I'm not a "molecular gastronomist" but I did stay at a Holiday Inn last night:
Most of taste is actually smell. We only have a few taste buds--salt, sweet, sour, bitter, um..."yummy" (if you are Japanese, I hear).
However, we can distinguish hundreds if not thousands of smells. Something like a steak probably releases lots of aromas from protein and fat breakdown. If it were too cool, the fat and other liquids might also congeal, not only trapping aromas, but also presenting a less palatable texture.
I'm pretty sure old coffee suffers the problem of molecules breaking down if it is constantly heated after being made.
