Did you know that if you leave flat beer in the fridge for long enough, it'll start fermenting again and get more alcoholic?
I've had some flat stout (or porter, don't remember) in a jar for a few months that I've been using to give a little umami kick to soup broths and such. Turns out it's been fermenting a little, as its gotten a tangier since the last time I used it. Which is all the better, because I made the BEST sauce with it last night: a bunch of the flat beer, barley miso, and sugar. I imagine a lighter miso would go well with a ligher beer for this (not sure how it would taste) but the dark, malty barley miso was perfect with the old stout.
Highly recommended to glaze fried eggplant with.
PS - points to whoever can tell me where this page's color palette came from!