A little bit of coffee history for you: Way before Duane Sorenson, there was another mustachioed coffee guru. His name was Juan Valdez. And look who made an appearance at the premiere of the “Discover Colombia Through Its Heart” exhibit in Grand Central! (And here you thought Obama was yesterday’s most enthralling out-of-town visitor.) One of the exhibit’s heart-shaped sculptures apparently doubles as a café doling out free Colombian coffee. Or as we’ve seen it spelled on some local coffee carts, Columbian coffee. Juan Valdez would not be pleased.