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,
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?
Hi Franco, The Home Winemakers Manual is still online. It just moved. The new URL is
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, 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,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
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