American Viticultural Area: an officially designated grape-growing region in the United States. In general, when AVA is stated on the label, at least 85% of the grapes must have originated in that AVA.

The aging that takes place in the bottle at the winery or after a wine has been purchased. Some wines benefit from and even require extended aging, while others may be at or near their peak shortly after bottling.

A measurement, expressed in degrees, of the solutes in ripe grapes, of which about 90 percent are sugars. One degree Brix corresponds to about 18 g/l sugar.

A box that holds bottles of wine, usually containing twelve 750-millilter (25.4-ounce) bottles.

A wine label designation that usually means the wine was purchased ready-made and then stored and bottled by a designated winery or wine merchant.

American term for the grape harvest, named after the crushing which occurs in the winery, as grapes begin being processed into wine.

The process of pouring wine from the bottle into another container. This may be done to separate an older wine from its sediment. Some people believe this process aerates wine and is beneficial for a young wine.

Descriptive term for wines with little or no noticeable sugar. Dry wines often have less than 2 g/l residual sugar, but may have more than 10 g/l when they have high acidity that offsets the sweetness. Almost all red wines are dry, while white wines range from bone dry to sweet.

The study or science of wine and wine making.

An American designation which a winery may place on the label if the wine is labeled with a viticultural area appellation of origin and the bottling winery is located in the labeled, viticultural area; grew all the grapes on land it owns or controls, within the viticultural area; and crushed the grapes, produced, and bottled the wine. This designation is similar to the European Chateau-Bottled and Domaine-Bottled designations.

The process of converting sugar to ethanol (ethyl alcohol) and carbon dioxide brought about by the anaerobic (oxygen-free) metabolism of yeast. Fermentation ceases when the sugars are depleted or the alcohol level reaches about 15%.

Unfermented juice or mixture of juice, pulp, skin, and seeds from fruit, berries, or grapes. The fermentation of must produces wine.

An American term used on the label if the bottler has produced at least 75% of the wine in the bottle.

The quantity of natural grape sugar remaining unfermented in the finished wine. Measured in grams of total sugars per liter, residual sugar usually ranges between 1 g/l and 25 g/l. Wines with a RS less than 2 g/l are described as dry, although wines with much higher levels may taste dry because the sweetness is offset by high acidity or possibly by bitterness from tannins.

Organic compounds found in seeds, stems, and skins of grapes; and to a lesser extent in oak barrels used to age some wines. During wine production, prolonged contact with grape skin, seeds, and stems results in higher levels of tannins. White and rosé wines are produced by minimizing this contact, and so their tannin levels are lower that that of red wines. Tannins produce a bitter taste and the tactile drying sensation of astringency, which may be encountered with young red wines that were designed for prolonged bottle aging, or with white wines produced with excessive skin contact. During aging, tannins are naturally removed from wine, as they polymerize and precipitate out as sediment.

A varietal wine is made completely or predominantly from a single grape type, and is named after the name of the grape.

The science and practice of the production of grapes.