Well that was quick;
"Freshly manufactured, authentic Pilsner-type beer samples (A−J), bottled in brown glass, were obtained from the German brewing industry. These samples were analyzed before (A0−J0) and after storage under forced aging conditions for 8 months at 28 C (A8−J8). In another set of experiments, samples of Pilsner-type beer D were kept in brown glass bottles in the dark for 8 months at 28 C, for 4 years at 20 C, and for 10 years at about 20 C, respectively. Another beer sample was stored for 4 years at 20 C in a polyethylene terephthalate (PET) bottle. Samples of beer D, bottled in brown glass, were kept under forced aging conditions for up to 582 days at 28 C in the dark prior to opening."
So I'm guessing that the Imperial Stouts and Barleywines in my "cellar" might be ok. Better get rid of that 4 year old Bitberger I've been saving though...