I just dumped a full keg that had a nasty phenolic taste. The beer (APA) was beautiful, crystal clear, nice head, good mouthfeel and absolutely awful. I had two kegs from the same batch and the other was fine.
This is the second time it has happened in 150 brews or so. I’m fanatic about sanitation so have no clue where it came from. It was saved yeast, only second generation. BRY 97.
Ideas?
Just a swag: maybe chlorine in your water? I’ve read chlorine reacts with yeast-derived phenols to create chlorophenols, which come across the palate as plastic-like or reminiscent of adhesive bandages.
If chlorine, the remedy is said to be switch to bottled water or simply allow your tap water to sit overnight: The chlorine will naturally diffuse into the air, and you’ll be ready to brew the next day.
Since the other keg was fine, and assuming you used the same flask (or whatever container) of harvested yeast for the good keg, then there’s a 99.999% likelihood it’s a wild-yeast infection within the keg.
I used to randomly get a latex-ish phenolic about once every other year. Since switching to iodophor for everything down stream of the fermenter it has not come back.
+1
Here is a quote from the “Off Flavors” section of the Beer Judge app:
“Wild yeast contamination can harbor within plastic-based equipment, such as polyethylene fermenters and plastic hoses. These materials as soft and permeable, hence difficult to clean. Wild yeasts such as S. diatatius produce minor wort phenols that impart medicinal off-flavors. Migration to glass and stainless replacements are the best solution…”
I’m wondering if you had an issue with your hoses and the contamination got cleared out while filling the first Keg and the hose was cleaned before the second keg was filled. Just a thought.
What was in the keg before this batch of beer? My guess is something was left behind or the keg wasn’t the cleanest it could have been. I don’t see how it can be water chemistry if you have the same beer in another keg and that beer is fine.
When’s the last time you cleaned out your taps and tap lines? Maybe something in there.