Late one night I stopped at one of those 24-hour gas station mini-marts to get myself a fresh-brewed cup of coffee. When I picked up the pot, I could not help noticing that the brew was as black as asphalt and just about as thick.

"How old is this coffee?" I asked the woman who was standing behind the store counter.

She shrugged. "I don't know. I've only been working here two weeks."