Acidity: The sour or tart taste in wine and other food. The primary natural acid in grapes and wine is Tartaric acid; the second most abundant is Malic acid. Sometimes referred to as the "backbone" of a wine, acidity contributes to a wine's aging ability. The sour taste of acidity in wine is often pleasantly counterbalanced by sweetness (from sugar or alcohol).

Aftertaste: The "shadow taste" remaining in your mouth just after swallowing a sip of wine. Important in wine tasting because it can reveal an extra attribute or fault. In general terms the longer the taste lingers the better the wine.

Aging: Term describing the storing of wine under certain specific conditions for the purpose of improving the wine. Aging of wines (usually reds) for long periods in oak barrels adds oak-flavour and makes the wine more complex. After bottling, further aging in sealed bottles develops a pleasing taste and odour characteristic.

Alcohol: Many different compounds in nature are classed as "alcohols" chemically. In wine only one exists in significant amounts - ethanol. Other alcohols, if present, occur only in minute amounts and are usually thought of as flavour components. Alcohol adds a sweetish taste to wines, or hotness if present in too high a concentration. Conversely, if its alcohol content is too low, a wine may be thin, unbalanced and lacking in body.

Aligoté: A white wine grape used in various blends in many countries but best known for its fruity, light wines from Burgundy in France.

Amontillado: A type of Spanish sherry, medium in colour and sweetness between Fino (light and dry) and Olorosso (heavier and sweet). Amontillados are known for a distinctively nutty flavour not possessed by the other Sherry types.

Appellation Contrólée (AC/AOC): French wine laws that dictate which varieties can be planted in specific regions, certain production methods, etc. These tight controls are not a guarantee of quality, unfortunately.

Appellation: A term used to describe the vineyard location where the grapes were grown for a specific wine. It can refer to a broad region, such as Napa Valley in California or Bordeaux in France. Or, it can refer to a more tightly defined sub-region like Oak Knoll within Napa Valley or Médoc within Bordeaux. Wine snobs often proclaim that wines grown within certain highly regarded appellations have a higher quality than similar wines grown elsewhere. Experienced tasters know that this is not necessarily true.
All grapes, as all wines, grown within any certain appellation are not necessarily superb; neither are they necessarily plonk. Nevertheless, wines from certain appellations usually sell at higher prices than do similar wines from "lesser" appellations, regardless of how others might rank them.

Appley nose: A tasting term that describes an aroma in wine reminiscent of fresh apples. Most often this character is limited to white table wines.

Aroma: Smell or fragrance from wine that has its origin in the grape -- as opposed to "bouquet," which has its origin in the processing or aging methods connected to wine.

Assemblage: The blending together of component wine lots to form a final composite intended for bottling, for aging, for sparkling wine production or some other use by the winemaker. The word is also used to name the formal membership conclaves of the wine fraternity "Knights of the Vine."

Astringency: Sensation of taste, caused by tannins in wine, which is best described as mouth drying sensation, bitter or puckery.

Atmosphere: Unit of measure for pressure inside a bottle of Sparking Wine or Champagne. 1 Atmosphere equals 14.7 pounds per square inch (the standard atmospheric pressure at sea level in the world). Commercial sparkling wines commonly contain 4 to 6 atmospheres of CO2 pressure at room temperature.

Auslese: German word meaning "selection." In German wine law, auslese has a specific meaning which requires that the wine be made only from selected bunches of grapes, riper than others.