I have just had a batch of Riesling go all H2S on me, and I can't
figure out why. I've read all the ways to fix it now that it's done,
and I'm working on those, but I want to know how to keep it from
happening on my next batch. Any comments on how to keep it from
happening to begin with, or what I've done that promoted the start of
H2S.

I used 150 lbs of ripe grapes, with just a touch of botrytis (no fuzzy
grapes, though), from a local vineyard, who also grow for local
commercial wineries. They claim that their pest control process only
uses Sulfur prior to bud-break, 3 applications total. I got the
grapes on a Friday, crushed them that afternoon, and let them sit on
their skins overnight (14 hours total). 15 gallons of must, measuring
20 brix, .62 TA, 3.1 pH (that last might be off, I'm having trouble
with my pH meter :-)). No sugar or acid adjustment. Added 15 campden
tablets, and mixed as well as I could. Pressed in the morning,
getting 6 gal free run, and 4.5 gal pressed juice, keeping them
separate. Brought up each to 50ppm sulfite.

Started the yeast later that day, using two strains from Morebeer.com
(QA23 and RHST), neither one being Montrachet, nor implicated in H2S
production before that I know of. The RHST started better than the
QA23, such that I stole a little of the float of the RHST to boost the
QA23. They ran for about a day and a half without problems, then
suddenly instead of a brown yeast cap, I suddenly had a white cap and
a heavy rotten egg smell. It's at 16 Brix, and the sulfite level went
down to about 25ppm.

Any ideas on what to do to avoid this in the future? I'd be
glad to answer any questions anyone has if it'll help figure out the
problem.

Rob

Rob,

There are a few ways to minimize the risk of H2S.

Avoid yeasts that are known to have a tendency to cause H2S such as
Montrachet. Make sure your must has adequate nutrient by adding DAP
(diammonium phosphate). Keep the wine off the autolyzed yeast as much
as possible by racking it frequently.

Others may have more suggestions.

Glen Duff
-------------------

Rob wrote:

> I have just had a batch of Riesling go all H2S on me, and I can't
> figure out why. I've read all the ways to fix it now that it's done,
> and I'm working on those, but I want to know how to keep it from
> happening on my next batch. Any comments on how to keep it from
> happening to begin with, or what I've done that promoted the start of
> H2S.
>
> I used 150 lbs of ripe grapes, with just a touch of botrytis (no fuzzy
> grapes, though), from a local vineyard, who also grow for local
> commercial wineries. They claim that their pest control process only
> uses Sulfur prior to bud-break, 3 applications total. I got the
> grapes on a Friday, crushed them that afternoon, and let them sit on
> their skins overnight (14 hours total). 15 gallons of must, measuring
> 20 brix, .62 TA, 3.1 pH (that last might be off, I'm having trouble
> with my pH meter :-)). No sugar or acid adjustment. Added 15 campden
> tablets, and mixed as well as I could. Pressed in the morning,
> getting 6 gal free run, and 4.5 gal pressed juice, keeping them
> separate. Brought up each to 50ppm sulfite.
>
> Started the yeast later that day, using two strains from Morebeer.com
> (QA23 and RHST), neither one being Montrachet, nor implicated in H2S
> production before that I know of. The RHST started better than the
> QA23, such that I stole a little of the float of the RHST to boost the
> QA23. They ran for about a day and a half without problems, then
> suddenly instead of a brown yeast cap, I suddenly had a white cap and
> a heavy rotten egg smell. It's at 16 Brix, and the sulfite level went
> down to about 25ppm.
>
> Any ideas on what to do to avoid this in the future? I'd be
> glad to answer any questions anyone has if it'll help figure out the
> problem.
>
> Rob
>

Glen Duff > wrote in message >...

Two things that come to mind:
1. The sulfite additions seems excessive, especially the second one to
bring it to 50ppm. Maybe the sulfur is coming from this?

2. Always add yeast nutrient and/or DAP as Glen said. Yeasts need
nitrogen and can develop H2S problems if they don't get enough. Also,
I heard Riesling is one the musts that can easily develop H2S, so
adequate nutrients are important. You should also consider building a
healthy yeast population by rehydrating in Startup or GoFerm and
making a starter.

Pp

> Rob,
>
> There are a few ways to minimize the risk of H2S.
>
> Avoid yeasts that are known to have a tendency to cause H2S such as
> Montrachet. Make sure your must has adequate nutrient by adding DAP
> (diammonium phosphate). Keep the wine off the autolyzed yeast as much
> as possible by racking it frequently.
>
> Others may have more suggestions.
>
> Glen Duff
> -------------------
>
> Rob wrote:
>
> > I have just had a batch of Riesling go all H2S on me, and I can't
> > figure out why. I've read all the ways to fix it now that it's done,
> > and I'm working on those, but I want to know how to keep it from
> > happening on my next batch. Any comments on how to keep it from
> > happening to begin with, or what I've done that promoted the start of
> > H2S.
> >
> > I used 150 lbs of ripe grapes, with just a touch of botrytis (no fuzzy
> > grapes, though), from a local vineyard, who also grow for local
> > commercial wineries. They claim that their pest control process only
> > uses Sulfur prior to bud-break, 3 applications total. I got the
> > grapes on a Friday, crushed them that afternoon, and let them sit on
> > their skins overnight (14 hours total). 15 gallons of must, measuring
> > 20 brix, .62 TA, 3.1 pH (that last might be off, I'm having trouble
> > with my pH meter :-)). No sugar or acid adjustment. Added 15 campden
> > tablets, and mixed as well as I could. Pressed in the morning,
> > getting 6 gal free run, and 4.5 gal pressed juice, keeping them
> > separate. Brought up each to 50ppm sulfite.
> >
> > Started the yeast later that day, using two strains from Morebeer.com
> > (QA23 and RHST), neither one being Montrachet, nor implicated in H2S
> > production before that I know of. The RHST started better than the
> > QA23, such that I stole a little of the float of the RHST to boost the
> > QA23. They ran for about a day and a half without problems, then
> > suddenly instead of a brown yeast cap, I suddenly had a white cap and
> > a heavy rotten egg smell. It's at 16 Brix, and the sulfite level went
> > down to about 25ppm.
> >
> > Any ideas on what to do to avoid this in the future? I'd be
> > glad to answer any questions anyone has if it'll help figure out the
> > problem.
> >
> > Rob
> >

I agree that the sulphite additions seemed excessive, although I've
had in the past found that my experience with campden, what should be
50ppm in a must always came out 25-30ppm after pressing. I always
assumed it was bad mixing and the pulp absorbing the addition.

That does raise another question on technique - if there's something
converting sulphite to sulfur, how do you avoid that?

Finally, I did use Go-Ferm in making the starter. The yeast,
especially the RHST, ran very strong for those first couple of hours;
I had no concern as to whether or not fermentation had begun.
Whatever happened caught up to a solid fermentation from behind and
shut it down.

For those making Riesling from grapes, how often do you rack it during
primary fermentation?

Rob


(pp) wrote in message . com>...
> Glen Duff > wrote in message >...
>
> Two things that come to mind:
> 1. The sulfite additions seems excessive, especially the second one to
> bring it to 50ppm. Maybe the sulfur is coming from this?
>
> 2. Always add yeast nutrient and/or DAP as Glen said. Yeasts need
> nitrogen and can develop H2S problems if they don't get enough. Also,
> I heard Riesling is one the musts that can easily develop H2S, so
> adequate nutrients are important. You should also consider building a
> healthy yeast population by rehydrating in Startup or GoFerm and
> making a starter.
>
> Pp
>
> > Rob,
> >
> > There are a few ways to minimize the risk of H2S.
> >
> > Avoid yeasts that are known to have a tendency to cause H2S such as
> > Montrachet. Make sure your must has adequate nutrient by adding DAP
> > (diammonium phosphate). Keep the wine off the autolyzed yeast as much
> > as possible by racking it frequently.
> >
> > Others may have more suggestions.
> >
> > Glen Duff
> > -------------------
> >
> > Rob wrote:
> >
> > > I have just had a batch of Riesling go all H2S on me, and I can't
> > > figure out why. I've read all the ways to fix it now that it's done,
> > > and I'm working on those, but I want to know how to keep it from
> > > happening on my next batch. Any comments on how to keep it from
> > > happening to begin with, or what I've done that promoted the start of
> > > H2S.
> > >
> > > I used 150 lbs of ripe grapes, with just a touch of botrytis (no fuzzy
> > > grapes, though), from a local vineyard, who also grow for local
> > > commercial wineries. They claim that their pest control process only
> > > uses Sulfur prior to bud-break, 3 applications total. I got the
> > > grapes on a Friday, crushed them that afternoon, and let them sit on
> > > their skins overnight (14 hours total). 15 gallons of must, measuring
> > > 20 brix, .62 TA, 3.1 pH (that last might be off, I'm having trouble
> > > with my pH meter :-)). No sugar or acid adjustment. Added 15 campden
> > > tablets, and mixed as well as I could. Pressed in the morning,
> > > getting 6 gal free run, and 4.5 gal pressed juice, keeping them
> > > separate. Brought up each to 50ppm sulfite.
> > >
> > > Started the yeast later that day, using two strains from Morebeer.com
> > > (QA23 and RHST), neither one being Montrachet, nor implicated in H2S
> > > production before that I know of. The RHST started better than the
> > > QA23, such that I stole a little of the float of the RHST to boost the
> > > QA23. They ran for about a day and a half without problems, then
> > > suddenly instead of a brown yeast cap, I suddenly had a white cap and
> > > a heavy rotten egg smell. It's at 16 Brix, and the sulfite level went
> > > down to about 25ppm.
> > >
> > > Any ideas on what to do to avoid this in the future? I'd be
> > > glad to answer any questions anyone has if it'll help figure out the
> > > problem.
> > >
> > > Rob
> > >

"Rob" > wrote in message
om...
> I have just had a batch of Riesling go all H2S on me, and I can't
> figure out why. I've read all the ways to fix it now that it's done,
> and I'm working on those, but I want to know how to keep it from
> happening on my next batch. Any comments on how to keep it from
> happening to begin with, or what I've done that promoted the start of
> H2S.
>
> I used 150 lbs of ripe grapes, with just a touch of botrytis (no fuzzy
> grapes, though), from a local vineyard, who also grow for local
> commercial wineries. They claim that their pest control process only
> uses Sulfur prior to bud-break, 3 applications total. I got the
> grapes on a Friday, crushed them that afternoon, and let them sit on
> their skins overnight (14 hours total). 15 gallons of must, measuring
> 20 brix, .62 TA, 3.1 pH (that last might be off, I'm having trouble
> with my pH meter :-)). No sugar or acid adjustment. Added 15 campden
> tablets, and mixed as well as I could. Pressed in the morning,
> getting 6 gal free run, and 4.5 gal pressed juice, keeping them
> separate. Brought up each to 50ppm sulfite.
>
> Started the yeast later that day, using two strains from Morebeer.com
> (QA23 and RHST), neither one being Montrachet, nor implicated in H2S
> production before that I know of. The RHST started better than the
> QA23, such that I stole a little of the float of the RHST to boost the
> QA23. They ran for about a day and a half without problems, then
> suddenly instead of a brown yeast cap, I suddenly had a white cap and
> a heavy rotten egg smell. It's at 16 Brix, and the sulfite level went
> down to about 25ppm.
>
> Any ideas on what to do to avoid this in the future?

There are 2 things you can do that would help a lot:
(1) Cold settle the juice thoroughly and rack away from the sediment prior
to fermentation.
(2) Use adequate levels of yeast nutrient, added in stages, during
fermentation.

A third suggestion is to avoid yeast strains that have a known tendency to
produce H2S.

Tom S