I work in a lab and we have 4 ph meters of different varieties we also have
cupboard full of ph strips and nitrate strips. But what ph does my wine need
to be :-( lol. Also do you people calibrate you ph meters because they drit
out alot we do 5 point calibrations on ours ever morning. Even our top rig
whic is acurate to .001 and compensates for temperature to .01 of a degree
drifts out of claibration by the end of the day. Have wine makeing
"Mark Willstatter" > wrote in message
om...
> (gus) wrote in message
. com>...
> > "LEE WEISS" > wrote in message
>.. .
> > > Plus you can measure the actual pH of the wine. Bonus.
> > > There is a procedure to follow for titrating when the pH meter goes to
8.2,
> >
> > I currently use a pH meter to check my t.t.a. also. But the blue
> > solution bottle says to take the reading when the pH = 7.0. I never
> > questioned it because I thought that 7.0 was the neutral reading.
> >
> > Should I be taking the reading at 8.2, and if so "Why"?
> >
> > Thanks,
> > Gus Calandrino
>
> The only real reason titration is done to pH 8.2 is that the
> conventional endpoint for titration is to look for color change using
> phenolphthalein as an indicator solution, which happens at pH 8.2. pH
> 7.0 would probably make more sense but TA is defined that way, at
> least in the US. As a purely practical matter, you probably won't
> observe a huge difference between using pH 7.0 and 8.2 as an endpoint;
> since pH is a logarithmic scale, it takes roughly 10x more NaOH to get
> you from pH 3 to 4 than it does from 4 to 5, ten times more from 4 to
> 5 than 5 to 6 and so forth. In other words, it will take the vast
> majority of the NaOH you add during titration to get you from pH 3.5
> to 7.0 and a tiny amount to go from 7.0 to 8.2, probably not enough to
> significantly affect your titration result.
>
> - Mark W.