Critical Moment? Sulfur smell from primary fermentation

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choosybeggar

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All was proceeding swimmingly for the high gravity (1.160) blackberry/raspberry melomel with 50 ppm sulfite. Using 71B-1122 yeast @ 62F. Last Sg reading (16 hours ago) was 1.112.

I've been using SNA (1/3 FermAid+ 2/3 DAP). Added 3/4 tsp on day 0, 1,2, and day 4 when SG reached 1.112 (As I calculate the FG to be between 1.03-1.04, I estimated this was the point at which 1/3 of consumable sugars were gone.

Along with the SNA additions, I'd been vigorously stirring and degassing the must 3 times daily.

My plan was to stop nutrient additions and stop stirring vigorously at this point (oxidation concerns), but this morning, I noticed a hydrogen sulfide odor. Everything I read here suggest this is bad and ought to be remedied. I'm concerned that the remedy at this point (splashing/oxygenating the must) will result in oxidation. Also, i think I did everything right so is this possibly normal at this stage?
 
I'm unfamiliar with what Hydrogen Sulfide smells like, but if it smells like sulfur then I'd have to say that's very common with certain yeasts, and particularly when those yeasts are used in a high gravity brew.

I'd be more concerned about oxidation at this point then that, but to be honest, I'm just a beer brewer and have never made a melomel, nor any mead, nor wine, for that matter.

So maybe this was worthless. :)
 
I had the same thing happen with my first mead, fatbloke said the smell comes from yeast stress and recommended i added yeast nutrient. The smell went away after a good stirring and added yeast nutrient
 
From what i understand oxidation isnt a big concern in primary, once its time to rack to a secondary then be really careful not to splash
 
If it ain't enough, splash rack it away... Meads are very resistant to oxidation when compared to beer. I recently had a pyment get that nasty H2S smell (fart). I splash racked it twice and didn't get a single oxidation note...
If all else fails, wait until fermentation is over and perform the copper trick (google: "copper h2s smell mead" or something like it). It helped me :)
 
Thanks. Decided to add 1/2 tsp of Go Ferm and stir. Hope the stinkiness stops.
Why add a rehydration nutrient ? Instead of a fermentation nutrient ?

Your yeasties are telling you that they're stressed. The usual suggestion is to add something that contains nitrogen like Fermaidk or even DAP if its inside the first 1/3rd of the ferment, plus a bloody good stirring. The nutrient is obvious and the stirring will lift/move any particulates, which create the nucleation points for the carbonic acid to attach to and come out as gaseous CO2, which in turn helps get some O2 into the mix but also helps to lift out some of the forming H2S.

This needs to be done reasonably quickly as leaving the H2S not only is inconvenient for the stench but it can start to form mercaptans/thiols which can't be removed and ruin a batch. Hence it pays too sort it.

If its already passed the 1/3rd break then the nitrogen source should be organic like FermaidO or yeast hulls or boiled bread yeast (and a handful or two of raisins wouldn't hurt either).
 
Why add a rehydration nutrient ? Instead of a fermentation nutrient ?

Well, this is my first attempt at mead and I must confess, I'm not yet facile with all of the different possible nutrient additions.

That said, I did a little research before throwing the Go-Ferm into the tank. Here's an interesting link describing the nitrogen content of Go-Ferm, FermAid K, Superfood, and DAP (see table 3). The nitrogen in Go-Ferm is organic but present in a smaller amount than FermaidK (or presumably fermaidO) . Additionally, the recipe in Zymurgy (see image) recommended Go-Ferm in combination with fermaid-K for the SNA. What this said to me was that Go-Ferm is used in some circumstances, by some meadmakers, as a nutrient addition. Finally, I have Go Ferm on hand but not fermaid O (hadn't heard of fermaid O until your post, Fatbloke). Anyway, I figured I was good adding the Go-Ferm.

So I tossed it in, gave the must a mighty stir and...the H2S odor has diminished. :) If it comes back, I'll go for the boiled yeast and raisins. Thanks for the advice.

While I have you here, Fatbloke, could you comment on the risks of oxidation associated with vigorous stirring? I'm waaaay past the 1/3 point (although I'm hazy on how to define the 1/3 point in a sweet mead-is it 1/3 of the way to SG=1.000 or 1/3 of the way to the predicted FG which in this case is 1.03-1.04) Anyway, people say you can splash rack without worry of oxidation but then some caution to be very careful with the transfer form primary to secondary. What do you think is important to avoid mead oxidation? At what point in the fermentation do I need to start being really careful?

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Well as I understood it the nitrogen levels in GoFerm are negligable because its thought to encourage thin walled low protein yeast cells and is injurious in tbe earliest development stages....which is why it was formulated in the first place.

Yet I've also read of people successfully using goferm with DAP when theyve run out of Fermaidk.

As for the aeration ? Its recommended by many that aertion only take place down to the 1/3rd point but again I've also read of those who aerate down to 1/2 or 2/3rd points with apparently no ill effect.

The majority recommendation seems to work well for me so I'm happy to stick with it...... I still swirl my brews after the 1/3 point but don't aerate. The swirl just creates the nucleation points so the carbonic acid can come out as gaseous CO2 and helps too buffer the pH swings a little........

Equally, that recipe you post may work fine but it reads like something written by a beer maker. The practice of making very high gravity start must is one I don't necessarily agree with. I'm thinking it works in this case because of the nutrients and additional nutrient value from the fruit puree.

To my way of thinking, its much easier to start much lower, typically at about the 1.100 to 1.110 sort of area, then step feed honey to increase the alcohol levels. Also, with mels, I don't put all the fruit in up front. I either do half in primary and half as secondary or 1/3rd primary and 2/3rds secondary. That way we get a more fruity flavour that more resembles the original fruit and less of the changed fermented taste.....
 
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