Fermentation, Off odours and bitter taste
One or two days after fermentation began in earnest, off odours started occuring in both batches of the Gewurztraminer.
Initially, I thought it could be a lack of yeast nutrients that was causing sulfur to form (there was a slight rotten-egg smell) and I compensated by adding a second dose of Fermaid K.
The next day the sulfur smell was gone, but other off-odours remained, and the wine started taking on a bitter, 'soapy' taste that was unpleasant. I recalled this happening a bit with my 2004 Viognier, and that wine worked out just fine, so I ignored the issue and assumed it was some VA, and it'd burn off as the fermentation progressed and dissipate further once racked off the lees.
Unfortunately, I'm now starting to think it could be either a REALLY bad case of VA, or some other type of nasty bacteriological infection The juice is now sporting a tremendously bitter taste, and the off-odours are overpowering whatever fruit might be there.
I'm not sure what, if anything, can be done at this point to pull the wine in the right direction. My best guess is to just let fermentation finish, and then hit the wine with a good dose of SO2 and rack it (with as little oxygen interaction as possible) as soon as I can.
So what have I learned? Unfortunately, I'm not sure. The vineyard I purchased the juice from hit the juice with 50ppm of SO2 at crush, so I couldn't add any more of that. I used some well-fermenting yeasts, and I used adequate yeast food. (Perhaps too much yeast food? Is this just a nasty yeast and fermentation smell?)
If anyone has any other ideas, please let me know.
On the brighter side, the Riesling is not exhibiting any such odours or tastes, and fermentation is coming along nicely. I am concerned that this wine may also encounter fermentation problems, but I'm crossing my fingers.