>Tom S
Yep, you got it. 2000 ppm K+, where our other reds are more like
1000 ppm.
I wasn't working on this win until fairly late in its life. This
year, we are indeed going to make acid additions pre-ferment, and
monitor pH closely during ferment.
David C Breeden
>Ben
Right. But you could tell that by taste, rather than by titration,
no? I don't think anyone is advocating *ignoring* the TA, they're
jst saying that there's little need to measure it analytically,
unless your taste tells you that you need to modify it.
Negodki
> "Negodki" <neg...@hotmail.com> wrote:
> > pH measures the relative strength of (all) the acid(s). TA measures
> > the percentage by volume of (all) the acid(s), expressed in terms of
> > sulphuric acid. You have to multiply by 1.5 to get the TA expressed in
> > terms of tartaric acid.
>
> This highlights a difference between European and American winemaking
> terminology. Here in the US, TA is expressed as tartaric. In Europe,
> sulfuric acid is the reference.
Not really. My statement was simply in error. I was thinking of some
of the titration kits and procedures, which measure acid in terms of
sulfuric, and therefore the results must be multiplied by 1.5 to get
the TA. [Other kits, such as Carlson, factor in the multiplier by
using a larger must sample.]
But there is a difference between Europe and America in the spelling
of sulphuric (sulfuric) acid. ;-)
Negodki
> I quit measuring TA many years ago, but Brix and pH measurements are
> *essential*.
May I ask how you adjust the acidity without also measuring the TA?
If TA is known, it can be increased to the desired percentage by
adding a fixed amount of tartaric acid or acid blend (e.g. 1 tsp per
gallon per .15% deficit). There are similar formula for reducing the
acidity via dilution with 26º Brix syrup.
Is there such a formula based on the pH, or does one have to
"guestimate", play around with a test sample until target levels are
reached, and then calculate the amount needed for the larger must
volume?
Negodki
>
> I agree that pH is more important (read: more useful) but TA still
> plays a significant role in taste (along side pH). A wine with a TA of
> 7 g/l at pH 3 will taste pretty different to a wine with a TA of 10
> g/l at the same pH.
>
> Right. But you could tell that by taste, rather than by titration,
> no? I don't think anyone is advocating *ignoring* the TA, they're
> unless your taste tells you that you need to modify it.
The analytical TA measurement will tell you how much acid to add, or
how much reduction is necessary. Unless you have an extra-ordinarily
educated pallate, the only alternative would be to make a small
adjustment, taste it again, make another adjustment (perhaps in the
other direction), taste it again, ad inf.
If I know from experience that I prefer this type of wine to be at
(e.g.) 0.61% TA, I can measure the TA, compute the precise adjustment
to be made, and be done with it. If I do NOT know what I prefer, I can
still bring it to an acceptable range initially, and then perform
minute adjustments and taste tests until I get it "perfect". Either
way, the analytical data is helpful.
Furthermore, the taste test won't help much prior to fermentation,
because the sweetness overpowers the acidity. After fermentation, when
the sugar has been converted to ethynol, the taste test is very
helpful to determine IF an adjustment needs to be made. The analytical
data helps determine HOW MUCH the adjustment should be.
In the earlier example, of an acceptable TA and a extremely high pH,
it would have been obvious that "something's wrong" when I tasted the
fruit, and I wouldn't have bought the grapes! I realize this option is
not open to someone who grows their own fruit, or has a contract
obligating them to buy a particular crop regardless of quality.
Additionally, if the TA value weren't available, one might assume that
the high pH was because of low acidity, and not take steps to lower
the K level.
So, I believe both measurements are important, but --- for the
homewinemaker --- TA is the more essential.
I may change my mind by the end of this thread, though. :)
David C Breeden
>> Ben Rotter (benr...@yahoo.co.uk) wrote:
>>
>> I agree that pH is more important (read: more useful) but TA still
>> plays a significant role in taste (along side pH). A wine with a TA of
>> 7 g/l at pH 3 will taste pretty different to a wine with a TA of 10
>> g/l at the same pH.
>
>> bre...@adore.lightlink.com (David C Breeden) wrote:
>>
>> Right. But you could tell that by taste, rather than by titration,
>> no? I don't think anyone is advocating *ignoring* the TA, they're
>> just saying that there's little need to measure it analytically,
>> unless your taste tells you that you need to modify it.
>The analytical TA measurement will tell you how much acid to add, or
>how much reduction is necessary. Unless you have an extra-ordinarily
>educated pallate, the only alternative would be to make a small
>adjustment, taste it again, make another adjustment (perhaps in the
>other direction), taste it again, ad inf.
Nah. Bench trials. You can move 1/2 g/l in either direction for 2
to 3 g/l easily enough, and taste all of the resulting samples. If
I know the TA ahead of time (and if I thought wine was out of
balance, I would want to know the TA. My claim is that there's no
point in knowing it as a matter of course, because I don't adjust TA
as a amtter of course), then that might help me limit my range, but
ultimately it's my palate and the samples that tell me what to do.
The analytical data in and of itself NEVER tells me what to do.
And I can't imagine having it in mind that any wine or kind of wine
should have a particular given TA, and adjusting the wine to that
level based just on analytical data. I'm interested in making
balanced wines, not wines which conform to a preconceived notion of
chemical composition.
>Furthermore, the taste test won't help much prior to fermentation,
>because the sweetness overpowers the acidity. After fermentation, when
>the sugar has been converted to ethynol, the taste test is very
>helpful to determine IF an adjustment needs to be made. The analytical
>data helps determine HOW MUCH the adjustment should be.
Nope, you're right. Prior to fermentation, it's pH alone I worry
about. After fermentation, it's palate and pH I worry about.
>In the earlier example, of an acceptable TA and a extremely high pH,
>it would have been obvious that "something's wrong" when I tasted the
>fruit, and I wouldn't have bought the grapes! I realize this option is
>not open to someone who grows their own fruit, or has a contract
>obligating them to buy a particular crop regardless of quality.
They're my grapes. And I'm not so very sure that you could taste
what would become a high pH (remember, the TA is where it should
be). Have you been able to predict pH changes by palate in the
past? The pH of the grapes was ~3.6 or so, and with normal Brix
(~23) and normal TA (~6), I'm not sure what taste you'd look for to
predict that kind of rise in pH.
>Additionally, if the TA value weren't available, one might assume that
>the high pH was because of low acidity, and not take steps to lower
>the K level.
Egads! I guess I didn't know that there WERE ways of lowering K+
levels, other than ion exchange, which I don't have access to. What
are they?
And it may be that you and I agree more than is evident. I think
that knowing the TA is useful if and only if something is out of
whack: wierd pH, wine-out-of-balance, etc. But for a wine that I'm
happy with, with a pH that will allow it the sort of lifetime I
want, and that is typical for the varietal, I don't see any need to
know TA.
Tom S
>
> > I quit measuring TA many years ago, but Brix and pH measurements are
> > *essential*.
>
> May I ask how you adjust the acidity without also measuring the TA?
Dump in tartaric until the pH is where you want it to be.
Tom S
Tom S
> because the sweetness overpowers the acidity.
I don't agree with that. I've found that low acid juices tend to taste
flat/too sweet, and high acid juice tastes too sour. IOW, it's possible,
given experience, to tell if the juice is balanced reasonably well just by
tasting it.
Estimating by taste whether the Brix is right is a bit more difficult, but I
have a refractometer for that.
Tom S
Negodki
> ...I'm not so very sure that you could taste
> what would become a high pH (remember, the TA is where it should
> be). Have you been able to predict pH changes by palate in the
> past? The pH of the grapes was ~3.6 or so, and with normal Brix
> (~23) and normal TA (~6), I'm not sure what taste you'd look for to
> predict that kind of rise in pH.
In the example of reference (earlier in the thread), the pH was 4.2,
and the TA was 6.5, indicating the wine was quite high in potassium.
You said there were 2000 ppm K+ vs. a more normal 1000 ppm. I'm almost
certain I would be able to taste that. Potassium has a very distinct
flavour.
> Egads! I guess I didn't know that there WERE ways of lowering K+
> levels, other than ion exchange, which I don't have access to. What
> are they?
Earlier in the thread, Tom S wrote "The solution is to hit the wine
with tartaric and follow with chilling to precipitate the excess
potassium. Of course this is best done _before_fermentation."
> And it may be that you and I agree more than is evident. I think
> that knowing the TA is useful if and only if something is out of
> whack: wierd pH, wine-out-of-balance, etc. But for a wine that I'm
> happy with, with a pH that will allow it the sort of lifetime I
> want, and that is typical for the varietal, I don't see any need to
> know TA.
You are correct. In an earlier post you said "there's little need to
measure it analytically, unless your taste tells you that you need to
modify it." Somehow I missed the last part of the sentence.
Negodki
are *essential*.
Negodki: May I ask how you adjust the acidity without also measuring
the TA?
Tom: Dump in tartaric until the pH is where you want it to be.
Perhaps you misunderstood the question. If I know the TA, and I know
the desired TA ("where I want it to be"), adjustments are fairly
simple with a bit of arithmetic: 4.7 grams per gallon of typical acid
blend will raise the TA by .15. (The precise amount is usually
provided by the manufacturer on the label.)
Lowering the acid is a bit more complicated. Ideally one would blend
the (finished) wine with a low-acid wine of the same varietal to
achieve the target TA. I suppose this could (and should) be done by
taste testing, but the TA measurement gives one a good starting point.
When blending isn't an option, one gallon of water to 5 gallons of
must reduces acidity by about 10%, and 2.5 grams CaCO3 or 3.8 grams
K2CO3 per gallon will reduce the acidity by roughly .1%.
Less predictable via analytical methods: malolactic and carbonic
fermentation will lower the malic acid component. Cold stabilization
and cold fermenting will precipitate some of the potassium bitartrate.
If one only has the pH measurement available, is there a computational
method of determining the amount of acid (or water, CaCO3, or K2CO3)
to add? Or must one "guestimate" the addition conservatively, and then
test the results, and repeat this procedure until the desired pH is
achieved?
Additionally, how often do you need to replace the probes and
recalibrate the ph meter with buffer solutions?
Thanks.
David C Breeden
>Thanks.
Hi,
As I mentioned in a previous post, all the acid adjustments I do,
both up and down, are done on bench-scale first, then on the whole
volume. I had thought that this practice was absolutely routine,
not just for acid adjustments, but for ANY change to wine. I can't
seriously imagine making asjustments to wine any other way.
But heck, I also can't imagine diluting my wine or must by 20% with
water, either. :-)
So anyway, I adjust the acid up or down in 0.5 g steps, doing 5 or 6
trials, and then taste them. I gauge how much Bentonite, skim milk,
egg whites, drifine, sugar etc. to use in exactly the same way (except
I don't actually *taste* the bentonite trials). Do you do your trials
in another way, or do you not do them?
I calibrate my pH meter every day that I use it. A probe will
normally last me 3 or 4 years.
Tom S
> are *essential*.
>
> Negodki: May I ask how you adjust the acidity without also measuring
> the TA?
>
> Tom: Dump in tartaric until the pH is where you want it to be.
>
> Perhaps you misunderstood the question. If I know the TA, and I know
> the desired TA ("where I want it to be"), adjustments are fairly
> simple with a bit of arithmetic: 4.7 grams per gallon of typical acid
> blend will raise the TA by .15.
That assumes that you know what target TA you need to make the wine _taste_
right. How do you know that in advance?
I find that pH is a more reliable standard to work with, taste-wise. I like
white wines to be ~3.4-3.5, and reds a bit higher (depending on varietal).
A simple titration with tartaric acid to that pH tells me all I need to
know.
> Lowering the acid is a bit more complicated. Ideally one would blend
> the (finished) wine with a low-acid wine of the same varietal to
> achieve the target TA. I suppose this could (and should) be done by
> taste testing, but the TA measurement gives one a good starting point.
Here again, pH works better. Titrate the wine with potassium carbonate,
degas and measure the pH. Repeat if necessary, and cold stabilize to drop
out the extra K.
> When blending isn't an option, one gallon of water to 5 gallons of
> must reduces acidity by about 10%, and 2.5 grams CaCO3 or 3.8 grams
> K2CO3 per gallon will reduce the acidity by roughly .1%.
I won't even bother commenting on _that_ approach. :^P
> If one only has the pH measurement available, is there a computational
> method of determining the amount of acid (or water, CaCO3, or K2CO3)
> to add? Or must one "guestimate" the addition conservatively, and then
> test the results, and repeat this procedure until the desired pH is
> achieved?
No guessing is necessary. You simply titrate with tartaric acid until you
reach the target pH. You can _see_ it on the readout as you add the acid!
Of course you have to keep track of how much acid you added, but you can do
that by weight difference.
> Additionally, how often do you need to replace the probes and
> recalibrate the ph meter with buffer solutions?
Probes don't need to be replaced too often, and I understand that contact
lens enzyme cleaner works well to rejuvenate them. When they go bad, the
response time becomes very slow.
Calibration is not necessary very frequently unless you're into splitting
hundredths of a pH unit.
Tom S
Negodki
> But heck, I also can't imagine diluting my wine or must by 20% with
> water, either. :-)
Nor -would- I, although I did dilute some (very tart) Thompson juice
by 11.8 %. I read that NY wineries routinely add up to 30% water to
their Concord grapes to bring down the acidity. The water is usually
brought up to a brix of 24-25 by sugar additions before being mixed
in.
Remember, I did say blending was preferable. The point of mentioning
the dilution and CO3 procedures was to illustrate what I meant by
adjusting TA with a formula.
> So anyway, I adjust the acid up or down in 0.5 g steps, doing 5 or 6
> trials, and then taste them. I gauge how much Bentonite, skim milk,
> egg whites, drifine, sugar etc. to use in exactly the same way (except
> I don't actually *taste* the bentonite trials). Do you do your trials
> in another way, or do you not do them?
I do my chapitalization (when necessary) by measuring the SG. If the
sugar needs adjustment, I determine the liquid volume of the must, and
use a formula to determine the amount of sugar to be added.
I do my pre-fermentation acid adjustments (as described earlier) by
measuring the TA, determining the liquid volume, and using a formula
to determine the amount of acid to be added. I try to handle
reductions by cold-stabilization and blending, rather than dilution of
CO3 additions.
All post-fermentation adjustments and blending are done by tasting.
I don't use bentonite, skim milk, or drifine. I rarely use egg-whites,
but when I do, I use a particular amount per gallon.
This seems to work --- for me. Keep in mind, that I'm dealing with
batches that are somewhere between 1-15 gallons. If I did "bench
trials", I wouldn't have anything left to bottle.
> I calibrate my pH meter every day that I use it. A probe will normally last me 3 or 4 years.
I asked this because you and Tom have pretty much convinced me to go
out and purchase a pH meter, and use it. But when I read through the
calibration procedure in the faq, and read somewhere else that probes
last less, it didn't seem to practical for this home winemaker.
Although I make wine from apples, table grapes, and juice throughout
the year, when the vinafera are ripe I get up at 4 am, drive for an
hour to the vineyard, spend the entire morning hand-picking my grapes,
return home, spend the rest of the day destemming (by-hand) and
crushing, and the next couple of hours measuring and adjusting sugar
and acid. I'm lucky to pitch yeast by 10pm. And I'm to exhausted to do
much of anything the next couple of days.
Spending another hour or so calibrating a pH meter might kill me. :)
David C Breeden
>This seems to work --- for me. Keep in mind, that I'm dealing with
>batches that are somewhere between 1-15 gallons. If I did "bench
>trials", I wouldn't have anything left to bottle.
Yeah, that's a real issue. But for most of these trials, you can
add the wine back later.
>> I calibrate my pH meter every day that I use it. A probe will normally last me 3 or 4 years.
>I asked this because you and Tom have pretty much convinced me to go
>out and purchase a pH meter, and use it. But when I read through the
>calibration procedure in the faq, and read somewhere else that probes
>last less, it didn't seem to practical for this home winemaker.
>Although I make wine from apples, table grapes, and juice throughout
>the year, when the vinafera are ripe I get up at 4 am, drive for an
>hour to the vineyard, spend the entire morning hand-picking my grapes,
>return home, spend the rest of the day destemming (by-hand) and
>crushing, and the next couple of hours measuring and adjusting sugar
>and acid. I'm lucky to pitch yeast by 10pm. And I'm to exhausted to do
>much of anything the next couple of days.
>Spending another hour or so calibrating a pH meter might kill me. :)
:-) The procedure reads as WAY more cumbersome than it is. A
two-point calibration (all that's necessary) takes me maybe two
minutes. It's really very fast to do, but long-winded to describe.
Negodki
> That assumes that you know what target TA you need to make the wine _taste_
> right. How do you know that in advance?
The same way you know that you want your white wines to be ~3.4-3.5
pH: wine lore, rumor, and experience.
Pre-fermentation, I want my reds to be be around .65% TA, and my apple
wines to be around .7%. If I made whites, I would shoot for .75%.
Post-fermentation, I go by taste, and use the formula to effect a .01
to .05% adjustment, and then re-taste.
> I find that pH is a more reliable standard to work with, taste-wise. I like
> white wines to be ~3.4-3.5, and reds a bit higher (depending on varietal).
> A simple titration with tartaric acid to that pH tells me all I need to
> know.
You've pretty much got me convinced. :)
> Here again, pH works better. Titrate the wine with potassium carbonate,
> degas and measure the pH. Repeat if necessary, and cold stabilize to drop
> out the extra K.
Sounds simple enough.
> > When blending isn't an option, one gallon of water to 5 gallons of
> > must reduces acidity by about 10%, and 2.5 grams CaCO3 or 3.8 grams
> > K2CO3 per gallon will reduce the acidity by roughly .1%.
>
> I won't even bother commenting on _that_ approach. :^P
Which approach, the dilution or the CaCO3? I assume you don't object
to the K2CO3, since it is essentially the same procedure you mention
--- the difference being I am measuring TA and you are measuring pH. I
agree that test trials are needed, since you can't predict how much
will actually precipitate.
> No guessing is necessary. You simply titrate with tartaric acid until you
> reach the target pH. You can _see_ it on the readout as you add the acid!
> Of course you have to keep track of how much acid you added, but you can do
> that by weight difference.
Aha! So the procedure is essentially the same as the titration I do to
determine the TA, except I would be using a more relevant measurement
(pH)! Keeping track of acid added should be no more difficult than
keeping track of NaOH used. I'm beginning to like this method. :)
Now, does anyone have an opinion of the Hanna pHEP 5 digital pH meter?
Or do I need to spend a lot more for a reliable meter?
Ken Anderson
thing will get, and what with as easy as it is to compensate, do you think
I'll be happy with the thing? Iow, if it's going to see little use, is ATC
really needed? Thanks.
Ken A.
Ray
thread extremely interesting. I have been using a pH meter now for about a
year and find it very useful for most of the reasons sited. I will say that
when I have tried to adjust TA to a pre defined value after the fact, I
usually do not like the results.
But adding water to make adjustments! Several have really poo-poo this idea
and I think they have overstated the negative. Water is THE major component
in wine and of all things we could do to wine, adding water is about the
gentlest and will change the chemistry the least. Yes it will effect the
flavor but if we were not trying to effect the flavor we would not be
adjusting the wine. There is nothing wrong with adding water if it is done
intelligently and with care. This is where taste is extremely important.
We add water to many fruit wines right up front to adjust them. And if we
do not get them right up front, I see nothing wrong with further adjustment
at the end.
I made some peach wine where I used more peaches than normal. I made it
with 14-15% alcohol. I may well dilute it by 10-15%. I may not. Taste
will guide me. If I will do it with fruit wine, I will also do it with
grape wine under the right circumstances.
I avoid using water to top up with because it will change the wine. I avoid
using "similar" wines to top up with for the same reason. But in adjusting
a wine, water is just another component that can be used.
Now if adding water just totally goes against your religion ... then maybe
you should not add water! ;o)
Ray
David C Breeden
Near as I can tell, ATC is utterly useless for winemaking. While
ATC can compensate for the different interactions of H+ ions and
probe at various temperatures, it CANNOT account for the tendency of
weak organic acids (which is all you have in wine) to dissociate
less at colder temperatures, and more at higher temperatures.
ATC can lull you into a false sense of complacency and some real pH
errors.
Negodki
> Yeah, that's a real issue. But for most of these trials, you can
> add the wine back later.
Which is another great advantage of using the pH meter! When I do an
acid titration, I'm always terrified that I will accidentally pour the
sample (which now has phenothalen and NaOH in it) back into the
primary --- especially when it's 10pm and I've been up since 3am. If I
understand correctly, with the pH meter technique, all I've added to
the sample(s) is a bit of acid or carbonate, which I need to add to
the must anyway.
> >Spending another hour or so calibrating a pH meter might kill me. :)
>
> :-) The procedure reads as WAY more cumbersome than it is. A
> two-point calibration (all that's necessary) takes me maybe two
> minutes. It's really very fast to do, but long-winded to describe.
I'm beginning to realize that. I (just now) read the calibration
procedure for the meter I'm considering purchasing at
http://www.enviroequip.com/sales/phep4&5.htm, and discovered it to be
embarrasingly simple. It's easier than testing the strength of the
NaOH solution before acid titration. Rather than taking more time, and
being more complicated, as I had thought, it will probably save me
time, and be far simpler.
Thank you. I've learned a geat deal from this thread.
Lum
> I do my pre-fermentation acid adjustments (as described earlier) by
> measuring the TA, determining the liquid volume, and using a formula
I don't think predicting post fermentation TA values are all that easy. The
above technique may be OK for fruit wines but it doesn't work very well for
grape wines.
Potassium bitartrate is precipitated during fermentation and the TA drops by
0.5 to 1.5 grams per liter (tartaric). During fermentation, the yeast
produces from 0.5 to 2 grams per litter of succinic acid, so the TA
increases. See Margalit, "Concepts in Wine Chemistry," page 17, 19, 291.
Sometimes, the decrease in TA due to tartrate precipitation just about
equals the increase due to succinic acid production and the post
fermentation TA is about equal to the pre fermentation TA. But, the post
fermentation TA can be lower or higher by more than a gram per litter
depending on the fermentation parameters.
Or, am I confused again?
lum
Ben Rotter
> in wine and of all things we could do to wine, adding water is about the
> gentlest and will change the chemistry the least.
That's not really true. Adding tartaric acid effects the chemistry of
a must/wine far less than adding water. Adding tartaric will change
the TA, pH, and balance of different acids in the wine. Adding water
will change the TA, pH, colour, aroma, flavour, tannin content, SO2
content, etc etc. That's pretty drastic compared to just adding an
acid.
> Yes it will effect the flavor but if we were not trying to effect the flavor > we would not be adjusting the wine.
Usually winemakers DON'T want to adjust flavour (in fact, usually they
want to increase it, not decrease it). Dilution with water is usually
done to reduce acidity without any desire to adjust anything else. The
other adjustments that occur are consequences, and many would regard
them as negative consequences.
I'm not saying that you should never dilute your must, but it is not a
preferrable option and is generally avoided if there are reasonable
alternatives.
Ben
David C Breeden
HEY! Watch your attributions, there. *I* didn't write that. :-)
I'm with you--I don't believe that post-fermentation TA's can be
accurately guessed at, and I'd go a step further to say that it
wouldn't matter if you could or not. There is no "right" value for any
given wine, except that one that achieves balance (without screwing
up the pH).
Negodki
> > I do my pre-fermentation acid adjustments (as described earlier) by
> > measuring the TA, determining the liquid volume, and using a formula
> > to determine the amount of acid to be added. Snip.....
> "Lum" <lumei...@worldnet.att.net> wrote:
> I don't think predicting post fermentation TA values are all that easy. The
> above technique may be OK for fruit wines but it doesn't work very well for
> grape wines....
I agree that one can't (easily) predict post-fermentation TA, but one
must start somewhere. I start at .65 for reds, .7 for apples, .75 for
whites. Post-fermentation I may make another adjustment. [Also, I'm
under the impression that if the TA is too low or too high, it may
retard or prevent fermentation.]
Similarly, one can't (easily) predict post-fermentation pH (or can
they?) So, those using a pH meter start at .32-.36 (depending on the
type of wine), and make a second adustment (if needed) after
fermentation.
The methods are not that dissimilar. The primary difference is whether
TA or pH is adjusted prior to fermentation, not whether our
"predictions" are accurate.
Negodki
> > I do my pre-fermentation acid adjustments (as described earlier) by
> > measuring the TA, determining the liquid volume, and using a formula
> > to determine the amount of acid to be added. Snip.....
> "Lum" <lumei...@worldnet.att.net> wrote:
> I don't think predicting post fermentation TA values are all that easy. The
> above technique may be OK for fruit wines but it doesn't work very well for
Negodki
> Near as I can tell, ATC is utterly useless for winemaking. While
> ATC can compensate for the different interactions of H+ ions and
> probe at various temperatures, it CANNOT account for the tendency of
> weak organic acids (which is all you have in wine) to dissociate
> less at colder temperatures, and more at higher temperatures.
>
> ATC can lull you into a false sense of complacency and some real pH
> errors.
Dave, can you please elaborate on this. Are you suggesting that we
should use a meter _without_ ATC, and do the temperature adjustment
calculations manually? Or that the adjustment is irrelevant, and
should not be done?
How do we avoid the "real pH errors" you mention?
David C Breeden
So far as I know, the only way to get accurate pH measurements on
wine samples is to get the wine to a standard temperature (60-70 F
for me).
There may be some way to manually calculate pH errors vs.
temperature for weak organic acids, but you'd have to do it for all
of the different acids in wine (i.e., understand the relationship
between pKa and temperature for all those acids). It's easier to
adjust sample temps.
And yeah, I'm happier not having ATC, though if you get all your
samples totemperature anyway, it doesn't matter if it's there or
not.
Lum
> I agree that one can't (easily) predict post-fermentation TA, but one
> must start somewhere. I start at .65 for reds, .7 for apples, .75 for
> whites. Post-fermentation I may make another adjustment. [Also, I'm
> under the impression that if the TA is too low or too high, it may
> retard or prevent fermentation.]
Yeast activity is pretty much unaffected by wine acidity over the normal
range of pH and TA. See Rankine, "Making Good Wine," page 131......