I know this might sound a bit weird but I believe someone else might have thought of the same thing.
Has anyone ever sniffed a cup of coffee after the coffee traces had dried up? I leave the cups on my desk and sometimes they stay there for hours on a busy day. In the evening I would sniff the cup and I am always amazed by how nicely it smells, sweet, chocolaty, etc. I was even inclined on doing an experiment to see whether a bad coffee shot would have a more bitter smell, this way one can figure out whether the bitterness is due to the more oily stuff (which most likely is the case) or the more volatile components (which in my book are the goodies). If the former the smell would reflect the presence of oily material that doesn’t evaporate quickly.
I have even gone that far wondering why the big perfume houses, e.g. Givaudan, Firminich, IFF, etc have not looked at this. Tobacco is widely used in Home fragrances but not coffee. I find this unfair 🙂
It would be interesting to know what the fellow coffee connoisseurs think about this.