The use of wine tasting descriptors allows the taster to qualitatively relate the aromas and flavors that the taster experiences and can be used in assessing the overall quality of wine. Wine writers, like Karen MacNeil author of The Wine Bible, differentiate wine tasters from casual enthusiasts; tasters attempt to give an objective description of the wine’s taste (often taking a systematic approach to tasting), casual enthusiasts appreciate wine but pause their examination sooner than tasters. The primary source of a person’s ability to taste wine is derived from his or her olfactory senses. A taster’s own personal experiences play a significant role in conceptualizing what he or she is tasting and attaching a description to that perception. The individual nature of tasting means that descriptors may be perceived differently among various tasters.
When tasting wine, individual flavors may also be detected, due to the complex mix of organic molecules (e.g. esters and terpenes) that grape juice and wine can contain. Experienced tasters can distinguish between flavors characteristic of a specific grape and flavors that result from other factors in winemaking. Typical intentional flavor elements in wine—chocolate, vanilla, or coffee—are those imparted by aging in oak casks rather than the grape itself.Vertical and horizontal tasting involves a range of vintages within the same grape and vineyard, or the latter in which there is one vintage from multiple vineyards.