Clean cup refers to a coffee free of taints and defects. It does not imply sanitary cleanliness, or that coffees that are not clean (which are dirty) are unsanitary. It refers to the flavors, specifically the absence of hard notes, fruity-fermenty flavors, earthyEarthy is a flavor term with some ambivalence, used positively in some cases, negatively in others.: Sumatra coffees can have a positive earthy flavor, sometimes described as "wet... ...more flavors or other off notes.
