ACIDITY is the natural tartness of grapes, giving a refreshing quality and preventing blandness. It is one of the main components in the structure of wine. The most common acids are tartaric, malic, lactic and citric.

ALCOHOL LEVEL is the amount of alcohol by volume. Wine generally ranges from 7 to 14% , with an average of 11 to 12%; fortified wines may reach 21%. By contrast, beer averages between 4 and 5%, and spirits generally start at 40%.

APPELATION is a geographical designation of origin. The system used in the States defines AVAs (or American Viticultural Areas). Acronyms for systems used elsewhere include AC and AOC (France); DOC and DOCG (Italy); DO and DOC (Spain); DO and IPR (Portugal).

AROMA is the combination of primary scents that evolves into bouquet as wine ages.

ASTRINGENCY is mainly associated with red wines, due to levels of tanin; it is experienced on the palate as a rough, drying sensation.

BALANCE is the harmonious interplay of components in a wine. For example, acidity balances sweetness; fruit balances oak; alcohol balances flavor.

BARREL AGING refers to keeping wine in a wooden barrel after fermentation and before bottling. Wood is porous and allows the wine to mature in controlled interaction with its environment; the wood may also provide flavor.

BARREL-FERMENTING means wines that are fermented in wooden (typically oak) barrels rather tha stainless steel tanks or other vessels.

BARRIQUE is a small (59 gallon) barrel for aging wine.

BLANC DE BLANCS is white wine made from white grapes.

BLANC DE NOIRS is whie wine made from red grapes.

BODY is the tactile impression of weight or fullness of wine on the palate.

BOTRYTIS causes grapes to rot, sometimes to delicious effect. The fungus botrytis cinerea attacks ripe grapes, particularly in humid vineyards, causing them to shrivel and become concentrated and sweet. The juice of grapes affected with this "noble rot" is used to make some of the world's great sweet wines, including Sauternes.

BOUQUET is the complex of fragrences that develops in a wine as it matures.

CARBONIC MACERATION is the fermentation of whole rather than crused grapes, resulting in light, fruity wines.

CAVA is the Catalàn word for cellar, and refers to sparkling wines made in Spain.

CÉPAGE is French for vine variety.

CLIMATE is a critical influence on the production of wine grapes. Climate includes the level of heat, sunshine, rainfall and wind. Each grape variety has specific conditions of climate which suit it best.

CORKED refers to a wine that has been tainted by a chemical compound in its cork, generally smelling of mold and must. Increasingly troubled by the problem of spoiled wine, the wine industry all over the world has been experimenting with alternative forms of bottle closures including synthetic corks and screwtops.

CRÉMANT is a term used to describe French sparkling wines made outside of the Champagne region, but employing the methode Champenoise in their production. Crémants are produced throughout France, most notabley in Alsace and the Loire.

CRU is the French term for rank or level, (often translated as "growth"), used to define a hierarchy of vineyards withn appelations. In most Bordeaux classifications, premier cru classé is the top rank. In Burgundy, peremier cru vineyards are one level below grand cru.

CUVÉE is a blend of wines.

DECANTING is gently pouring wine from the bottle into another container to enhance aeration and permit removal of sediment.

DRY describes a lack of perceptible sweetness. In dry wines, all or most of the sugar is fermented into alcohol. Brut is a French term for dry Champagne; extra-dry sparkling wines are actually sweeter than brut; demi-sec refers to a medium-sweet to sweet wine. Trocken is the German word for dry; halbtrocken is half-dry. Secco is Italian for dry, abboccato for slightly sweet.

FAT describes a full-bodied wine, where the level of acidity is lower than the perceptible sweetness or alcohol.

FERMENTATION is the process during which yeast transforms the sugar of grape juice (or mash of grains) into alcohol.

FILTERING is often used to remove yeast cells and other particles from wine after fermentation or prior to bottling.

FINNING is the removal of suspended particles, which cloud a wine, by introducing an agent - varying from powdered clay to egg whites - which binds to the suspended elements, making them heavy enough to fall to the bottom of the storage vessel.

FINISH is the wine's tactile and flavor impression left in the mouth after swallowing. In the finest wines, the finish should be long and lingering.

FORTIFIED connotes the addition of spirits to wine; to raise the level of alcohol, or to stop fermentation and therby maintain the natural sweetness of the grapes.

GLYCERIN is a by-product of fermentation most noticeable in higher alcohol and late-harvest wines, giving a smooth tactile impression.

KABINETT, SPÄTLESE & AUSLESE are German terms which signify, in ascending order, sugar levels at harvest, not the sweetness of the finished wine.

LATE-HARVEST refers to sweet wines made from extra-ripe grapes.

LENGTH describes wine with a prologned flavor and feel in the mouth.

LEES are the sediments - dead yeast cells, grape pulp, seeds and pigment - that drop to the bottom of a vessel during and after a wine's fermentation. Sur lie is a French phrase with refers to extended contact of wine with the lees, which imparts additional flavor (described in wine jargon as leesy).

MACERATION is the steeping of graped skins and seeds within the must to extract phenolics.

MALOLACTIC FERMENTATION is a secondary fermentation allowed to occur in some white wines and the majority of reds. This process is used to convert sharp malic acid into softer lactic acid. It contributes complexity and softness to most reds; in whites it imparts a buttery quality.

MERITAGE is a term for white or red wines from a California winery that incorporate a blend of varieties traditionally used in Bordeaux, France.

MÉTHODE CHAMPENOISE is French for "Champagne method," referring to the production of sparkling wines both in Champagne and elsewhere. The key step in the méthode Champenoise is the inducement of a secondary fermentation inside the bottle, by adding a small amount of yeast and sugar to a base wine and re-corking the bottle, trapping carbon dioxide from the second fermentation to give the wine bubbles.

MUST is crushed grapes ready to be fermented, or in the process of fermenting.

NÉGOCIANT is the French word for merchant.

NOSE refers to the aroma of a wine, or to the act of smelling the wine.

OXIDIZED describes wines that have spoiled or become brown due to oxygen.

PHENOLICS are chemical compounds found in wines; they include tannins, color pigments and flavor compounds.

RESERVA in Spain and Riserva in Italy are legally defined terms describing the aging requirements of wines in particular regions. In most other countries, "reserve" designations do not have legal definitions; they may refer to a selection or lot, or simply be part of a brand name.

RESIDUAL SUGAR refers to a percentage of natural sugars left in a finished wine. It is usaually expressed as a percentage of grams of sugars per liter of finished wine. A higher percentageof RS generally implies a sweeter-tasting wine.

STRUCTURE refers to the interaction of components which contribute to a wine's tactile sensation, icluding acidity, glycerin, alcohol and tannin.

SULFITES are a derivative of the element sulfur, widely used in winemaking, though most wineries keep thier applications to a minimum. Sulfur may be sprayed in the vineyard as a preventative agaisnt diseases, pests, and mildew. Sulfites may be used in the winery to clean and sterilize equipment, to kill off bacteria that could harm the wine, to prevent browining in the juice, to inhibit native yeasts on the grapes, or to guard against spoilage at bottling. Sulfites are also a natural by-product of fermentation, and most wines contain very low levels of added sulfites. By law, any wine with sulfites higher than 10 ppm must state "contains sulfites" on the label.

TANNINS are phenolic compounds derived primarily from grape seeds and skins, as well as the wooden casks in which wines are aged. Depending on the ripeness and quality of the grapes from which they are extracted, tannins can provide either a smooth texture or an astringency to the wine. Tannins impede oxidation and are a primary component in a wine's structure. As a wine ages, tannin becomes less noticeable as tannin molecules combine into large polyphnols and drop out as sediment at the bottom of the bottle.

TERROIR describes the enironment of a particular vineyard, including elements of soil, climate and aspect. The French term gout de terroir refers to the characteristic expression of a specific vineyard in a wine.

VARIETAL CHARACTER refers to the combination of aromas and tactile impressions typically offered by a particular grape variety.

VINTAGE is the year in which the grapes were picked, and also refers to the picking process.

VITIS VINIFERA is the genus and species of grapevine responsible for producing grapes that make the world's best wines - cabernet sauvignon, chardonnay, pinot noir, riesling, sauvignon blanc, etc.

YEASTS are one-celled organisms that, in winemaking, convert sugars into alcohol.

YIELD is the quantity of grapes or wine produced in a given area - often stated as tons/acre or hectoliters/hectare (hl/ha).