CuSO4 as a remedy for H2S smell?

Don't use this until you rack with splashing; it sounds like you didn't do that. I had a Grenache start developing H2S this year and after racking it off the gross lees I took the batch and dumped it through a large funnel to aerate it; it cleared up. I normally don't abuse wine like that but a red can tolerate sloppy racking when it's young.

You normally do test> I was searching past postings for info on causality, preventon, and

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I have some Merlot that has otherwise been looking great; good sugar and acid, good color, good palate - but is carrying the dreaded rotten egg odor. I have racked with moderate aeration; but am wondering what remedies might still be there if another racking or two doesn't fix the problem. Does CuSO4 work? What amounts - and how to add?

Ric

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Last year, I had a similar problem and, after a very bubbly racking, I hung a stripped copper wire into the carboy for about a week. Just added a couple copper ions to solution, and the smell went away.

Rob

Very interesting. I may try that in a bench trial. Thanks

I was unclear - that is what I meant by "racking with moderate aeration" - I racked and allowed the wine to splash into the carboy. I intend to monior (with my big nose), and rack again in 4 weeks if problem persists. If it persists after that, I will try copper. I think I'll try some bench trials with the copper wire first (see Rob's post)

- and then try a bench trial with CuSO4. What I think I need is some guidance on levels. As I understand it, apx

25% of CuSO4 is copper. And half of that will be active when applied in the wine? I also understand that something like .5% is legal limit? So if I use a 1% concentration ... etc. I need some info on those parameters.Got any thoughts?

I have heard of that and know people who just poured the wine over a piece of copper flashing. Margalit's book has good info on testing, I can get back to you on levels. Are you planning on using 1% copper sulfate if necessary? I'm pretty sure I have data on that. If racking fixes it the smell is usually gone the next day with a good rack in my experience; maybe other have had it stick around longer.

Joe

I have heard of that and know people who just poured the wine over a piece of copper flashing. Margalit's book has good info on testing, I can get back to you on levels. Are you planning on using 1% copper sulfate if necessary? I'm pretty sure I have data on that. If racking fixes it the smell is usually gone the next day with a good rack in my experience; maybe other have had it stick around longer.

Joe

I have Margalit's book - I'll look that up, thanks.

Next day, huh? Well, I guess that first racking didn't work. Per Keller's site, I am waiitng a month before another racking. Don;t know what concentration I would try - that will be determined by what I can get. Plan on seeing what I can order through the winestore outlets.

The problem with waiting is there is an increased chance the sulfides will transform to mercaptans or disulfides, which are significantly harder to get rid of. From past posts on this subjects, the copper pipe/copper sulfate thing should work within minutes.

I ran into this problem from sort of a weird angle. It's a tayberry wine that sat on the gross lees for about 10 days, but I never did get any rotten egg out of it in the carboy. But when I racked it, there was definitely something nasty there, not much but noticeable. So I tried the copper pipe treatment and it didn't seem to help. So I'm not sure what's going on but will do a mercaptan/disulfide test this weekend to hopefully rule that out.

Pp

A good explanation of what to do can be found in Lum's book. Just download it and search for copper. He talks about 1% copper sulfate which is the most common one sold. I know Presque Isle sells it, I keep it on hand; piwine/com. You should be able to find it many places. The link:

Joe

The smell took a couple of days to go fully away, but that first day was markedly better!

Rob

The smell took a couple of days to go fully away, but that first day was markedly better!

Rob

The legal limit of residual copper in commercial wine is 0.5 ppm, which is a lot lower than that!

It's generally used by adding the minimum amount of a 1% solution of copper sulfate needed to achieve removal of the stink, as determined by bench trials. Reagent copper sulfate pentahydrate (the blue, crystalline form) is

25% available copper by weight.

Tom S

If I may ask a few obvious dumba** questions: so, you just go to Home Despot, buy a length of primary, strip it, sanitize it & dangle it ? Seems a lot less mess than racking every couple of weeks! Does the wire have to hit bottom on the "cowboy" or does one use a shorter length? And is an air lock still in place?