No matter how much fancy equipment we invest in to brew coffee at home (Chemex! Burr grinder! Fancy pour-over kettle thingy!), the iced dirty chai lattes that we pick up at our local coffee shop still always seem to taste just a little bit better. While it could be a figment of our under-caffeinated imagination, there's no denying the fact that professional coffee brewers do know best—which is why we asked a roast master and brewing expert technologist why coffee shop coffee is always a step above our own.