"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