Musky smell - how to amend

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Zintrigue

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Hey everyone. I'm making my third batch of dragon blood - this time 6 gallons (yes, finally), and ran into a little snag.

The day after I pitched the yeast the wine began to carry a musky smell. The taste is unaffected, and the SG is dropping only a tiny bit slower than my 1 gallon batches.

I read this article:
http://www.eckraus.com/blog/bad-odor-during-fermentation-in-wine

From my understanding, the author recommends lowering the temperature (how, without moving the heavy thing?), and giving the yeast a little more nutrient. Then doing a bit if a shakeup during racking.

Any thoughts from you pros on the matter? Fermantation should drop below 1 tomorrow, so perhaps I'm too late?

Thanks,
-Zintrigue
 
Musky? A smell like rotten eggs suggests yeast under stress. You can whip air into the fermenter and that can dissipate the smell which is produced by hydrogen sulfide. The cause is insufficient nutrients at the beginning of the fermentation . If you are close to the end of fermentation then adding nutrients won't do anything worthwhile and may in fact encourage other off odors and flavors. Another thing to try is to rack your wine through copper scouring wool. The sulfur will bind (hopefully) with the copper and the smell will disappear.
If the smell is more like burnt matches then that suggests the presence of mercaptans and mercaptans is a product that yeast make in the presence of hydrogen sulfide (dimethyl sulfide). Mercaptans are usually a real problem to remove and the smell is one thing but they can affect the taste of the wine. You could try placing a piece of spotlessly clean and sanitized copper inside the fermenter.. (there are manufactured chemicals designed to remove mercaptans (Reduless, from Scott Labs) but I don't know how effective they are..
A third possibility if the smell is "musky" is that your wine has another kind of yeast - known as Brettanomyces. This yeast is sometimes deliberately added to beers to create "barnyard-like" odors and flavors (from mouse-like to horse-blanket), but it is often on fruit and in the air. Brett infections used to be the bane of wineries because this yeast is capable of getting into wooden barrels (literally) and fermenting the sugars in the wood. If it is , indeed, Brett, then all your glass equipment is fine but it can form a film on plastic and can be a real pain to remove. Wine makers and brewers who use Brett typically use different plastic ware.
 
Bernard, you're a very informative fellow, thank you.

I can't identify what type of musky smell it is, only that it's not the same fruitiness that I'm used to. Not really rotten eggs, not match sticks or barnyard... kind of makes me think of wet cardboard, I guess. I just went back in there to give it more of a sniff but now I can't pick it out. (just had a cup of coffee)

Either case, since the taste isn't spoiled, I'll try what you suggest. I assume I can get copper scouring wool from a hardware store? Perhaps I can clean and sanitize that and toss it in the fermenter, then run the wine through it when I rack.

Thank you very much for your input. As always, I'm glad I came here and asked.

-Zintrigue
 
My guess is that your local supermarket might carry the scrubbing wool. Ours does in upstate NY. It's sold next to the nylon dish and pot "sponges". But wet cardboard is often the "flavor" that brewers identify when their brews have oxidized. Is there any chance that oxidation may be the problem here - too much headroom after the fermentation has ceased?
 
Fermentation hasn't stopped yet, still in primary. I also wonder if it's just the strawberries in my triple berry mix, as sometimes they can put off a musky odor when cooked or soured.

Your response answered an unasked question about oxidation though. Much thanks on that :)
 

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