I seem to be having trouble getting accurate readings with sulfite titrettes
(Chemetrics in the blue box). I have several batches of wine, mostly finished
their primary fermentations, that were made either from fresh grapes (Central
Valley grapes brought in to Maryland), or from frozen buckets from Brehm.
These grapes were supposedly not treated with sulfite, but my titrations give
me values ranging from 20 ppm to 35 ppm.

The only realistic correlation that I seem to get is that if I add sufite, the
values on my titrations go up. That's about it.

So, is there any way to get more accurate readings? Can these sulfite
titrettes be "calibrated"? Or is it likely that the grapes actually have
sulfite from the vineyards?

Lee

I forgot to mention...these are all red grapes.

Lee

>I seem to be having trouble getting accurate readings with sulfite titrettes
>(Chemetrics in the blue box). I have several batches of wine, mostly
>finished
>their primary fermentations, that were made either from fresh grapes (Central
>Valley grapes brought in to Maryland), or from frozen buckets from Brehm.
>These grapes were supposedly not treated with sulfite, but my titrations give
>me values ranging from 20 ppm to 35 ppm.
>
>The only realistic correlation that I seem to get is that if I add sufite,
>the
>values on my titrations go up. That's about it.
>
>So, is there any way to get more accurate readings? Can these sulfite
>titrettes be "calibrated"? Or is it likely that the grapes actually have
>sulfite from the vineyards?
>
>Lee
>
>
>
>
>

I forgot to mention...these are all red grapes.

Lee

>I seem to be having trouble getting accurate readings with sulfite titrettes
>(Chemetrics in the blue box). I have several batches of wine, mostly
>finished
>their primary fermentations, that were made either from fresh grapes (Central
>Valley grapes brought in to Maryland), or from frozen buckets from Brehm.
>These grapes were supposedly not treated with sulfite, but my titrations give
>me values ranging from 20 ppm to 35 ppm.
>
>The only realistic correlation that I seem to get is that if I add sufite,
>the
>values on my titrations go up. That's about it.
>
>So, is there any way to get more accurate readings? Can these sulfite
>titrettes be "calibrated"? Or is it likely that the grapes actually have
>sulfite from the vineyards?
>
>Lee
>
>
>
>
>

> So, is there any way to get more accurate readings? Can these sulfite
> titrettes be "calibrated"? Or is it likely that the grapes actually have
> sulfite from the vineyards?

See sections 14.3-14.5 of http://members.tripod.com/~BRotter/SO2.htm

HTH,

Ben

GREAT WRITE-UP!!! Ben, I can't thank you enough. To others reading this, look
at Ben's whole website titled Improved Winemaking...it's really instructive.

Lee

Ben, I just read your article on MLF which I found to be equally helpful. Can
I ask you an additional question.

I've just finished the primary fermentation on a batch of what I intend to be a
Chateauneuf-du-pape blend of 1/3 syrah, 1/3 grenache, 1/3 mourvedre, and a
splash of voignier. I'm not sure whether or not to innoculate for an MLF. the
wine hasn't been sulfited yet, and it's light with a nice fruity aroma. Would
you do an MLF on this type of wine?

Thanks,

Lee

Ben, I just read your article on MLF which I found to be equally helpful. Can
I ask you an additional question.

I've just finished the primary fermentation on a batch of what I intend to be a
Chateauneuf-du-pape blend of 1/3 syrah, 1/3 grenache, 1/3 mourvedre, and a
splash of voignier. I'm not sure whether or not to innoculate for an MLF. the
wine hasn't been sulfited yet, and it's light with a nice fruity aroma. Would
you do an MLF on this type of wine?

Thanks,

Lee

LG1111 > wrote:
> I seem to be having trouble getting accurate readings with sulfite titrettes
> (Chemetrics in the blue box). I have several batches of wine, mostly finished
> their primary fermentations, that were made either from fresh grapes (Central
> Valley grapes brought in to Maryland), or from frozen buckets from Brehm.
> These grapes were supposedly not treated with sulfite, but my titrations give
> me values ranging from 20 ppm to 35 ppm.
>

I thought Brehm added sulfites to his grapes. Check the labels...

> The only realistic correlation that I seem to get is that if I add sufite, the
> values on my titrations go up. That's about it.
>
> So, is there any way to get more accurate readings? Can these sulfite
> titrettes be "calibrated"? Or is it likely that the grapes actually have
> sulfite from the vineyards?
>
> Lee

--Lee

LG1111 > wrote:
> I seem to be having trouble getting accurate readings with sulfite titrettes
> (Chemetrics in the blue box). I have several batches of wine, mostly finished
> their primary fermentations, that were made either from fresh grapes (Central
> Valley grapes brought in to Maryland), or from frozen buckets from Brehm.
> These grapes were supposedly not treated with sulfite, but my titrations give
> me values ranging from 20 ppm to 35 ppm.
>

I thought Brehm added sulfites to his grapes. Check the labels...

> The only realistic correlation that I seem to get is that if I add sufite, the
> values on my titrations go up. That's about it.
>
> So, is there any way to get more accurate readings? Can these sulfite
> titrettes be "calibrated"? Or is it likely that the grapes actually have
> sulfite from the vineyards?
>
> Lee

--Lee

(LG1111) wrote in message >...
> I seem to be having trouble getting accurate readings with sulfite titrettes
> (Chemetrics in the blue box). I have several batches of wine, mostly finished
> their primary fermentations, that were made either from fresh grapes (Central
> Valley grapes brought in to Maryland), or from frozen buckets from Brehm.
> These grapes were supposedly not treated with sulfite, but my titrations give
> me values ranging from 20 ppm to 35 ppm.
>
> The only realistic correlation that I seem to get is that if I add sufite, the
> values on my titrations go up. That's about it.
>
> So, is there any way to get more accurate readings? Can these sulfite
> titrettes be "calibrated"? Or is it likely that the grapes actually have
> sulfite from the vineyards?
>
> Lee

Whatever sulfite went into the grapes before fermentation is gone by
the end of fermentation, but yeasts will produce some small amounts of
SO2. Plus titrets generally overestimate by at least 10ppm - but I'm
sure all that is in Ben's article...

I've recently started using the Vinoferm kit for measuring SO2 - it
seems to be giving better results (and it's cheaper if testing is done
on a regular basis). The only issue is that the reagent (iodine) has
to be replaced in 1/2 year or so.

Pp

(LG1111) wrote in message >...
> I seem to be having trouble getting accurate readings with sulfite titrettes
> (Chemetrics in the blue box). I have several batches of wine, mostly finished
> their primary fermentations, that were made either from fresh grapes (Central
> Valley grapes brought in to Maryland), or from frozen buckets from Brehm.
> These grapes were supposedly not treated with sulfite, but my titrations give
> me values ranging from 20 ppm to 35 ppm.
>
> The only realistic correlation that I seem to get is that if I add sufite, the
> values on my titrations go up. That's about it.
>
> So, is there any way to get more accurate readings? Can these sulfite
> titrettes be "calibrated"? Or is it likely that the grapes actually have
> sulfite from the vineyards?
>
> Lee

Whatever sulfite went into the grapes before fermentation is gone by
the end of fermentation, but yeasts will produce some small amounts of
SO2. Plus titrets generally overestimate by at least 10ppm - but I'm
sure all that is in Ben's article...

I've recently started using the Vinoferm kit for measuring SO2 - it
seems to be giving better results (and it's cheaper if testing is done
on a regular basis). The only issue is that the reagent (iodine) has
to be replaced in 1/2 year or so.

Pp

Lee,

Thanks for the positive feedback.

Chateauneuf du Pape (or blends made of varieties used in this AOC) are
typically put through MLF. Largely, this is a stability issue - a
controlled MLF just ensures you don't get a wild one later (possibly
in bottle) etc. What's the pH and TA like on this wine? If you really
like the way the wine is now, you could just not put it through MLF,
retain that fruity aroma, and ensure stability through another method
(filtration, lysozyme).

HTH,

Ben

Is it possible that sulfur spray on the grapes is what you are reading?

> > I seem to be having trouble getting accurate readings with sulfite
titrettes
> > (Chemetrics in the blue box). I have several batches of wine, mostly
finished
> > their primary fermentations, that were made either from fresh grapes
(Central
> > Valley grapes brought in to Maryland), or from frozen buckets from
Brehm.
> > These grapes were supposedly not treated with sulfite, but my titrations
give
> > me values ranging from 20 ppm to 35 ppm.
> >
> > The only realistic correlation that I seem to get is that if I add
sufite, the
> > values on my titrations go up. That's about it.
> >
> > So, is there any way to get more accurate readings? Can these sulfite
> > titrettes be "calibrated"? Or is it likely that the grapes actually
have
> > sulfite from the vineyards?
> >
> > Lee
>
> Whatever sulfite went into the grapes before fermentation is gone by
> the end of fermentation, but yeasts will produce some small amounts of
> SO2. Plus titrets generally overestimate by at least 10ppm - but I'm
> sure all that is in Ben's article...
>
> I've recently started using the Vinoferm kit for measuring SO2 - it
> seems to be giving better results (and it's cheaper if testing is done
> on a regular basis). The only issue is that the reagent (iodine) has
> to be replaced in 1/2 year or so.
>
> Pp

Is it possible that sulfur spray on the grapes is what you are reading?

> > I seem to be having trouble getting accurate readings with sulfite
titrettes
> > (Chemetrics in the blue box). I have several batches of wine, mostly
finished
> > their primary fermentations, that were made either from fresh grapes
(Central
> > Valley grapes brought in to Maryland), or from frozen buckets from
Brehm.
> > These grapes were supposedly not treated with sulfite, but my titrations
give
> > me values ranging from 20 ppm to 35 ppm.
> >
> > The only realistic correlation that I seem to get is that if I add
sufite, the
> > values on my titrations go up. That's about it.
> >
> > So, is there any way to get more accurate readings? Can these sulfite
> > titrettes be "calibrated"? Or is it likely that the grapes actually
have
> > sulfite from the vineyards?
> >
> > Lee
>
> Whatever sulfite went into the grapes before fermentation is gone by
> the end of fermentation, but yeasts will produce some small amounts of
> SO2. Plus titrets generally overestimate by at least 10ppm - but I'm
> sure all that is in Ben's article...
>
> I've recently started using the Vinoferm kit for measuring SO2 - it
> seems to be giving better results (and it's cheaper if testing is done
> on a regular basis). The only issue is that the reagent (iodine) has
> to be replaced in 1/2 year or so.
>
> Pp

Is it possible that sulfur spray on the grapes is what you are reading?

> > I seem to be having trouble getting accurate readings with sulfite
titrettes
> > (Chemetrics in the blue box). I have several batches of wine, mostly
finished
> > their primary fermentations, that were made either from fresh grapes
(Central
> > Valley grapes brought in to Maryland), or from frozen buckets from
Brehm.
> > These grapes were supposedly not treated with sulfite, but my titrations
give
> > me values ranging from 20 ppm to 35 ppm.
> >
> > The only realistic correlation that I seem to get is that if I add
sufite, the
> > values on my titrations go up. That's about it.
> >
> > So, is there any way to get more accurate readings? Can these sulfite
> > titrettes be "calibrated"? Or is it likely that the grapes actually
have
> > sulfite from the vineyards?
> >
> > Lee
>
> Whatever sulfite went into the grapes before fermentation is gone by
> the end of fermentation, but yeasts will produce some small amounts of
> SO2. Plus titrets generally overestimate by at least 10ppm - but I'm
> sure all that is in Ben's article...
>
> I've recently started using the Vinoferm kit for measuring SO2 - it
> seems to be giving better results (and it's cheaper if testing is done
> on a regular basis). The only issue is that the reagent (iodine) has
> to be replaced in 1/2 year or so.
>
> Pp