Acetic Unless wine is protected from the oxygen in the air its bacteria will rapidly produce volatile acetic acid, giving it a faint taste and smell of vinegar.

Acidity Don't knock it. At least half dozen different acids are essential for zest, freshness, liveliness, aroma, longevity - the best wines have plenty of acid balanced by plenty of stuffing. You taste too much acid in poor wines because stuffing is missing.

Aftertaste The flavor that lingers in you mouth after a sip. Scarcely noticeable (and occasionally unpleasant) in a poor wine; deliciously haunting in a great one. (See caudalie).

Age Not necessarily a good thing. Cheap wines in general want drinking young.

Alcohol Between 7% and 25% of a wine is alcohol, with most tables wines in the range 10 1/2-13 1/2%. During fermentation all or some of the sugar in the grapes is converted into ethyl alcohol, which acts as a preservative and gives the wine its 'vinosity', or winey-ness.

Amontillado A mature fino sherry, naturally dry but generally sweetened to be mellow in taste.

Appellation d'origine contrôlée (AOC) Official rank of all the best French wines, meaning 'controlled designation of origin', usually shortened to 'Appellation contrôlée' (AC). On a label, this guarantees both place of origin and a certain standard.

Aroma The primary smell of a young wine, compounded of grape juice, fermentation and (sometimes) the oak of a barrel.

Astringent Dry quality, causing the mouth to pucker - the result of high tannin or acid content.

Auslese German for 'selection'. Refers to a category of QmP (qv) white wine made of grapes selected for ripeness above a statutory level, depending on the region. A good Auslese benefits from aging for several years in bottle.