Acidity: Grapes contain several acids, but the main ones are tartaric and malic. A little acidity in wine gives it a ”fresh” taste, but too much will make the wine ”tart” or ”sour.”

Aftertaste: The taste that remains in the mouth just after swallowing a sip of wine.

Air Lock: A device that allows fermentation gasses to pass out of the fermenter while preventing outside air from entering.

Aging: The storing of wine. Aging of wines in bottles, in some instances, improves taste and aroma. Long periods of aging red wines in oak barrels can add to its complexity.

Alcohol: Ethyl alcohol, or ethanol, is the only type of alcohol present in wine (in significant amounts). If a wine contains too much alcohol, it may impart a “hot” taste, whereas too little may leave a wine lacking in body, or unbalanced.

American Viticultural Area (AVA): A geographic area designated by the TTB and characterized by that area’s topography, soil, microclimate, and historical precedent.

American Wine: Any wine produced in any state from grapes grown in that state or in any other state(s).

Ampelography: (am-peh-LAW-gra-fee) A book that describes the structural characteristics of various varieties of grapevines.

Amphora: (AM-fuhr-uh) An ancient vessel used to store and transport wine.

Anther: The male (pollen-producing) part of the grape flower.

Aperitif: (ah-pehr-uh-TEEF) Any wine served before a meal. Traditionally, aperitifs were vermouths and other similar wines flavored with herbs and spices.

Appearance: A term used to describe whether a wine is crystal clear (brilliant), cloudy or contains sediment.

Appellation: (ap-puh-LAY-shuhn) Term used to define the vineyard location where the grapes were grown for a specific wine. A wine whose label states “Napa County” (the appellation) must have been made at least 85 percent from grapes that were grown in Napa County.

Argols: Name was given to raw cream of tartar crystals found in chunks adhering to the sides and bottoms of wine tanks.

Aroma: Smell or fragrance from the wine which has its origin in the grape – as opposed to “bouquet,” which has its origin in the processing or aging methods.

Assemblage: (ah-sahm-BLAHJ) 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.

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

Atmosphere: Unit of measure for pressure inside a bottle of sparkling wine or Champagne. One atmosphere equals 14.7 pounds per square inch and this is 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.

Aurore: Hybrid grape variety produced in the 19th century by French nurseryman Albert Seibel and still used, especially in the eastern U.S. for sparkling wine production. Sometimes spelled aurora.

Auslese: (OWS-lay-zuh) German word meaning “selection.” In German wine law, it means the wine is made only from specially selected, perfectly ripened bunches of grapes that are hand-picked.

Autolysis: (aw-TAHL-uh-sihss) The decomposition of dead yeast cells that occurs in wines that are aged “sur lie” (on the lees).

Axil: See leaf axil.

Bacchus: 1- Roman god of wine. Not to be confused with Dionysus, who was the Greek god of wine before the age of Rome. 2- A German white wine grape.

Baco Blanc & Baco Noir: (BAH-koh BLAHNGK & NWAHR) French hybrid wine varieties.

Baking: In wine, this term refers to the process of producing “Sherry” by deliberately oxidizing a wine through heating and aerating it for a period of several weeks. It is not uncommon for the process to take place over a 4 to 67 week period at 135 degrees F (57 degrees C).

Balance: 1– A subjective term used in wine evaluation. Wine in which the tastes of acid, sugar, tannin, alcohol, and flavor are in harmony is said to be in balance. 2– In the vineyard, it’s the relationship between grape clusters and shoot growth, and is controlled by proper pruning practices.

Balling: The name of a density scale for measuring sugar content in water-based solutions. Grape juice is primarily sugar and water and the balling scale is used for a quick and easy “sugar analysis” of juice. Balling and Brix often are used interchangeably. Each degree Balling is equivalent to 1 percent of sugar in the juice. For example, grape juice which measures 21 degrees on the Balling or Brix scale contains about 21% sugar.

Barbera: (bar-BEH-rah) Italian red wine grape.

Barrel fermenting: The act of fermenting grape juice in wooden barrels, as opposed to neutral containers (stainless steel, glass, plastic.

Barreling down: The act of placing wine into barrels for aging.

Baume: (boh-MAY) A system for measuring the sugar content of grape juice by its density. Each degree Baume is equal to approximately 1.75% sugar in the juice.

Bead: Colloquial term referring to the bubbles which float on top of a fermenting wine or champagne in the glass.

Beerenauslese: (BAY-ruhn-OWS-lay-zuh) Literally, “berry selection” in German. Beerenauslese wines are made from grapes that are picked individually rather than a whole bunch at a time. All grapes on a cluster or “bunch” do not normally ripen at exactly the same rates. Berry selection allows the winemaker to make superb wine by ensuring that every grape berry is at optimum ripeness.

Bentonite: A natural clay that is used in fining (clearing) wines.

Berry: Common name given to an individual grape.

Berry set: The fixing of tiny, newly pollinated berries to the stem.

Bianco: (BYAHN-koh) The Italian word for ”white.”

Big: Subjective tasting term which refers to a rich, full-bodied wine.

Bitter: Subjective tasting term. Bitterness usually refers to tannin in wine and is sensed by taste buds along the sides of the tongue in the extreme rear.

Black rot: Fungus disease of grapevines.

Blanc de Blanc: A term referring to white wine made from white grapes.

Blanc de noir: A term referring to white wine made from red grapes.

Blending: Combining two or more wines for the purpose of adjusting the flavor, aroma, and other components to create a more desirable wine.

Bloom: 1-The grape flower, or blossom. Also the time of grape flowering. 2- The greyish, powdery film which occurs on grapes in the field, and which contains wild yeast and dust.

Body: A tasting term referring to viscosity, thickness, consistency, or texture. A wine with body often has higher alcohol or sugar content than others.

Bordeaux: (bohr-DOH) An area in southwest France considered by many to be one of the greatest wine-producing regions.

Bordeaux mixture: A mix of copper sulfate, lime, and water used as a spray-on grapevines to fight fungus diseases.

Botrytis: (boh-TRI-tihs) Fungus which grows on certain grapes as they ripen under certain weather conditions. Called “noble rot” because it concentrates both sugar and flavor.

Bouquet: Smell or fragrance in wine which has its origins in the wine production or aging methods.

Brandy: The liquor obtained from distillation of wine and aged in the wood.

Breathing: Letting a bottle of wine stand for several minutes to several hours after pulling the cork but before serving it.

Brilliant: Sensory evaluation term to describe a wine that is crystal clear and absolutely free from sediment or cloudiness.

Brix: (BRIHKS) The unit of measurement of soluble solids (sugar) in ripening grapes. A reading of one-degree brix equals one percent sugar in the juice.

Brut: French term referring to the driest (least sweet) Champagne. Drier than “extra dry.”

Bud: Small swelling on a shoot or cane from which a new shoot develops.

Bud break: The action of buds swelling and beginning new growth in spring.

Burgundy: Located in eastern France, it’s one of the most famous wine-growing areas.

Bung: The hole in a barrel (or tank).

Butt: A “large” wine barrel, usually just over 100 gallons in capacity. “Normal” barrel sizes are approximately 50 or 60 gallons in capacity.

Cabernet Franc: (KA-behr-nay FRAHNGK) A vinifera species of grape.

Cabernet Sauvignon: (KA-behr-nay soh-vihn-YOHN) A vinifera species of grape.

Calyptra: The covering of an emerging grape flower.

Cambium: Layer of living tissue under the bark and phloem tissue of a grape vine. New wood cells (xylem) form at the inside of cambium as it grows; new phloem and bark cells form at the outside edge. The net effect is to increase the diameter of the vine.

Campden tablets: See potassium metabisulphite.

Cane: The mature shoot of a vine.

Canopy: The leaves and shoots formed by a grapevine.

Cap stem: The small length of the stem which connects each individual grape berry to its bunch.

Cap: 1– A tiny green cover that loosens, then falls off exposing the pinhead-sized ovary and releasing the pollinating anthers of an individual grape flower. When the cap falls off, the flower is said to be in bloom. 2- The floating solids (skins and bits of the stem) in a tank of fermenting red wine. It binds together forming a thick mat that must be broken apart (at least once a day) during fermentation in order to extract the color and flavor of the skins and to prevent over-heating of the wine.

Capsule: The wrapping that covers the neck and cork of a wine bottle.

Carbon dioxide (CO2): A gas that occurs naturally in the air. Vine leaves produce sugar from CO2, sunlight, and water. This sugar is the source of energy used by the vine for growth and grape production.

Carbonic maceration: A process where wine grapes are not crushed but fermented whole. The process is used to make wines that are particularly light and fruity. This is the process commonly used to produce “nouveau” wines of the Beaujolais region of France.

Carboy: A glass bottle used (usually by home vintners) to ferment and wine. They range in size from 5 to 7 gallons.

Cask: Any wooden container used for wine aging or storage. The term includes barrels, butts, pipes, etc.

Catawba: (kuh-TAW-bah) An American hybrid wine grape grown in the eastern U.S. and Canada and produces sweet white, red, and rose’ wines that have the so-called ”foxy” aroma component.

Cayuga: (kay-YOO-guh) A French/American hybrid grape.

Cepage: (say-PAHZH) French for the grape variety.

Chablis: Wine region in central France named for the village near its center.

Chambourcin: (shahm-boor-SAN) A French/American hybrid grape.

Champagne: Sparkling wine produced in the Champagne region of France. Most US wine producers use the term “sparkling wine” and may indicate that it was made by the French ”methode champenoise.”

Chancellor: A French/American hybrid grape.

Chaptalization: The act of adding sugar to grape juice or must early in the fermentation to correct for natural deficiencies.

Character: A wine tasting term referring to the style of taste.

Chardonnay: (shar-doh-nay)A vinifera species of grape.

Charmat process: A process developed by Eugene Charmat for producing sparkling wine or champagne cheaply and in large quantities by conducting the secondary fermentation in large tanks rather than individual bottles.

Chianti: (kee-AHN-tee) Medium to full-bodied red table wine of Tuscany in Italy. Chiantis are blends, but the primary grape variety used is Sangiovese.

Chloroplasts: Oval, chlorophyll-bearing structures inside the cells of leaves that act as factories to produce sugar for plant growth from CO2 and water. The energy used for this conversion is sunlight, captured by chlorophyll.

CO2: See Carbon dioxide.

Claret: Common name for the red wines of Bordeaux.

Clarity: In wine evaluation, a subjective term for the absence of cloudiness or sediment in wine.

Clone: Grapevines descended from the same individual vine. One vine, found to have especially desirable characteristics, may be propagated by grafting or budding to produce a whole vineyard that is identical to the original vine.

Clos: In France, a walled or enclosed vineyard. The word is now used in other countries as part of a name for a winery or wine label.

Closed-top tanks: Fermentation tanks with permanent tops. These always have doors or vents in the top to facilitate cleaning and for monitoring fermentations.

Cloying: A tasting term meaning the wine is difficult to enjoy because of excessive sweetness which “stays in your mouth” after the wine is gone.

Cluster: A “bunch” of grapes.

Cluster thinning: The process of removing young grape clusters to control the size of the crop.

Coarse: A wine-tasting term referring to an unfinished, rough, or crude wine that is difficult to drink.

Cold stable: A wine that can be kept in a refrigerator without forming sediment or crystals is said to be cold stable.

Cold stabilization: Chilling wine to below 30 degrees F to precipitate potassium crystals out of solution.

Compound bud: The normal type of bud which appears at each node along with a vine shoot or cane. It contains not one but three separate, partially developed shoots with rudimentary leaves in greatly condensed form. Usually, only the middle one grows when the bud pushes out in the spring. The others break dormancy only if the primary shoot is damaged.

Concord: An American hybrid wine grape grown in the eastern and mid-western U.S. and Canada and produces sweet finished wines that have the so-called ”foxy” aroma component. Also used for grape juice and jellies.

Cooperage: Common term in general used to describe any container used for aging and storing wine. Cooperage includes barrels and tanks of all sizes.

Cordon: A French word (roughly translated means ”arm”) which refers to the permanent wood of (usually horizontal) a grapevine from which the fruiting wood is grown.

Cork: Cylinder-shaped piece cut from the thick bark of a cork-oak tree and used as a stopper in wine bottles. Cork is especially well suited for this purpose because of its waxy composition and springiness.

Corky: A corky wine has an unpleasant odor and flavor of moldy cork.

Corolla: An individual grape flower before it blossoms.

Cream of tartar: A natural component of grape juice and wine. The chemical name is potassium bi-tartrate. Removed from wine as a by-product, cream of tartar is used in cooking.

Cremant: A category of champagne that contains less carbonation than standard champagnes. Cremant champagnes are usually light and fruity.

Crisp: Tasting term to describe good acidity and pleasant taste without excessive sweetness.

Cru: French word for growth. It refers to a vineyard of especially high quality, such as a classified growth or “cru classe.”

Crush tank: Wine tank which receives the newly crushed must—pumped directly from the crusher.

Crush: The process of crushing and de-stemming wine grapes just prior to fermentation. “The crush” refers to the autumn season when grapes ripen and are fermented.

Crust: The sediment, often crystalline, which forms inside wine bottles during long bottle aging. It is often brittle and can break into pieces as the wine is being poured.

Cultivar: A cultivated variety of grapes.

Cuvaison: (koo-veh-ZOHN) The period of time when grape juice is kept in contact with the skins and seeds during fermentation.

Cuvee: (koo-VAY) A batch of wine usually held in a single tank or large cask. Cuvee often refers to a specific blend of still wines which was blended purposely for later champagne making.

De Chaunac: French/American hybrid wine grape named for a pioneer winemaker from eastern Canada.

Decant: Pouring wine carefully from a bottle in which loose sediment would otherwise become stirred up. After decanting, (carefully pour off the clear wine until only the sediment remains behind, the sediment can be washed out of the bottle. Then the decanted wine can be returned to the clean bottle for serving.

Degorgement (disgorging): Act of removing the frozen plug of ice (containing spent yeast) from a champagne bottle after the riddling. Degorgement takes place on the bottling line just prior to adding dosage and the final corking of the finished bottle of champagne. See dosage.

Delaware: An American hybrid wine grape is grown in the eastern U.S. and produces dry, sweet, and sparkling white wines with a barely perceptible “foxy” character. Also makes an excellent ”ice wine.”

Demi-sec: Champagne term signifying that the product is medium-sweet.

Dessert wine: Any of a class of sweet wines, usually fortified to higher alcohol content, which is served with desserts or as after-dinner drinks. Common dessert wines are Ports, Sherries, Muscatel, Madeira, Tokay, and Angelica.

Dionysus: Greek god of wine and revelry. See Bacchus.

Dosage: The few ounces of wine, often sweetened, which is added to each bottle of champagne after disgorging to make up for the liquid volume lost by disgorging.

Downy mildew: Fungal disease of grapevines which kills the affected tissue. The disease is native to eastern North America and has spread to Europe and most other regions of the world.

Dry: The complete absence of sugar in the wine.

Early harvest: These wines are produced in the coolest years when grape ripeness doesn’t achieve full maturity. The wines are low in alcohol, light, and easy to drink despite having high natural acidity. The German equivalent is trocken or halbtroken.

Earthy: Sensory evaluation term for wine with a taste or smell reminiscent of soil, mushrooms, or mustiness.

Egg white: Leftover albumin obtained by discarding the yolks from eggs. It is used in fining wines.

Enology: The science and technical study of winemaking.

Estate bottled: Label phrase (implying quality) meaning that the wine was produced and bottled at the winery from grapes owned (and farmed) by the winery owners.

Esters: Aromatic flavor compounds which give fruits, juices, and wines much of their “fruitiness.”

Ethanol (Ethyl alcohol): The type of alcohol produced by yeast fermentation of sugar under ordinary conditions. The alcohol in alcoholic beverages is always ethanol.

Fermentation: The process carried out by yeast growth in grape juice (or other sugar solutions) by which sugar is transformed into ethyl alcohol and CO2.

Fermented “on the skins”: Statement made about a wine (almost always red) which was fermented with the juice and solids together. The solids are discarded after the fermentation is completed.

Fermenters: Tanks, barrels, or other containers when used for fermentations.

Fining: The process of adding material to wine in order to clarify it.

Finish: The last impression left in the mouth by the taste of a wine.

Finishing: The last steps in processing a wine before bottling, and may include bottling. Often, this includes fining, blending and filtration, or centrifugation.

Fino: Term found on some sherry labels to denote the winery’s lightest and driest sherries.

Flabby: Tasting term for a wine that is too low in acidity, too high in pH, and difficult to drink.

Flat: Tasting term. Similar to flabby, a flat wine is lacking in acidity and crispness. Flat wines are difficult to drink and enjoy even if the flavor is good. In sparkling wines flat means the wine lacks carbonation.

Flinty: Tasting term used to describe wine with a hard, dry, clean taste reminiscent of flint struck by steel.

Flowery: Tasting term for wine with an exceptionally aromatic character reminiscent of fresh garden flowers.

Foch: See Marechal Foch.

Foxiness: Tasting term to describe the smell and taste of Concord grapes and wine, and the smell and taste of similar varieties of vitis labrusca.

Free-run juice: The juice which separates from must by draining alone (without pressing).

French/American Hybrids: Grape varieties that did not occur in nature but were produced by crossbreeding (usually crosses between one or more native American varieties and one or more European traditional wine varieties).

Fruitful bud: A bud that will grow into a fruit-bearing shoot.

Fruity: Tasting term for wine that has retained the fresh flavor of the grapes used in its fermentation.

Fume Blanc: A name that has come to be synonymous with Sauvignon Blanc table wine.

Gassy: Sensory evaluation term describing a wine that contains residual carbon dioxide left over from the fermentation.

Generic wine: Blended wine of ordinary quality, without any varietal or other special characteristics. Everyday, low price wine.

Green: A tasting term describing the grassy, herbaceous or vegetal taste of wines that were grown in too cool a climate.

Heartwood: The innermost portion of the woody tissue (xylem) making up the trunk of woody plants, such as grapevines or trees. Heartwood is composed of dead xylem cells which serve to give wood its strength.

Heat summation: A measure of the climate of a growing region calculated by adding the mean temperatures for each day (minus a base temperature) over a growing season. For grapes, the base temperature is 50 degrees F (10 C).

Hectare: Unit of size for farmland in France. One hectare is approximately 2.5 acres.

Hectoliter: Common unit of measure for wines in all European wineries. One hectoliter is 100 liters, 22.03 British imperial gallons or 26.42 U.S. gallons.

Herbaceousness: Refers to a vegetative taste in wine.

Hock: A term used to describe the unusually tall bottle which is used for Riesling and similar wines. Also, hock refers to Riesling and similar wines themselves.

Hot: Taste sensation often found in high alcohol wines.

Hybrid: In viticulture, a new variety results from crossing two other (often very different) varieties.

Hydrometer: An instrument used to measure the specific gravity of a liquid.

Ice wine: Wine made from frozen grapes. Ice wines are always sweet, usually light, and also delicate.

Internode: The section of a grapevine stem between two successive nodes or joints on the shoot or cane.

Jeroboam: Oversize wine bottle; however, the exact size is not standardized. It may be equivalent to 4, 5 or 6 standard (750 ml) bottles, depending upon the wine producer. In Champagne, France, and in California, it is often 3 liters in size; in Bordeaux, 3.75 liters; in England, as much as 4.5 liters.

Jug wines: Common name given to wines sold at modest prices in 1.5 liter size or larger containers.

Keg: Small barrel for wine aging or storage — usually 12-15 gallons in size.

Jeroboam: Oversize wine bottle; however, the exact size is not standardized. It may be equivalent to 4, 5, or 6 standards (750 ml) bottles, depending upon the wine producer. In Champagne, France, and in California, it is often 3 liters in size; in Bordeaux, 3.75 liters; in England, as much as 4.5 liters.

Jug wines: Common name given to wines sold at modest prices in 1.5-liter size or larger containers.

Keg: Small barrel for wine aging or storage — usually 12-15 gallons in size.

Labrusca: A principal species of native North American grapes. Concord is the purest example currently grown on a large scale in the eastern U.S.

Lactic acid: A natural organic acid that occurs in many foods. In wine, it exists only in trace amounts unless the wine has undergone malolactic secondary fermentation.

Lambrusco: Not to be confused with Labrusca. Produced in northern Italy, Lambruscos are sparkling red wines, usually sweet, light, fruity and pleasant to drink.

Late harvest: Name given to dessert or full-bodied table wines produced from overripe grapes.

Leaf axil: The acute angle between a vine shoot and a leaf stem or petiole extending from the shoot. Buds develop in these axils just above each leaf petiole.

Lees: The sediment which settles to the bottom of the wine in a tank during processing. If primarily yeast, as from fermentation, it is called “yeast lees”; if sediment from fining, it is called “fining lees.”

Legs: Term referring to the colorless droplets which form along the inside wall of a wine glass, just above the surface of the wine.

Limousin: A type of French oak used to make barrels. Its grain is less tight and more open than others, allowing the oak flavor to become extracted out of the wood quickly.

Maceration: The act of soaking grape solids in their juice for certain time periods prior to fermentation of the juice.

Madeira: Portuguese island in the Atlantic from which come rich, sherry-like dessert wines.

Maderization: Oxidation of table wines due to improper storage. Maderization gives Madeira wines part of their desirable character, but the same character is undesirable in normal table wines.

Magnum: Oversize bottle, twice the size of a standard 750 ml. wine bottle.

Malbec: One of the major red wine grape varieties of Bordeaux.

Malic acid: A natural organic acid that occurs in ripe grapes in relatively high concentrations. It is the second most abundant organic acid in most varieties.

Malolactic fermentation: A bacterial fermentation that sometimes occurs in new wines after the primary yeast fermentation. Malolactic, or secondary fermentation, changes natural malic acid into lactic acid and CO2.

Marechal Foch: A French-American hybrid wine grape is grown throughout the eastern U.S. It produces a somewhat light, yet deeply colored wine.

Medoc: Red wine district within the Bordeaux region of France.

Meristematic tissue: The growth tissue of a grapevine, located in the cambium, shoot tips, buds, root tips, and flowers. Meristematic tissue is composed of thin-walled actively growing cells which form new cells by dividing.

Merlot: (Mare-Low)A vinifera species of grape.

Methode champenoise: The traditional bottle-fermented method for producing sparkling wines, including hand riddling and disgorging.

Microclimate: The localized climate in a specific, small area as opposed to the overall climate of the larger, surrounding region. A microclimate can be very small, as to encompass a single vine, or cover a whole vineyard of several acres or more. Microclimates can be caused by the slope of the land, soil type and color, fog, exposure, wind, and possibly many other factors.

Mildew: Grapevine disease. Can be devastating but is usually controlled by dusting the vines with sulfur or spraying with organic fungicides.

Mineral ions: Electrically charged forms of minerals, usually occurring in the soil moisture and available for take-up by the roots. Some examples used by grapevines are potassium, calcium, phosphate, boron, nitrate, sulfate, iron, manganese, and magnesium.

Mission: The first of California’s line of wine grapes.

Muscatel: Wine made from Muscat grapes, usually sweet and usually high in alcohol.

Must: The liquid (mostly) portion of freshly crushed grapes (before fermentation). Includes pulp, skins, seeds, juice, and bits of stem.

Nebbiolo: A vinifera species of grape.

Nevers: One of the types of French oak used for wine barrels.

Niagara: An American hybrid wine grape grown in the eastern and mid-western U.S. Makes a fruity white wine with a strong ”grapey” flavor. Also a popular table grape.

Noble rot: Common name for Botrytis Cinerea, the famous fungus of more than a few fabulous dessert wines.

Nodes: Slight enlargements occurring at more or less regular intervals along the length of vine shoots and canes. One leaf develops at each of these nodes and a new bud forms in the axil at the node also.

Norton: An American hybrid wine grape grown in the southeast U.S. (especially Virginia). Makes a quality red wine with ”coffee” and ”spice-like” flavors.

Nose: The odor of wine, including aroma and bouquet.

Oaky: A term used to describe the oak flavor in a wine.

Oidium: French word for the fungal vine disease “powdery mildew.”

Open-top tanks: Wine tanks without permanent covers, used only for red wine fermentation.

Ordinaire: From “vin ordinaire,” the term means any common wine of everyday quality.

Overcropped: A vine that carries more crop than it can reasonably ripen. Vines that aren’t pruned drastically enough tend to set too much crop. The wine produced from the fruit of an overcropped vine is always poorer in quality than if the crop were normal size.

Overcropping: The act of allowing vines to set too much fruit (usually by pruning too lightly in winter).

Oxidation: Adverse change in wine flavor, stability, and/or color caused by excessive exposure to air.

Pasteur: Louis Pasteur, the father of modern winemaking and pasteurized milk. He correctly identified yeasts as the causative organisms for fermentation and developed a heat process (Pasteurization) for stabilizing wine, milk, and other liquid foods from spoilage.

Pectic enzyme: This natural product helps break down fruit and aids in juice extraction. It also prevents cloudy pectin hazes in wines.

Pedicel: Stem that attaches the individual grapes to the cluster (see Peduncle).

Peduncle: Stem that attaches the grape cluster to the shoot.

Petillant: Term describing a wine that is noticeably sparkling or bubbly with CO2 — but which is less carbonated than champagne.

Petiole: The stem which attaches a leaf to its main branch or shoot.

pH: Term that defines the acidity of juice and wine. It represents the concentration of hydrogen ions in a solution.

Phenolics: See polyphenols.

Phloem: Living plant tissue located just beneath the bark and outside of the cambium layer. Phloem cells conduct sugars and other organic materials downward from the leaves towards the trunk and roots.

Photosynthesis: The process by which sunlight is used by the green tissue of plants to convert CO2 into sugars.

Phylloxera: Microscopic aphid which lives on vine roots by sucking their juice. The aphid kills European wine varieties but native American vine roots are resistant.

Pinot: (PEE-noh) Family of grape varieties, notably Pinot Blanc, Pinot Gris, and Pinot Noir (NWAHR).

Polyphenols: Chemical class of compounds that occur naturally in wine, giving it an astringent, bitter, or mouth-drying taste sensation. Tannins and grape skin pigments are two prominent classes of polyphenols.

Pomace: The solid residue (primarily skins, seeds, and stems) left over after the juice is pressed out of the must.

Port: Any of the rich, sweet, alcoholic and full-bodied wines from the Oporto region of Portugal. Other countries also use the term for wines of similar type, but the original name is Portuguese.

Powdery mildew: Fungal disease of grapevines which, unlike most fungal diseases, thrives in dry climates.

Potassium carbonate: Chemical to lower the amount of total acid in wine. Used during winemaking.

Potassium sorbate: Used during winemaking, this chemical halts yeast reproduction, thus preventing renewed fermentation.

Potassium metabisulphite: A source of sulfur dioxide used during the winemaking process to inhibit wild yeast growth.

Precipitation: The sudden formation of solids within a solution, as happens in the fining of wines. The solids normally settle to the bottom as a sludge within a few hours or days and can be easily removed by filtration, centrifuging, or simply racking.

Press juice: The juice is obtained not by draining but by pressing fresh pomace. It is usually far more tannic (often bitter) than drained or lightly pressed (free run) juice.

Press wine: Wine obtained by pressing newly fermented red wine from spent pomace. It is invariably more tannic than free-run wine.

Press: The act of squeezing the last remaining drops of juice or wine from pomace. Also, the machinery used to do such a thing.

Proof: Scale for measuring and expressing the alcohol content of liquids. The “proof” of a liquor is twice its alcohol content, ie, 80 proof = 40% alcohol. Since wine is always much lower in alcohol than the range commonly used for proof, the term has no use in wine production or on wine labels.

Pruning: The act of cutting off various parts of grape vines, usually in winter when the vines are dormant. Pruning develops the shapes of vines when they are young and controls the growth, fruit quantity and quality of producing vines.

Pumping over: Act of pumping wine out from a bottom valve of a fermenting tank up onto the top of the fermenting mass in order to keep the solid “cap” of skins wet. This is necessary during the fermentation of red wine in order to achieve complete extraction of color and flavor from the skins.

Punching down: The act of pushing the cap down into the fermenting liquid to wet it and facilitate color and flavor extraction. This is the traditional method, but it can only be used for small tanks. Larger tanks are “pumped over.”

Punt: The concave indentation in the bottom of certain wine bottles, especially those containing sparkling wine. Its main purpose is to collect crystals or sediment (this only works if the bottle is standing upright) so that the wine may be decanted easily.

Pupitre: French name for the hinged, wooden “A-Frame” rack used for riddling champagne bottles prior to disgorging. (Riddling settles the yeast sediment into the neck so that it can be easily removed.)

Rachis: The skeleton of branched stems that gives a bunch or cluster its shape.

Racking: Decanting clear juice or wine from above the sediment in a tank. This is the easiest method for getting rid of solids that have settled to the bottom in a tank.

Reduced: Term describing a state which is the chemical opposite of oxidized. In wine, the reduced state is usually recognized by the smell of rotten eggs (hydrogen sulfide, or H2S).

Residual sugar: A term commonly used in wine analysis referring to the content of unfermented sugar in a wine already bottled.

Respiration: The process in which plants produce energy, water, and CO2 by the interaction of oxygen and sugars.

Rhine: Famous wine river in Germany. Name given to all German wines produced from vineyards near the Rhine river.

Rhone: Major river in southeastern France, flowing from Switzerland to the Mediterranean. Name given to the wines produced from vineyards along the river.

Riddling: The process which causes the yeast sediment in champagne bottles to settle into the neck so that it can be easily removed.

Riesling: (REEZ-ling) This grape variety is best known for being made into some of the world’s finest dessert wines. Susceptible to noble rot (Botrytis).

Rose: French word for pink wine, now commonly used all over the world.

Sack: Sixteenth-century name for sherry wine.

Sangiovese: (San-joh-VAY-zeh) A vinifera species of grape.

Sapwood: The outer portion of woody (xylem) tissue, located just inside the cambium and just outside the heartwood. Sapwood forms the primary highway for the transmission of water and minerals from the roots up through the vine.

Sauvignon Blanc: (Soh-vihn-yohn-blahngk): A vinifera species of grape.

Schloss: The German word for a castle; on a wine label it is equivalent to the French word “Chateau.”

Scion: The above-ground portion of a grafted vine.

Scuppernong: One of the two major classes of native American grapes.

Sec: French term meaning “dry.” However, on champagne labels it means that the wine is sweet.

Secondary fermentation: Fermentation happens after the primary (yeast) fermentation has been completed. Malolactic is a secondary fermentation that occurs in most red, and some white still wines. Another secondary is yeast fermentation which changes still wine into sparkling wine.

Sekt: The German word for sparkling wine.

Semillon: (say-mee-yohn): One of the primary white wine grapes of the Bordeaux area.

Set: See Berry set.

Seyval: A French/American hybrid grape.

Shatter: A term used to describe berries that fall from the bunch quite easily.

Shoot: The elongating, green, growing vine stem which holds leaves, tendrils, flower or fruit clusters, and developing buds.

Shot berries: A few small, seedless grapes found in an otherwise normal bunch of wine grapes.

SO2: See Sulfur dioxide.

Soave: A blended white wine is produced in northern Italy.

Sodium metabisulphite: Serves the same purpose as potassium metabisulphite.

Soft: A term for the taste of a wine that is low in acidity, flavor, body, and which tastes somewhat sweet.

Sommelier: (saw-muh-lyay): A “wine steward” or waiter in charge of wine.

Sour: The taste sensation of acid. Not to be confused with bitter, which is the taste of some tannins.

Spaetlese: German word meaning “late harvest.” These wines are usually sweet and high in quality.

Spicy: 1- Tasting term to describe a wine that tastes as if it had spices added during production. Gewurztraminer is the wine variety that is most often referred to as spicy. 2- Smell or taste sensation reminiscent of spices. The Gewurztraminer flavor is naturally spicy, especially when grown in cool climates.

Spumante: The Italian word for sparkling wine. Equivalent to sekt in German.

Spur: A shortened stub of cane, usually formed by pruning the cane to a length of only two to four nodes (buds). Spurs are obvious in the spring, after pruning but before new growth begins.

Stabilization: Any treatment or process which makes a wine stable, i.e., unlikely to suffer physical, chemical, or microbial change.

Stems: The rachis or skeletal remains of a grape bunch or cluster after the grapes have been removed.

Stigma: The female (pollen accepting) part of the grape flower.

Still wine: Wine that is not sparkling, i.e., does not contain significant carbon dioxide in solution.

Stomata: Tiny openings on the undersides of grape leaves that control transpiration.

Stuck fermentation: A fermentation that stops prematurely and refuses to start up again even though fermentable sugar still remains in the liquid.

Sugaring: Called “chaptalization” in France and most other countries, sugaring is the addition of common sugar to fermenting grape juice or must for the purpose of raising the eventual alcohol content in the wine. Illegal in some states, sugaring is usually needed only in very cool climates (or very cool vintages) in which the fruit fails to achieve full ripeness naturally.

Sulfite: The dissolved form of sulfur dioxide.

Sulfur dioxide: A pungent gas used in wine to inhibit wild yeast growth, to protect wine from air oxidation, and to inhibit browning in juice and wine.

Sur lies: French term meaning that the wine was held in contact with yeast lees longer than usual in aging and processing. The result is often a wine with a pleasant yeastiness and more complexity (though sometimes oxidized and bacterial) than ordinary wines.

Sweet pomace: Solid grape residue after the juice is drained off, but prior to fermentation. Primarily composed of skins, stems, and seeds.

TTB: The U.S. federal agency which collects alcohol taxes and administers wine regulations.

Table wine: Legally defined category of wine which includes all wines with an alcohol content that is lower than 14%.

Tannin: Natural polyphenolic material which has a bitter or astringent taste, making the mouth pucker. Tannin in wine comes from grape skins, stems, seeds, and wood contact during barrel aging.

Tart: Acidic (used as a pleasant descriptor in wine tasting).

Tartaric acid: The most prominent natural acid of grapes, juice, or wine.

Tastevin: (tahst-vahn): A shallow silver (sometimes gold) wine tasting cup used by sommeliers in restaurants.

Tendrils: String-like, coiling growth from nodes of grape shoots that support vines by curling around objects.

Terroir: Terrain (loosely translated), used in the special sense of “place,” which includes localized climate, soil type, drainage, wind direction, humidity, and all the other attributes which combine to make one location different from another.

Thief: A type of pipette, used for sampling wine from the top of a tank.

Thin: Term used in sensory evaluation referring to a wine that lacks body, viscosity, alcohol, or sugar.

Topping: The act of filling a barrel or tank to the very top with liquid, usually wine of the same type and vintage.

Training: The act of guiding, pruning, and attaching a grapevine to a trellis.

Translocation: The process in which nutrients are moved through the grapevine.

Transpiration: Loss of moisture from a vine by evaporation through the leaves.

Trellis: The structure of posts and wires that supports a grapevine.

Titratable acidity: The measure of total acid in must or wine, which is expressed as its tataric acid content.

Trockenbeerenauslese: The highest category of sweet dessert wine produced in Germany. Meaning “dry berry selection,” it indicates that the raisined berries are individually picked to ensure that only fully raisin-dried grapes are used for the wine.

Troncais: Name of a category of French oak shipped from the Troncais region.

Trunk: The main, vertical body of a grapevine that supports all the top growth.

Ullage: The empty space above the liquid in a wine bottle, barrel, or tank. Too much ullage can lead to unwanted aerobic bacteria growing on the surface of the wine. Corrected by topping.

Varietal: A wine produced primarily from a single grape variety and so labeled.

Veraison: The mid-way point in berry development, when they change from green to purple (in red grapes) or green to lighter green (in white grapes) and become soft.

Vermouth: A fortified wine, red or white, which has been flavored by the addition of various herbs and barks (originally wormwood). Vermouth is used primarily as an aperitif.

Vidal: A French/American hybrid grape. Also known as Vidal Blanc.

Vigneron: Common French word for winegrower or winemaker.

Vignoble: Common French word for winegrowing.

Vignoles: A French/American hybrid grape.

Vintage: Term referring to the crop of a given year.

Viniculture: The science of growing grapes.

Vinifera: See Vitis vinifera.

Viognier: A vinifera species of grape.

Vitis vinifera (vee-tis vihn-ihf-uh-ruh): The infamous Eurasian species of grapevines that includes such varieties as Cabernet Sauvignon, Cabernet Franc, Chardonnay, Merlot, Riesling, just to name a few.

Yeast: Yeast is a fungus that feeds upon the sugar in the grape juice, converting it into alcohol, carbon dioxide, and flavor compounds.

Zymurgy: The science of fermentation.