Sulfur Smell in Primary

[TwoBrothers]

I am new to wine-making, and during my second batch, I noticed a rotten egg or sulfur smell in the primary fermentation phase. The smell started as soon as 36 hours after adding the yeast. I shortly realized I forgot to add the yeast nutrients which is causing the yeast to work overtime. I have since added the nutrient yeast. Will the sulfur smell dissipate naturally as fermentation continues? Is there any other step or procedure I should follow to remove any excess odor?

Thank you!

 

[ratflinger]

1/2 tsp kmeta (if 6 gal) and stir the heck out of it.

 

[sour_grapes]

Welcome to WMT!

Yes, it may dissipate if you catch it quickly enough, and follow @ratflinger 's advice.

If it is still there post-fermentation, you can treat it with Reduless.

 

[winemaker81]

That's hydrogen sulfide (H2S) -- the advice given so far is spot on!

 

[mikewatkins727]

@TwoBrothers BTW, welcome to WMT,your go-to forum for winemaking.

 

[Rice_Guy]

Welcome to WMT

Rotten egg reacts with organics to create mercaptans. These compounds are detected at parts per trillion where as fruity aromatics are parts per million. It will not go away by itself.
Good advice so far. I would suggest another step if it is still in the primary. A slow low temp ferment has lower risk of hydrogen sulfide smell. Can you decrease the temp example put milk jugs of ice in the primary? ,,, or I keep extra half gallons of juice in the freezer so I use them instead of water ice. What is your gravity? If above 1.010 I would still add Fermaid O, or any organic nutrient.

 

[NorCal]

If it is still in the throws of fermentation, I’d be hesitant on adding too much SO2, for fear of a stuck fermentation (Check the yeast tolerance). My first choice would be to do a very aggressive splash rack, over and over, bucket to bucket and the smell should blow off. The extra oxygen won’t hurt the wine and help the yeast at this growth stage. Add nutrient and hopefully the yeast will get happy.

 

[Mcjeff]

Welcome to WMT Two Brothers. A lot of helpful people on here.

Since we are talking about this. I could use some help. I’m at the end of fermentation - plan to press today or tomorrow and my Cab Sauv has a little smell when I punch down. Too late to add more yeast nutrients (I added fermaid O earlier) and I co inoculated my Malo so I didn’t want to add KMeta but maybe I need to? Splash rack or will pressing blow it off and I’ll be fine? Any thoughts?

My Sangiovese with a higher starting Brix smells great.

 

[winemaker81]

Since we are talking about this. I could use some help. I’m at the end of fermentation - plan to press today or tomorrow and my Cab Sauv has a little smell when I punch down. Too late to add more yeast nutrients (I added fermaid O earlier) and I co inoculated my Malo so I didn’t want to add KMeta but maybe I need to? Splash rack or will pressing blow it off and I’ll be fine? Any thoughts?

What is the SG? If it's below 1.010, adding nutrient is probably a wasted effort.

Since it's grape, you can't splash rack, so stir the heck out of it to drive off the H2S. If it's a light smell, this may be sufficient.

If the smell goes away, you're probably fine. If it doesn't go away or gets worse, add K-meta. That will probably scotch the MLF, but eliminating H2S is the higher concern.

 

[Mcjeff]

Thanks. I was thinking that approach. Yes SG is below 1 now. I stirred heavily this morning when I was punching down I’ll press tonight and hope it handles it. If not go ahead and add Kmeta.

 

[Donnab1045]

Welcome to WMT Two Brothers. A lot of helpful people on here.

Since we are talking about this. I could use some help. I’m at the end of fermentation - plan to press today or tomorrow and my Cab Sauv has a little smell when I punch down. Too late to add more yeast nutrients (I added fermaid O earlier) and I co inoculated my Malo so I didn’t want to add KMeta but maybe I need to? Splash rack or will pressing blow it off and I’ll be fine? Any thoughts?

My Sangiovese with a higher starting Brix smells great.

Just splash rack big. Aim the outgoing hose against the side of a large open fermenter. If you have a piece of copper tubing, shine it up with steel wool, and splash rack over it. Don’t leave the tubing in very long. Or, use redulees. Just remedy it early before it converts to mercaptins.

 

[NorCal]

Just splash rack big. Aim the outgoing hose against the side of a large open fermenter. If you have a piece of copper tubing, shine it up with steel wool, and splash rack over it. Don’t leave the tubing in very long. Or, use redulees. Just remedy it early before it converts to mercaptins.

I highly suggest not using a copper pipe to remedy H2S, which would give you an uncontrolled amount of copper in your wine. Some people have bad reactions to heavy metals in their systems.
The active ingredient in redulees is copper, but it is a small and controlled amount, which precipitates out of solution.

 

[RylanJacobs]

I dealt with H2S earlier this year. Stirring/splash racking are all great choices as it does *reduce* the smell. However, the smell was fully eliminated with the following:

1) Reduless added, stirred gently
2) 72 hours later, added Kieselsol and Chitosan to clear
3) 1 week later, splash racked to secondary with 50PPM k-meta addition

The wine has been bulk aging ever since without a trace of H2S. I'm not going to win any love from the natural winemaking crowd, but this got the job done and the wine is enjoyable. Going to bottle soon.

 

[winemaker81]

How early H2S is caught makes a huge difference. This year in the juice bucket I barely caught whiff, added K-meta and stirred vigorously. There was no reoccurrence.

In 2020 I caught it late, and had to do the full treatment, including ascorbic acid to eliminate the mercaptan.

Once H2S has been smelled, it's hard to forget, even with a lobotomy. If anyone catches a whiff, react immediately!

 

[TwoBrothers]

Thank you everyone for your advice and warm welcomes! I stirred vigorously throughout the primary fermentation. I also added the suggested kmeta. The smell dissipated relatively quickly; however, I kept the vigorous stirring throughout the process to remove any extra residue. The wine smells great. Will be racking shortly as the gravity level is approaching 1.000. Again, thank you everyone for the warm welcomes and the fantastic advice.