Zach Dyer is a writer living in Saint Louis. He did his thesis research on coffee farmers in Southern Mexico. Since then, he has visited coffee plantations in Costa Rica and Mexico as well as roasters and cafés across the U.S. He blogs about coffee for Gut Check every Wednesday.Last September, McDonald's started airing an ad in which bespectacled hipsters drink coffee in a Starbucks-inspired setting. Upon hearing that McDonald's now serves cappuccinos, the characters spontaneously admit -- oh,