"Doug" > wrote in message
om...
> "K. B." > wrote in message
om>...
> > I just bought one of those Titrets kits by Chemetrics that came with a
> > "holder" The instructions do not say how the holder works or how to use
it.
> > I have never used a Titret before, have no chemistry background and
would
> > like some guidance from the group on how to use the holder, and the
Titret
> > in terms of tips on using them.
> <<snip>>
> > KB
>
>
> KB -
> Check out this page from the Chemetrics web site:
>
> http://www.chemetrics.com/titrets.html
>
> I agree, the instructions that come with the Titrets kits are a bit
> minimal; I think they must figure most buyers are already familiar
> with them. The critical piece is that they are made with a partial
> vacuum in the glass tube. When you press the lever on the "holder",
> that allows some of the wine to be sucked up through the tube into the
> body of the titret. Hence, the important thing is to keep the open
> end of the little tube in the wine (so you get wine, not air) and do
> several very short squeezes of the lever, so that you don't overshoot
> the color change point. As indicated on the web site, the resulting
> measurement is obtained by reading the fluid level vs the scale
> printed on the side of the tube. The numbers on the scale run from
> about 10 to 100, and the Titrets package indicates that the
> measurement range is from 10 to 100 mg/L.
>
> In terms of how much SO2 is enough, the precise level isn't really
> critical, and unless you are planning on extended bottle aging,
> anything within a pretty broad range will probably be OK.
>
> As you indicated, most sources tell you to measure periodically and
> adjust the level, rather than adding all of it up front. I think
> there are two good reasons for this. First, although SO2
> concentrations do tend to drop over time, how much/how fast will vary.
> So there is no precise way to know in advance precisely how much you
> will need. Second, even if you could predict the total SO2 required
> over the wine's lifetime, you probably wouldn't want to add all of it
> in one bit dose up front, as it might inhibit the yeast, would
> interfere with things like MLF, and might cause other undesirable
> effects. Your wine would be over-sulfited during fermentation and
> most of its aging, in order to reach the "right" level at the end of
> the whole process. It might work out well enough, but it doesn't
> sound to me like an approach that is going to produce the best
> possible end result. That's my two cents.
>
> Happy fermenting -
>
> Doug


Thanks for the feedback Doug. After breaking the tip and placing it in the
wine sample, something came out of the tip and into the wine. That may be
normal- the web site indicated there was a starch solution in the tip. Is
it normal for that solution to (in the tip) to disperse into the sample?

The final reading was between 15 and 20, I drew sample in to fast (as you
warned about) and missed the exact end point. At least it gave me some
piece of mind as I had been bulk aging for some months.

KB