Sulfur smell detected

[Siwash]

Hey folks,

I have two carboys that both smell of sulfur (I think that is what I smell)... a bit of a burnt smell... I've read about this. I have also come across Rudeless. It's supposed to remove the sulfur odour. Any experience with this?

Thanks

 

[winemaker81]

If it smells like burnt matches, it's probably a high level of free SO2. How much K-meta did you add?

There isn't much that can be done to address too much K-meta -- the best suggestion is to rack it, which will allow some free SO2 to escape. While it's probably not dangerous levels, I suggest doing it in a ventilated area and run a fan, just to give your lungs a break.

Time is also a friend, as the free SO2 will get used up. While I no longer rack every 3 months during bulk aging, you may want to bulk age a year, racking every 3 months to let excess SO2 escape. If you no longer smell the burnt smell, stop the rackings.

Blending with other wines will also reduce the average level of SO2.

If it was H2S, the wine would smell like swamp gas and/or dog farts, truly noxious. I found this article, which may help.

https://extension.psu.edu/sulfur-based-off-flavors-in-wine

 

[Siwash]

Well, I'm glad I don't own a dog - I have no clue what dog farts smell like.

I am pretty sure that it's more of a burnt smell. I'll check again. Not sure it's burnt match but I have been under the weather and my sense of smell has been off a bit the past couple of weeks.

Thanks for the input. I guess that product isn't worth it.

I do rack every 3 months or so. I've added k meta each time - one teaspoon each carboy. Maybe I need to back off on it!

Thanks!!

 

[Siwash]

Just thought about this - - Could it be malic acid? Does that give off an odour? I didn't do an MLF

 

[winemaker81]

I've added k meta each time - one teaspoon each carboy. Maybe I need to back off on it!

THAT is your problem. The normal dosage is 1/4 tsp for 5 or 6 gallons.

If the product you mean is Reduless, it's a very useful product -- IF you have H2S and didn't catch it early. The first treatment for H2S is hard stirring and adding K-meta. If that doesn't work, then a copper-based product such as Reduless can be used, followed by fining to ensure the copper precipitates.

 

[Siwash]

Smells more like something burnt... so probably excess sulphite, as you said. A few years ago, my brother-in-law said a wine I made had a bit more of a "green pepper" odor, so more of a vegetative aroma (if that's a thing?), and he said it could be due to malic acid? I wonder if this is the same phenomenon or just excess So2

As for SO2 additions, should I add that 1/4 tsp recommendation even for the initial dose of k-meta (after I am completely done fermentation and commence bulk aging)?

 

[winemaker81]

Malic the predominant acid in apples, which gives them their tang. Vegetative aromas can come from the fruit -- some yeast are listed as removing vegetative aroma and flavor.

For the wines that you added 1 tsp/5 gallons? Don't add more K-meta -- you already have added 4 times the recommended amount. Depending on how many times you added K-meta, you may not want to add more.

For wines that have not been so treated, I add 1/4 tsp K-meta at each racking, post-fermentation, and at bottling.

Another option -- if you have wine that has not received K-meta, you can blend it with the wine that is over-dosed.