I got my first acid test kit recently, but I guess I hadn't really
absorbed how they work, and I discover to my dismay that because of my
color blindness I am unable to make any kind of accurate determination
of when the end color change has occured.

Can anyone recommend or discuss the alternative methods (if any) of
acid testing for my homemade wines?

I occasionally see people here mention pH testing, but I was led to
understand that pH testing was not completely appropriate to acid
testing for wine.

As ever, the benefit of your experience and help is greatly
appreciated.

snpm

snpm ,
Google is our friend. Try this link:
http://www.forgottensea.org/medievalbrewers/acid.html

Near the very bottom the author mentions, almost in passing, that one
can use a pH meter to monitor the titration, using a pH endpoint of 8.2
for phenolpthalein indicator.

--
Mike MTM, Cokesbury, NJ, USA

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I read it, but I dont understand it at all. Im too thick for htat page
Mike, but thank you much all the same!

snpm wrote:
> I got my first acid test kit recently, but I guess I hadn't really
> absorbed how they work, and I discover to my dismay that because of my
> color blindness I am unable to make any kind of accurate determination
> of when the end color change has occured.
>
> Can anyone recommend or discuss the alternative methods (if any) of
> acid testing for my homemade wines?
>
> I occasionally see people here mention pH testing, but I was led to
> understand that pH testing was not completely appropriate to acid
> testing for wine.
>
> As ever, the benefit of your experience and help is greatly
> appreciated.
>
> snpm

snpm wrote:

> I read it, but I dont understand it at all. Im too thick for htat page
> Mike, but thank you much all the same!
Can't say I blame you. I've only skimmed the article myself, planning to
read it some nite when sleep eludes me.

The gist of it is two things:

1st: Total acidity is different from pH, and is probably the more
important measurement, tho some people differ. TA measures the full
amount of acids in the wine, but not all of that acid is in the active
or "dissociated" form. pH measures only the active form of the acid, and
that's what a pH meter shows us. Unfortunately, we can taste both active
& inactive forms of the acids, so we would want to know TA for gauging
the taste. pH just doesn't cut it for predicting taste, tho it's useful
for other things, like sulfite levels. There's no clear cut rule of
thumb for how TA & pH relate to each other; it differs in every case.

2nd: In your case, rather than looking for a color change of
phenolpthalein (indicator ) when you do a titration for TA, you can use
a pH meter to tell you when you get to the point that phenolpthalein
normally changes color. That pH point, for phenolpthalein, is 8.2 Just
do an ordinary titration, but with a pH meter in the beaker, and stop
when it reads 8.2. It's as if you went to the visual endpoint for
phenolpthalein. Many people do it this way anyway, as it's more precise
than relying on just how pink "pink" is.

(BTW, don't forget to microwave the wine sample to drive off the carbon
dioxide first. CO2 affects TA & pH.)

Another approach is to taste test and do bench tests to determine what,
if any, additions are needed. I tend to favor this approach after I've
gotten close by lab analysis.


Mike MTM, Cokesbury, NJ, USA

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"Mike McGeough" > wrote in message
...
> snpm wrote:
>
> > I read it, but I dont understand it at all. Im too thick for htat page
> > Mike, but thank you much all the same!
> Can't say I blame you. I've only skimmed the article myself, planning to
> read it some nite when sleep eludes me.
>
> The gist of it is two things:
>
> 1st: Total acidity is different from pH, and is probably the more
> important measurement, tho some people differ. TA measures the full
> amount of acids in the wine, but not all of that acid is in the active
> or "dissociated" form. pH measures only the active form of the acid, and
> that's what a pH meter shows us. Unfortunately, we can taste both active
> & inactive forms of the acids, so we would want to know TA for gauging
> the taste. pH just doesn't cut it for predicting taste, tho it's useful
> for other things, like sulfite levels. There's no clear cut rule of
> thumb for how TA & pH relate to each other; it differs in every case.
>
> 2nd: In your case, rather than looking for a color change of
> phenolpthalein (indicator ) when you do a titration for TA, you can use
> a pH meter to tell you when you get to the point that phenolpthalein
> normally changes color. That pH point, for phenolpthalein, is 8.2 Just
> do an ordinary titration, but with a pH meter in the beaker, and stop
> when it reads 8.2. It's as if you went to the visual endpoint for
> phenolpthalein. Many people do it this way anyway, as it's more precise
> than relying on just how pink "pink" is.
>
> (BTW, don't forget to microwave the wine sample to drive off the carbon
> dioxide first. CO2 affects TA & pH.)
>
> Another approach is to taste test and do bench tests to determine what,
> if any, additions are needed. I tend to favor this approach after I've
> gotten close by lab analysis.
>
>
> Mike MTM, Cokesbury, NJ, USA

Thank you for a great post Mike.
Lum
Del Mar, California, USA
www.geocities.com/lumeisenman

In article .com>, "snpm" > wrote:
>I got my first acid test kit recently, but I guess I hadn't really
>absorbed how they work, and I discover to my dismay that because of my
>color blindness I am unable to make any kind of accurate determination
>of when the end color change has occured.
>
>Can anyone recommend or discuss the alternative methods (if any) of
>acid testing for my homemade wines?

The simplest method would seem to be to ask a friend or family member who has
full color vision to help you...

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

Ah, doug, mine are few moments alone. I intend to keep my winemaking MY
winemaking, even if I have to drink brash or insipid wine. No, no help
except this newsgroup for me!



Doug Miller wrote:
> In article .com>, "snpm" > wrote:
> >I got my first acid test kit recently, but I guess I hadn't really
> >absorbed how they work, and I discover to my dismay that because of my
> >color blindness I am unable to make any kind of accurate determination
> >of when the end color change has occured.
> >
> >Can anyone recommend or discuss the alternative methods (if any) of
> >acid testing for my homemade wines?
>
> The simplest method would seem to be to ask a friend or family member who has
> full color vision to help you...
>
> --
> Regards,
> Doug Miller (alphageek at milmac dot com)
>
> It's time to throw all their damned tea in the harbor again.

On Sun, 10 Jun 2006, snpm wrote:

> I got my first acid test kit recently, but I guess I hadn't really
> absorbed how they work, and I discover to my dismay that because of my
> color blindness I am unable to make any kind of accurate determination
> of when the end color change has occured.
>
> Can anyone recommend or discuss the alternative methods (if any) of
> acid testing for my homemade wines?
>
> I occasionally see people here mention pH testing, but I was led to
> understand that pH testing was not completely appropriate to acid
> testing for wine.
>
> As ever, the benefit of your experience and help is greatly
> appreciated.

short answer: use a ph meter instead of the color change, it is more
accurate anyway.


__________________________________________________ __________________
"To create robots that devour flesh is to step over a line that we would be
insane to cross." - A Time Read The SlugBot
<http://patriot.net/~starfyr/index.html>

pH meter is the way to go.

May I recommend:

http://cgi.ebay.com/Hanna-pH-TESTER-...QQcmdZViewItem

It's the one I've use- I've benchmarked it next to our lab meters and
it's 'close enough' with calibration.

Pick up cal solutions from piwine- more of it and cheaper- and do a 2
point cal.

Jason

J. A. Holmes wrote:
> On Sun, 10 Jun 2006, snpm wrote:
>
> > I got my first acid test kit recently, but I guess I hadn't really
> > absorbed how they work, and I discover to my dismay that because of my
> > color blindness I am unable to make any kind of accurate determination
> > of when the end color change has occured.
> >
> > Can anyone recommend or discuss the alternative methods (if any) of
> > acid testing for my homemade wines?
> >
> > I occasionally see people here mention pH testing, but I was led to
> > understand that pH testing was not completely appropriate to acid
> > testing for wine.
> >
> > As ever, the benefit of your experience and help is greatly
> > appreciated.
>
> short answer: use a ph meter instead of the color change, it is more
> accurate anyway.
>
>
> __________________________________________________ __________________
> "To create robots that devour flesh is to step over a line that we would be
> insane to cross." - A Time Read The SlugBot
> <http://patriot.net/~starfyr/index.html>