Slight odor is newly-fermented wine

[Pendragon524]

I'm coming across an issue in my first few batches of wine. Regardless of the juice, they all present a slightly "off" odor, best described as rotten eggs. The taste is totally fine, so I don't think I've turned anything into vinegar, but ideally, I'd like to get to a place where my wines come out free of any gross scents. I suspect the problem is that I did not degas the must enough when racking. However, I have also heard that wine degasses naturally over time, os it could be just a matter of time before the smell goes away? Any advice would be much appreciated.

 

[Yooper]

I don't degas my wines post-fermentation, at least not usually except for kit ones. I think I've had two gassy wines that needed some help in 25+ years- so that's not it.

However, I do stir my wines in primary to degas then. It sounds like you've got some stressed yeast creating some of those off-odors of sulfur. Can you tell us your process and ingredients?

For example, I put my ingredients into a primary bucket with a loose lid or a towel covering it to keep out fruitflies and other critters, and stir about twice a day for about three days. CO2 is poisonous to yeast, so stirring helps get rid of it. It also breaks up the 'cap' that forms on top of the wine. At about day 3-5, the wine reaches 1.020 or less, and then I rack to a carboy and off of the gross lees from the fruit, and airlock. I do use yeast nutrients for many of the wines.

 

[eebowler]

Making a 7 gallon batch of portugal wine, i had a similar issue. My research resulted in the possibilities that i 1) I didn't add enough diammonium phosphate and /or 2) that my oxygenation technique was poor so the end result was the production of hydrogen sulphide (farty, rotten egg smell) because the yeast had to use internal sources of nitrogen to reproduce . To rectify that, i had to oxygenate by vigorously pouring wine from one bucket into another, three times before H2S smell was gone.

Wine turned out great in the end with no off scents!