Off Odor

Hi David,

Bocksin is the only additive that I've heard of that may be able to put a dent in your burnt rubber off odor which is likely mercaptans caused by a reductive fermentation and the production of Hydrogen Sulfide gas. I'm not sure, however, how well Bocksin works on mercaptans which are much harder to remove from a wine than H2S. I suggest you try it on a small quantity first to see if it works.

As an aside... When I started making wine I was plagued by this "burn rubber" problem. I thought I wasn't being "clean enough" or wasn't being carefull enough about toppng up to prevent oxidation. After tying (without success!) to be cleaner and to avoid oxidation, I eventually realized is that I was being way too careful!! I realized that oxygen is actually your red wine's best friend during primary fermentation. If you adjust your winemaking methods to include delestage or rack and return with good aeration, you can eliminate your burnt rubber off odors.

CHEERS AND GOOD LUCK!

Aaron

Hi David,

I think Paul and Aaron are on the right track with the diagnosis. If it is indeed mercaptans the fix is rather simple. Do a bench trial with copper sulfate. It usually doesn't take much at all. If you obtain 1% copper sulfate solution (most common in winemaking shops) then the maximum dose you'd want to use would be 0.6 ml's per gallon* . But again, I'd suggest bench trials and use the least amount that causes the odor to go away.

clyde

*this equates to 0.4 ppm of copper: an addition of 0.15 ml of 1% CuSO4 provides 0.1 ppm of copper

Paul, Aaron, and Clyde, Thanks for you responses. I had thought about mercaptans but had somewhat rejected it because I had no previous indications of H2S. But, I believe Aaron has zeroed in on the root cause...I have not done an adequate job of oxygenating the primary fermentation. I looked back at some old posts on mercaptans and plan a "test" using copper sulfate alone and ascorbic acid + copper sulfate to see if I can eliminate the odors. If it doesn't work...well, there is a vineyard full of grapes to get it right next year.

Again, thanks for your expertise.

Regards, David

Another additive they are selling now is Bocksin. I just used it for the first time and it definitely helped but is hasnt gone away completely. Perhaps it depends on the severity.