Is there a procedure for measuring the concentration of H2S in wine?
I'm just curious, that's all. I'm aware that you can use your nose to
detect rotten egg smell. I'm wondering if it's feasible to quantify the
concentration. And if there is a procedure, what is it? Thanks.

there really is no method available to home winemakers.

Commercially H2S detection tubes have been developed...I do not think
they are cheap enough for use at home though.

I don't know what you would use the info for though, it's like
wondering if you are a little pregnant. You don't want to leave H2S
alone when detected, it can turn to mercaptans which are harder to get
rid of. At least that is my understanding.

Joe

If you wanted to treat the H2S problem with CuSO4, it would be good to
know how much H2S you have, so that you can calculate how much CuSO4
you need. Otherwise, how do you know how much to add?

"Igor" > wrote in message
oups.com...
> If you wanted to treat the H2S problem with CuSO4, it would be good to
> know how much H2S you have, so that you can calculate how much CuSO4
> you need. Otherwise, how do you know how much to add?
>
Igor,

A simple way of removing H2S is to add enough copper sulfate to produce
about 0.1 ppm of copper in the wine. Then the wine should be stirred
thoroughly, and after a few minutes, the wine should be carefully smelled.
One treatment is often enough, but a second or even a third treatment may be
necessary for difficult cases. The wine should be left undisturbed for
several days after treatment so the copper sulfide (a very fine black
powder) will settle to the bottom of the container. Then the wine should be
carefully racked off the copper sulfide residue.

The following rules should be observed when using copper to remove hydrogen
sulfide odors from wine. (1) Never add copper to active fermentations.
Copper sulfate added during fermentation may cause more hydrogen sulfide to
be formed. (2) Only very small quantities of copper sulfate solution are
required, so use a pipette and measure carefully.
(3) Add the 1% copper sulfate in small (0.1 ppm) doses rather than a single
large dose. Very little copper will remain in the wine when copper sulfate
is used in this way. More copper can be added if needed, but excessive
amounts of copper are difficult to remove from wine.
(4) Never add more than 0.5 ppm of copper to any wine.

Lum
Del Mar, California, USA

Thanks Lum for the reply. Didn't you use to have a winemaking manual
online? What's the URL?

"Franco" > wrote in message
oups.com...
> Thanks Lum for the reply. Didn't you use to have a winemaking manual
> online? What's the URL?
>

Hi Franco,
The Home Winemakers Manual is still online. It just moved. The new URL is
http://www.geocities.com/lumeisenman/
Regards,
--
Lum
Del Mar, California, USA

bench trials

Well, could you explain what a bench trial is?

You take some of your wine. Treat it with increasin amounts of copper
sulfate until the H2S is gone. Then calculate how much to use on the
whole batch.

How do you know when the H2S is gone?

"Igor" > wrote in message
oups.com...
> How do you know when the H2S is gone?
>

Igor,
The human nose is very sensitive to hydrogen sulfide and it can detect about
20 parts per _billion_ (see Concepts in Wine Chemistry," page 320.
Your nose is more sensitive than many analytical interments costing hundreds
of thousands of dollars, so trust your nose. (If you can't smell it, it
ain't there.)
Good luck,
--
Lum
Del Mar, California, USA

Igor,
It is amazing how effective it is. I had to do this once and the
copper sufate really did the trick.

Just make sure wherever you get the copper sulfate gives you directions
on it's use. In general, you pull a few samples of a known quantity of
wine and add differing amounts (in drops) to the samples. It acts
almost immediately, you swirl the sample and the stink goes away. You
don't want to use any more than necessary.

Joe