First of all, Happy New Year to my fellow brewers.
I’ve been detecting a low-level vegetal-type taste in my last 6 or so beers. Not enough to cause me to dump them, but enough to bug me (most of my beer drinking friends haven’t noticed it). A couple judges at comps I entered this fall noticed it too, but just made notes like “you may have a slight infection in this beer; check your sanitation procedures.” It has gone thru a fresh start with my favorite lager yeast, so while at one point I thought it was maybe one bad batch of beer that infected my yeast and screwed up subsequent batches, now I’m not so sure.
For sanitation, I mix up Starsan with distilled water every 2-3 brews, so it is a max of about 6 weeks old, and never cloudy when I use it. I have a stainless steel boil kettle with copper IC but a plastic run-off tube (but I chill with a big IC so only chilled wort is going thru the run-off tube into fermenters.) My fermenters are 7-gal plastic tanks about 5 years old. Is it possible they harbor something? I soak in hot PBW solution overnight after every fermentation though… or is it time to replace them?
I don’t think this is DMS because for all my pilsner-malt based beers I boil 90 minutes, and for all of them I chill quite rapidly (I can chill 10 gal of down to 60F in 10 min, on average). So I’m wondering if there a bugs that survive Starsan? Is there such a thing as a low-level beer infection vs. a "really bad" infection? Or does anyone have suggestions?
One other thing I was thinking: I buy my hops by the pound, and vacuum pack them in plastic vac seal bags when I open the pound. I keep them in an industrial walk-in freezer at work at -15F. Some varieties are 18 months old when I finally finish the pound. Any chance these old hops are possibly causing my problem?
Any help would be appreciated…