Weird Smell, anyone have experience with this?

So, my American stout is about 2 weeks into fermentation. The other day i went to make a small initial addition of 1 oz coffee beans, 1 oz, cacao nibs, and a vanilla bean. When i took the rubber stopper out of the carboy, i picked up an odd almost rubbery or plastic smell. The stopper i was using was a standard offwhite almost yellowish stopper. I smelled the rubber stopper and it smelled strongly of what i was picking up in my beer. i immediately closed the carboy and ran down to by local home brew shop and grabbed one of the pure white stoppers that i am using in my IPA. The smell coming from the beer is seeming to dissipate day by day. My question is could this have been from the stopper? is this a smell coming from the yeast in early fermentation? should this completely vanish when the beer starts to condition a bit more? I plan on leaving it in there for another 2 weeks before kegging it and leaving the keg an additional week. A week before the keg i have another larger addition of the same ingredients so that may help bring the flavor up as well. thoughts?

 

Ive never heard of a stopper causing off flavors. Could it just be a rubbery smell from a new stopper that made the glass around the mouth which was in contact with smell similar?

 

I highly doubt your beer would pick up aromas or flavors from a rubber stopper. Fermentation is a funky beautiful thing that sometimes can smell wonderfully delicious or sometimes can smell like a gangrenous wound. Relax, let it ride out and do its thing. make your judgement when the beer is finished, carbed, and conditioned.

 

I don't know, this stopper STUNK and the entire inside of the carboy smelled exactly like it. Now that I've swapped it out, the smell seems to be going away but it just generally seems to be balancing out all together. I think you're right, fermentation just produces some weird smells sometimes.

 

Yeah, you were probably smelling the stopper, not the beer. If the stopper wasn't touching beer, it's not imparting any flavors to the beer. You're good.

 

Herpes. Definitely herpes.


Could be the yeast and some stinky fermentation too... but I'd put my money on herpes.

 

I second herpes

Whenever you're in doubt, taste the beer too.