Painting with Coffee by =Gold-Seven on deviantART - I've tied my hand at coffee painting before and it didn't go too well. But with something like this to refer to, I'm totally going to have another go!
Writing coffee with the "coffee cup stains" is nice. The original stain that makes the "C" was probably enlarged to create the "f", overlaid to create the "e". The nice brown color that remind us of real coffee stain.