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 quanbreasties 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
