Percolated: fire burn and coffee bubble.
Edit on flat white from Wikipedia:
Derek Townsend, the co-owner of DKD café in Auckland, New Zealand, claims to have developed it, though acknowledges that the term “flat white” was already in use in Sydney to describe a similar style of coffee.
And from this dedicated coffee site about its origins and the probable reason for the term:
Coffee lovers say the term “flat white” emerged in cities such as Sydney and Wellington in the late 1980s and early 1990s. Where it originated is hotly debated.
Paul Bassett, a lead player in exporting Australian coffee techniques and styles to Japan and South Korea says that the ‘march of the Flat White’ is part of a backlash against cappuccino - people just don’t want all that foam any more.