I have a red wine that about a month ago developed a bad H2S problem,
because I got too busy and left it on the gross lees far too long. I
treated it with 1% CuSO4 soln until the H2S odour seemed to be gone.
I've been checking on the odour of the wine since, and it's been
reasonable. However today I sampled it and it seems to have a slight
but disturbing off note that I would say is best described as "burnt
rubber". It seemed to be more of a taste perception than odour, but
perhaps that's because I currently have a cold.

I tried searching the newsgroup archives on this but I'm not convinced
I found conclusive info. Is the burnt rubber problem caused by
disulfides as an old post suggested? If so, should I treat with
Ascorbic acid? Are there risks of making the wine worse by using
ascorbic acid and more copper?

I've been planning all along to blend this carboy of wine with another
of Merlot, and in the blending test I did today I couldn't seem to
detect the problem even though it was quite noticeable prior to
blending. My tendency would be to try and treat the problem before
blending in case it later spoils the entire lot, but I'd appreciate
advice from others with more experience with this.

Thanks in advance,
Richard

"Richard Kovach" wrote in message
om...
I have a red wine that about a month ago developed a bad H2S problem,
because I got too busy and left it on the gross lees far too long. I
treated it with 1% CuSO4 soln until the H2S odour seemed to be gone.
I've been checking on the odour of the wine since, and it's been
reasonable. However today I sampled it and it seems to have a slight
but disturbing off note that I would say is best described as "burnt
rubber". It seemed to be more of a taste perception than odour, but
perhaps that's because I currently have a cold.

I tried searching the newsgroup archives on this but I'm not convinced
I found conclusive info. Is the burnt rubber problem caused by
disulfides as an old post suggested? If so, should I treat with
Ascorbic acid? Are there risks of making the wine worse by using
ascorbic acid and more copper?

Ascorbic acid and copper is the standard treatment for dimercaptan. It's
not as fast as copper on H2S but it does work, although it may take
_months_. Also, The Wine Lab recommends treatment with Norit A (IIRC) after
the ascorbic & copper has done its thing, otherwise the stink may recur.

If you've already treated the wine with copper, you may not need to add any
more. Depends on how heavy the previous dose of copper was.

I've been planning all along to blend this carboy of wine with another
of Merlot, and in the blending test I did today I couldn't seem to
detect the problem even though it was quite noticeable prior to
blending. My tendency would be to try and treat the problem before
blending in case it later spoils the entire lot, but I'd appreciate
advice from others with more experience with this.

Fix it now, before blending. If you can't get rid of the smell don't use it
at all. No sense making two bad carboys out of one.

Tom S

Richard Kovach wrote:
I have a red wine that about a month ago developed a bad H2S problem,
because I got too busy and left it on the gross lees far too long. I
treated it with 1% CuSO4 soln until the H2S odour seemed to be gone.
I've been checking on the odour of the wine since, and it's been
reasonable. However today I sampled it and it seems to have a slight
but disturbing off note that I would say is best described as "burnt
rubber". It seemed to be more of a taste perception than odour, but
perhaps that's because I currently have a cold.

I tried searching the newsgroup archives on this but I'm not convinced
I found conclusive info. Is the burnt rubber problem caused by
disulfides as an old post suggested? If so, should I treat with
Ascorbic acid? Are there risks of making the wine worse by using
ascorbic acid and more copper?

I've been planning all along to blend this carboy of wine with another
of Merlot, and in the blending test I did today I couldn't seem to
detect the problem even though it was quite noticeable prior to
blending. My tendency would be to try and treat the problem before
blending in case it later spoils the entire lot, but I'd appreciate
advice from others with more experience with this.

Thanks in advance,
Richard

For what it's worth, as a brewer of beer, burnt rubber is associated
with yeast autolysis. I don't know if this could collerate to wine.

Brewer Bob

Thanks Tom.

I waited until my cold was gone, at which point the burnt rubber was
more noticeable as a smell and not just by taste. I finally did treat
this wine with Ascorbic acid about 36 hours ago, and the undesirable
odour/taste is greatly diminished already.

Richard

A brief update for the sake of anyone who may in the future follow
this thread in the archives:

Nearly a month after treating with ascorbic acid, the wine smells and
tastes just fine. I haven't found any need to treat with more copper
-- I'm assuming that there was still enough in solution to deal with
the mercaptans once they ascorbic acid broke down the disulfides. In
any case I'll leave in bulk storage for at least a few more months
before declaring a victory :-)

Richard

(Richard Kovach) wrote in message . com...
Thanks Tom.

I waited until my cold was gone, at which point the burnt rubber was
more noticeable as a smell and not just by taste. I finally did treat
this wine with Ascorbic acid about 36 hours ago, and the undesirable
odour/taste is greatly diminished already.

Richard

"Richard Kovach" wrote in message
om...
A brief update for the sake of anyone who may in the future follow
this thread in the archives:
............
In any case I'll leave in bulk storage for at least a few more
months before declaring a victory :-)

Richard

Not too many months, Richard. Once a wine has been fixed, as you did,
it's best drunk as soon as possible. I found that the problem has a
propensity to come back after a while....
Cheers, Giovanni.

The Wine Lab recommends that after treatment you fine with carbon (which I
think will bind with all the copper/sulfide complexes in the wine), and then
filter this out, or else the problem will definitely come back. Based on my
experience with 1 bad batch of Cab, they're right.

Ed

"Giovanni" wrote in message
newsj5Bb.609347$pl3.186336@pd7tw3no...

"Richard Kovach" wrote in message
om...
A brief update for the sake of anyone who may in the future follow
this thread in the archives:
............
In any case I'll leave in bulk storage for at least a few more
months before declaring a victory :-)

Richard

Not too many months, Richard. Once a wine has been fixed, as you did,
it's best drunk as soon as possible. I found that the problem has a
propensity to come back after a while....
Cheers, Giovanni.

I've learned the hard way that mercaptan problems are difficult to eliminate
and keep from coming back. After dealing with it a couple times to my
dissapointment, I decided to focus on prevention rather than cure. For
reds, proper nutrient for the yeast and plenty of aeration (I use rack and
return w/aeration) during primary fermentation does the trick. For whites,
propert nutrient for the yeast and selection of yeasts with very low or no
H2S production.

CHEERS!!

"Richard Kovach" wrote in message
om...
A brief update for the sake of anyone who may in the future follow
this thread in the archives:

Nearly a month after treating with ascorbic acid, the wine smells and
tastes just fine. I haven't found any need to treat with more copper
-- I'm assuming that there was still enough in solution to deal with
the mercaptans once they ascorbic acid broke down the disulfides. In
any case I'll leave in bulk storage for at least a few more months
before declaring a victory :-)

Richard

(Richard Kovach) wrote in message
. com...
Thanks Tom.

I waited until my cold was gone, at which point the burnt rubber was
more noticeable as a smell and not just by taste. I finally did treat
this wine with Ascorbic acid about 36 hours ago, and the undesirable
odour/taste is greatly diminished already.

Richard

Because wine is such a reductive environment, the tendency is always towards
forming sulphides and worse.

Aaron's right you really have to stay on top of the problem, but even doing
this you wil get the occasional sulphide problem.

If you do you need to recognise it quickly and treat appropriately - air for
ferments, DAP or other nitrogenous nutrients if the Baume is not below 4 or
5 (after this the yeast can no longer transport nutrients across the cell
wall due to inhibition by alcohol). Post ferment - rack off lees at first
sign of problems, aerate reds (watch SO2), and/or treat with Copper.

If you can deal with the sulfides, you shouldn't encounter the mercaptans
later.

Rob L

"Aaron Puhala" wrote in message
...
I've learned the hard way that mercaptan problems are difficult to
eliminate
and keep from coming back. After dealing with it a couple times to my
dissapointment, I decided to focus on prevention rather than cure. For
reds, proper nutrient for the yeast and plenty of aeration (I use rack and
return w/aeration) during primary fermentation does the trick. For
whites,
propert nutrient for the yeast and selection of yeasts with very low or no
H2S production.

CHEERS!!

"Richard Kovach" wrote in message
om...
A brief update for the sake of anyone who may in the future follow
this thread in the archives:

Nearly a month after treating with ascorbic acid, the wine smells and
tastes just fine. I haven't found any need to treat with more copper
-- I'm assuming that there was still enough in solution to deal with
the mercaptans once they ascorbic acid broke down the disulfides. In
any case I'll leave in bulk storage for at least a few more months
before declaring a victory :-)

Richard

(Richard Kovach) wrote in message
. com...
Thanks Tom.

I waited until my cold was gone, at which point the burnt rubber was
more noticeable as a smell and not just by taste. I finally did treat
this wine with Ascorbic acid about 36 hours ago, and the undesirable
odour/taste is greatly diminished already.

Richard

Ed Marks ) wrote:
The Wine Lab recommends that after treatment you fine with carbon (which I
think will bind with all the copper/sulfide complexes in the wine), and then
filter this out, or else the problem will definitely come back. Based on my
experience with 1 bad batch of Cab, they're right.

Ed

Hmm. That hasn't been my experience, either with 5 gal batchs at
home or 1000 gal batches in the winery.

And I've never used it, so I'm no expert, but I had thought
activiated carbon was sort of a last resort, that it tended to strip
wines of most of their character?

No?

Dave
************************************************** **************************
Dave Breeden

Dave,

I'm certainly not an expert here, but here's what I was told by the Wine
Lab - they said that the aggregate copper & sulfide can separate again after
a few months, and the only way to avoid this is to add deodorizing carbon to
bind with these and then remove them by filtration with a polish grade
filter. They suggest trials with the carbon to find the minimum amount that
will remove all traces of the sulfide odor and minimize the impact on other
characteristics of the wine. In their sulfide treatment instructions, they
state loudly: "WITHOUT CARBON, DISULFIDES USUALLY RE-EMERGE" (emphasis is
theirs).

Ed


"David C Breeden" wrote in message
...
Ed Marks ) wrote:
The Wine Lab recommends that after treatment you fine with carbon (which
I
think will bind with all the copper/sulfide complexes in the wine), and
then
filter this out, or else the problem will definitely come back. Based on
my
experience with 1 bad batch of Cab, they're right.

Ed

Hmm. That hasn't been my experience, either with 5 gal batchs at
home or 1000 gal batches in the winery.

And I've never used it, so I'm no expert, but I had thought
activiated carbon was sort of a last resort, that it tended to strip
wines of most of their character?

No?

Dave

************************************************** **************************
Dave Breeden

Ed Marks ) wrote:
Dave,

I'm certainly not an expert here, but here's what I was told by the Wine
Lab - they said that the aggregate copper & sulfide can separate again after
a few months, and the only way to avoid this is to add deodorizing carbon to
bind with these and then remove them by filtration with a polish grade
filter. They suggest trials with the carbon to find the minimum amount that
will remove all traces of the sulfide odor and minimize the impact on other
characteristics of the wine. In their sulfide treatment instructions, they
state loudly: "WITHOUT CARBON, DISULFIDES USUALLY RE-EMERGE" (emphasis is
theirs).

Ed


Hmm. Thta seems wierd. I usually trust the Wine Lab, but that just
doesn't even seem coherent to me, even less actually right.

If you treat the problem with copper and/or ascorbic, then it won't
smell any more. But if it doesn't smell any more, what exactly do
you look for with carbon trials? Diminution of something that's no
longer there anyway? :-)

I normally filter or rack the wine in short order after treating it,
so maybe that's why I haven't had problems: the copper-sulfide
compounds can't fall apart 'cause they're no longer there.

Dave
************************************************** **************************
Dave Breeden

You're right - I'm not really sure how to judge the effectiveness of the
carbon (obviously I got it wrong since the smell returned) - their
instructions say "The wine smells clean when the right dose of carbon is
reached". As a home wine maker without sophisticated lab resources, that's
what I went by. But maybe you've done all that was needed by filtering.

Ed


"David C Breeden" wrote in message
...
Ed Marks ) wrote:
Dave,

I'm certainly not an expert here, but here's what I was told by the Wine
Lab - they said that the aggregate copper & sulfide can separate again
after
a few months, and the only way to avoid this is to add deodorizing carbon
to
bind with these and then remove them by filtration with a polish grade
filter. They suggest trials with the carbon to find the minimum amount
that
will remove all traces of the sulfide odor and minimize the impact on
other
characteristics of the wine. In their sulfide treatment instructions,
they
state loudly: "WITHOUT CARBON, DISULFIDES USUALLY RE-EMERGE" (emphasis
is
theirs).

Ed


Hmm. Thta seems wierd. I usually trust the Wine Lab, but that just
doesn't even seem coherent to me, even less actually right.

If you treat the problem with copper and/or ascorbic, then it won't
smell any more. But if it doesn't smell any more, what exactly do
you look for with carbon trials? Diminution of something that's no
longer there anyway? :-)

I normally filter or rack the wine in short order after treating it,
so maybe that's why I haven't had problems: the copper-sulfide
compounds can't fall apart 'cause they're no longer there.

Dave

************************************************** **************************
Dave Breeden

"David C Breeden" wrote in message
...


And I've never used it, so I'm no expert, but I had thought
activiated carbon was sort of a last resort, that it tended to strip
wines of most of their character?

No?

I thought this too - people I know that make 'blank' ferments and then
flavour them afterwards use this to strip yeast/off flavours before adding
essences. Also, I've known people 'rescue' the alcohol from bad batches of
wine by stripping them with a/charcoal first, then similarly using the
resulting liquid as a blank/base for flavouring.


Cheers!

Shaun aRe - hic!

Thanks for all the info guys! I'll try and filter earlier vs later,
and in the meantime consider the carbon option.

In my case the problem came from being careless and leaving the wine
on the gross lees too long and without regular stirring. Just got too
busy with other things and pushed my luck too far. Won't be letting
*that* happen again!

Cheers,
Richard