Something interesting I noted is that this beer and a stout I brewed right after it both had detectable amounts of the same acrid bitter funky taste, though at different levels.
The lager much more so than the stout.
One commonality I noticed in the two beers was the use of some pretty old, and pretty stale Cascade hops. They were stored in a freezer, but the bag was not airtight, and they might have been at least a few years old.
Perhaps it's possible that hops can become freezer burnt, or so oxidized that they throw off some nasty harsh bitters, instead of the crisp clean tasty hop bitters we all know and love.
The 'imperial pilsner' got most of these stale hops, the stout got a little, and I haven't used them in any other beers, and I haven't detected this taste in my other beers.
Also, can anybody describe the taste of 'yeast bite?'
That was another theory, but I'm not sure what that tastes like, perhaps a bit like actively fermenting beer with more bitterness? Not really sure, but then again these beers weren't on the cake for all that super long so I doubt that would be much of a factor.
I just fermented out a porter with the same type of yeast as the stout, but it tastes freaking terrific. Thank god.
Edit: Another note on that tasty porter is that it was probably the first beer I pitched up to a proper rate according to the Mr Malty pitching calculator.
