An odor taint in the coffee brew marked by a loss of organic material that would normally be in a gaseous state in both the aroma and nose of the brew. Occurs during the staling process after the roasting or the holding process after brewing.
varietal distinction or character
If the coffee has characteristics that both set it off from other coffees, yet identify it as what it is, it has varietal distinction. In one sense, all of your three samples are distinctive, because they probably embody the best and most characteristic traits of the growing region from which they came. In another sense the Yemen Mocha and Sumatran could be seen as much more distinctive than the Mexican, simply because the Mexican embodies what for North Americans is a version of the normative coffee taste, whereas the other two coffees have characteristics that set them off from that norm. The rich, winey acidity of the Yemen Mocha immediately suggests that it is either a Yemen coffee or a good Ethiopian, for example; the heavy body and rich finish of the Sumatran identifies it as a good Indonesian coffee. It would be difficult to distinguish the Mexican coffee from a Peruvian, for example, or from any one of several other Latin American coffees.
A qualitative description of the gases and vapors present in the fragrance, aroma, nose and aftertaste of coffee's bouquet, which create a complex pattern of sensations of the olfactory membranes.