i've got a batch of okanagan merlot that began the ferment @ pH 3.35
with TTA 6.0 (yes, i corrected a bit). with MLF complete, and S02
added, the wine has been in my cellar (9-10 degree C) for over a
month. at present, the pH has got rather high (3.79), the TTA is
indicating 5.8, and my free S02 is 35ppm. i'm not a terrible chemist,
and i have some faith in my numbers, derived by vacuum aspiration. so,
i pose two questions with respect to this endeavour:

1. to get the optimal (minimal) amount of mol. S02, it appears i need
around 50ppm free. i have both the australian chemistry and winemaking
guides, and they speak of only 15-20ppm required for red wine storage,
although a caveat mentions that you'll need to go a bit higher for
pH's above 3.5. I realise that my pH of essentially 3.8 would require
something past the 'slightly' higher value of 20ppm. Is my current
35ppm safe for my 400+ litres of Merlot?

2. i tested a 2002 Quail's Gate Merlot, which had a pH of 3.65. I was
shocked to find the free S02 measured less than (probably much less)
than 16ppm. a same vintage wolf blass shiraz, pH 3.5, weighed in at
14.5ppm free S02. Why are these numbers so low? Is it just that the
wine will be consumed quickly and not cellared for a long time, or is
there something else at hand?

Many thanks for any opinions or answers.
Darin

"Darin Young" wrote in message
om...
1. to get the optimal (minimal) amount of mol. S02, it appears i need
around 50ppm free. i have both the australian chemistry and winemaking
guides, and they speak of only 15-20ppm required for red wine storage,
although a caveat mentions that you'll need to go a bit higher for
pH's above 3.5. I realise that my pH of essentially 3.8 would require
something past the 'slightly' higher value of 20ppm. Is my current
35ppm safe for my 400+ litres of Merlot?

I'd say you're OK at 35 ppm, but I wouldn't go lower.

2. i tested a 2002 Quail's Gate Merlot, which had a pH of 3.65. I was
shocked to find the free S02 measured less than (probably much less)
than 16ppm. a same vintage wolf blass shiraz, pH 3.5, weighed in at
14.5ppm free S02. Why are these numbers so low? Is it just that the
wine will be consumed quickly and not cellared for a long time, or is
there something else at hand?

The free SO2 probably was higher when the wine went into bottle, but the
dissolved oxygen reacted with it and now it measures lower. The same thing
happened with my 2002 Chardonnay. It went into bottle at ~55ppm free, and 6
months later it measured ~35ppm.

FWIW, 0.8ppm molecular free SO2 is the usual target for white wines, but
many winemakers target for reds is more like 0.6ppm molecular.

Tom S

" 1. to get the optimal (minimal) amount of mol. S02, it appears i need
around 50ppm free. i have both the australian chemistry and winemaking
guides, and they speak of only 15-20ppm required for red wine storage,
although a caveat mentions that you'll need to go a bit higher for
pH's above 3.5. I realise that my pH of essentially 3.8 would require
something past the 'slightly' higher value of 20ppm. Is my current
35ppm safe for my 400+ litres of Merlot?


FWIW, 0.8ppm molecular free SO2 is the usual target for white wines, but
many winemakers target for reds is more like 0.6ppm molecular.


I calculate that you need 57 ppm to get to .6 molecular with a pH of 3.8 - I
think I'd add more SO2 assuming you'll be aging this wine for some time.

Ed

" 1. to get the optimal (minimal) amount of mol. S02, it appears i need
around 50ppm free. i have both the australian chemistry and winemaking
guides, and they speak of only 15-20ppm required for red wine storage,
although a caveat mentions that you'll need to go a bit higher for
pH's above 3.5. I realise that my pH of essentially 3.8 would require
something past the 'slightly' higher value of 20ppm. Is my current
35ppm safe for my 400+ litres of Merlot?


FWIW, 0.8ppm molecular free SO2 is the usual target for white wines, but
many winemakers target for reds is more like 0.6ppm molecular.


I calculate that you need 57 ppm to get to .6 molecular with a pH of 3.8 - I
think I'd add more SO2 assuming you'll be aging this wine for some time.

Ed

"Ed Marks" wrote in message
...

" 1. to get the optimal (minimal) amount of mol. S02, it appears i need
around 50ppm free. i have both the australian chemistry and winemaking
guides, and they speak of only 15-20ppm required for red wine storage,
although a caveat mentions that you'll need to go a bit higher for
pH's above 3.5. I realise that my pH of essentially 3.8 would require
something past the 'slightly' higher value of 20ppm. Is my current
35ppm safe for my 400+ litres of Merlot?


FWIW, 0.8ppm molecular free SO2 is the usual target for white wines, but
many winemakers target for reds is more like 0.6ppm molecular.


I calculate that you need 57 ppm to get to .6 molecular with a pH of 3.8 -
I think I'd add more SO2 assuming you'll be aging this wine for some time.

What's the structure of the wine like? Does it seem like a wine you'll lay
down for a decade+ or something you'll drink within the next few years? If
you'll be going through it pretty soon (~5 years or so) I'd leave it alone
at 35 ppm.

Tom S

" I calculate that you need 57 ppm to get to .6 molecular with a pH of
3.8 -
I think I'd add more SO2 assuming you'll be aging this wine for some
time.

What's the structure of the wine like? Does it seem like a wine you'll
lay down for a decade+ or something you'll drink within the next few
years? If you'll be going through it pretty soon (~5 years or so) I'd
leave it alone at 35 ppm.

Tom S

Tom,

What's your experience doing this? I have some wines aging now that have
higher pH than I usually get (probably in the same 3.8 range). I typically
try to keep my SO2 levels as low as possilble, but at a molecular level that
will keep the wine stable - so I shoot for .6M. Have you found that lower
levels are OK for up to 5 years? The 35 ppm that Darin has would be about
..37M - it seems that you think that's enough. Thanks for sharing your
experience with doing this.

Ed

"Ed Marks" wrote in message
...

" I calculate that you need 57 ppm to get to .6 molecular with a pH of
3.8 -
I think I'd add more SO2 assuming you'll be aging this wine for some
time.

What's the structure of the wine like? Does it seem like a wine you'll
lay down for a decade+ or something you'll drink within the next few
years? If you'll be going through it pretty soon (~5 years or so) I'd
leave it alone at 35 ppm.

Tom S

Tom,

What's your experience doing this? I have some wines aging now that have
higher pH than I usually get (probably in the same 3.8 range). I
typically try to keep my SO2 levels as low as possilble, but at a
molecular level that will keep the wine stable - so I shoot for .6M. Have
you found that lower levels are OK for up to 5 years?

I have _white_ wines that have held up for 5 years with relatively low SO2.
35 ppm should be safe enough for a red wine - but again, a lot depends on
the structure of the wine. Some wines just aren't destined to improve much
over time, no matter what the SO2 is.

Tom S

Tom & Ed, thanks for you informative comments. I ran this batch through a
mild extended maceration. So, i think it's going to take a few bottle years
for the tannins to mellow. It is extremely interesting to see how
commercial practises differ from what the typical amateur will do, following
guidance from literature rather than experience.

Anyhow, so long as my wine is ok at 35ppm free until i bottle, i'm happy.
As that event is still nearly two years away (after stainless steel and
barrel aging), i'm not sure what the pre-bottling structure will turn out to
be like. If the tannins have adequately polymerized, we'll have this one on
the table before five years. If not, i suspect more S02 and longer bottle
time will follow.

Cheers,
Darin
"Tom S" wrote in message
m...

"Ed Marks" wrote in message
...

" I calculate that you need 57 ppm to get to .6 molecular with a pH of
3.8 -
I think I'd add more SO2 assuming you'll be aging this wine for some
time.

What's the structure of the wine like? Does it seem like a wine you'll
lay down for a decade+ or something you'll drink within the next few
years? If you'll be going through it pretty soon (~5 years or so) I'd
leave it alone at 35 ppm.

Tom S

Tom,

What's your experience doing this? I have some wines aging now that have
higher pH than I usually get (probably in the same 3.8 range). I
typically try to keep my SO2 levels as low as possilble, but at a
molecular level that will keep the wine stable - so I shoot for .6M.
Have you found that lower levels are OK for up to 5 years?

I have _white_ wines that have held up for 5 years with relatively low
SO2. 35 ppm should be safe enough for a red wine - but again, a lot
depends on the structure of the wine. Some wines just aren't destined to
improve much over time, no matter what the SO2 is.

Tom S