Wine Glossary

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Acetic Acid- All wines contain acetic acid, or vinegar, but usually the amount is quite small--from 0.03 percent to 0.06 percent--and not perceptible to smell or taste. Once table wines reach 0.07 percent or above, a sweet-sour vinegary smell and taste becomes evident. At low levels, acetic acid can enhance the character of a wine, but at higher levels (over 0.1 percent), it can become the dominant flavor and is considered a major flaw. A related substance, ethyl acetate, contributes a nail polish-like smell.

Acid- A compound present in all grapes and an essential component of wine that preserves it, enlivens and shapes its flavors and helps prolong its aftertaste. There are four major kinds of acids found in wine: tartaric, malic, lactic and citric. Acid is identifiable by the crisp, sharp character it imparts to a wine.

Acidity- The acidity of a balanced dry table wine is in the range of 0.6 percent to 0.75 percent of the wine's volume. It is legal in some areas--such as Bordeaux and Burgundy, Australia, California--to correct deficient acidity by adding acid. When overdone, it leads to unusually sharp, acidic wines. However, it is illegal in Bordeaux and Burgundy to both chaptalize and acidify a wine.

Acrid- Describes a harsh or bitter taste or pungent smell that is due to excess sulfur.

Aeration- The process of letting a wine "breathe" in the open air, or swirling wine in a glass. It's debatable whether aerating bottled wines (mostly reds) improves their quality. Aeration can soften young, tannic wines; it can also fatigue older ones.

Aftertaste- The taste or flavors that linger in the mouth after the wine is tasted, spit or swallowed. The aftertaste or "finish" is the most important factor in judging a wine's character and quality. Great wines have rich, long, complex aftertastes.

Aggressive- Unpleasantly harsh in taste or texture, usually due to a high level of tannin or acid.

Alcohol- Ethyl alcohol, a chemical compound formed by the action of natural or added yeast on the sugar content of grapes during fermentation.

Alcohol By Volume- As required by law, wineries must state the alcohol level of a wine on its label. This is usually expressed as a numerical percentage of the volume. For table wines the law allows a 1.5 percent variation above or below the stated percentage as long as the alcohol does not exceed 14 percent. Thus, wineries may legally avoid revealing the actual alcohol content of their wines by labeling them as "table wine."

Alcoholic- Used to describe a wine that has too much alcohol for its body and weight, making it unbalanced. A wine with too much alcohol will taste uncharacteristically heavy or hot as a result. This quality is noticeable in aroma and aftertaste.

American Oak- Increasingly popular as an alternative to French oak for making barrels in which to age wine as quality improves and vintners learn how to treat the wood to meet their needs. Marked by strong vanilla, dill and cedar notes, it is used primarily for aging Cabernet, Merlot and Zinfandel, for which it is the preferred oak. It's less desirable, although used occasionally, for Chardonnay or Pinot Noir. Many California and Australia wineries use American oak, yet claim to use French oak because of its more prestigious image. American oak barrels sell in the $250 range, compared to more than $500 for the French ones. See also French oak.

Ampelography- The study of grape varieties.

Appearance- Refers to a wine's clarity, not color.

Appellation D'origine Controlee (AOC)- The French system of appellations, begun in the 1930s and considered the wine world's prototype. To carry an appellation in this system, a wine must follow rules describing the area the grapes are grown in, the varieties used, the ripeness, the alcoholic strength, the vineyard yields and the methods used in growing the grapes and making the wine.

Aroma- Traditionally defined as the smell that wine acquires from the grapes and from fermentation. Now it more commonly means the wine's total smell, including changes that resulted from oak aging or that occurred in the bottle--good or bad. "Bouquet" has a similar meaning.