Tasting the wine confirms our noses’ conclusions by increasing the wine’s temperature and evaluating two important physical and tactile factors: complexity and balance. Complexity is based on a wine’s aromatic richness and the length of its finish. Balance measures the interaction between a wine’s different flavors. The flavor of a wine refers to a combination of different tactile impressions that are desirable or undesirable in the mouth, primarily acidity, astringency and sugar content.

Acidity is very important, as it gives a wine depth. Without acidity, a wine is flat, uninteresting and has no aging potential. Excessive acidity renders a wine a bit aggressive or “green”, though there is no qualitative system of measurement for this. Acidity is perceived primarily on the sides of the tongue.

A wine’s smoothness compensates for and balances its acidity. This physical sensation can be regulated by alcohol, sugar or glycerol content. Wines from Southern France tend to be smoother than those from the North. This sensation is also expressed as roundness or viscosity. It describes the texture of wine and is perceived by the entire mouth, whereas sugar content is evaluated on the top of the tongue. A highly acidic wine can be very pleasant if it is sufficiently viscous, as is the case for Alsatian Rieslings.

Astringency refers to the wine’s roughness and describes the wine’s structure in the mouth. This sensation is produced by tannins, which can be more or less coarse. They block certain proteins in saliva and create a sensation of great dryness and roughness. However, there can be different types of tannins. Wines from the Médoc region have strong, but mature tannins provided by the Cabernet Sauvignon grape. They are the broad-shouldered athletes of the wine world. Red wines from Beaujolais, on the other hand, are less tannic and more delicate, as is characteristic of the Gamay variety. These are more feminine wines, but their slight acidity grants them a mischievous edge.

Balance between these three sensations creates the taster’s overall impression of the wine and is key in determining its pleasantness. Its aromatic complexity is a secondary factor, used to determine the difference between a good wine and an excellent wine.