Infection killing my hop aroma?

[landon976]

I brewed a big IPA with a ton of dry hops. It was in primary for two weeks before I dry hopped at around 70 F for 5 days. I kegged the beer and it tasted great with big hop aroma. About a week later the aroma was gone and the beer was noticebly less hoppy in taste and had a subtle sour note. My question.. could an infection passed from a autosiphon kill my aroma? Has anyone ever noticed anyhtin similar?

 

[theredben]

Losing hop aroma over time is normal. Fresh beer is best when it comes to hops.

The sour you are tasting may just be off-flavour such as acetaldehyde (green apple tasting) that was produced during fermentation and was covered up by massive amounts of hops. As the hops subside the rest of the flavour profile becomes more apparent. What was your fermentation temp/schedule?

 

[landon976]

Pitched a 1 liter of WLP007 starter at 62F. Fermented at 64F until high krausen when I raised it 1 degree a day to 68F. It stayed at 68F until I dry hopped it around 70F.
Tasted good out of the fermenter, cold crashed, kegged and force carbed 12 PSI at 43F. Had great citrus aroma out of the keg before it was fully carbonated. Literally days later the hop aroma is gone. My wife describes the aroma now as wet dish towel.

 

[Maltose]

Maybe some oxidation from racking? "Wet cardboard" is a classic aroma/flavor of oxidized beer.

 

[landon976]

I have noticed some oxidation in a few of my beers before but that usually showed up later and not so dramatic that it would overpower my dry hops. I did forget to purge the keg with CO2 before I racked to it though.

I talked to a local pro brewer and he said the dish towel smell could be mercaptan. Also characterized as drain/rotting vegeies. The dish towel smell is very faint when the beer warms up. I'll see what develops.

 

[theredben]

Yeah, oxidation would not be an issue for a few months still. Does the beer taste good overall?