Acetaldehyde A compound produced by fermentation and oxidation exhibiting fruity, chocolate, pumpkin type aromas. Acetaldehyde has been shown to assist in the stabilization of wine color. Acetic The vinegar-like off odor of acetic acid. Acetic acid can be formed by the action of the bacteria acetobacter. These wines often have a sweet, slightly vinegary odor and a sharp, tart flavor. Acetobacter The principal bacteria responsible for converting alcohol into acetic acid (vinegar). Acidity Tartness, the taste of natural fruit acids (tartaric, citric, malic or lactic) in wine. Minute traces of other acids are all found in wine. There are two measures of acidity used in winemaking; see pH and Titratable acidity. American Oak Oak of the genus/species Quercus alba harvested in the United States Anthocyanins The pigment compounds responsible for the color of red grapes Aftertaste/Finish The odors and flavors that linger in the mouth after swallowing or spitting out the wine. Usually the hallmark of a complex wine. Aging Holding wines for a period of time in barrels, tanks or bottles. Aggressive A term used to describe a wine with harsh flavors, often the result of too much tannin or acid. Aroma Odors in the wine that originate from the fermented grapes. Aroma should not be confused with bouquet, which is created during aging. Astringency A sensation of constriction within the mouth primarily caused by tannins absorbed from grape skins and seeds. Austere High-acid and typically young wines. Autolysis The self-digestion of yeast by enzymes contained in it. AVA (American Viticultural Area) A system implemented in 1983 created to identify the origin of US wines along the same lines as the French Appellation d'Origine Controlee system. An AVA is a geographic area only and has no impact on the variety of grapes grown or the wine making methods utilized. Backbone Wines with good acidity and tannin structure. Baked The caramel odor in sweet wines, such as Madeira, that have been heated at high temperatures. These wines often have a warm, earthy aroma. Also wines from over-ripe grapes Balanced A wine in which acidity, sweetness, tannin and flavor are all in perfect harmony. Balance The pleasurable proportional correctness of a wine's many aromatic and taste components, but especially sugar, alcohol, acidity, and tannin. Balling A scale for denoting the density of liquid in terms of specific gravity. Balling and Brix are identical scales used to estimate sugar content of the must. Barnyard A smell in wine similar to that of a barnyard, this can be caused by unsanitary winemaking conditions or by a yeast cell called Brettanomyces Barrel Fermentation The process of fermenting grape juice/wine in small barrels instead of large vats. Barrels are usually made from oak and are approximately 60 gallons in size, although larger and smaller sizes are available. Fermentation in oak imparts a variety of attractive aromas and flavors and often results in a richer creamier style wine. Barrique A Bordelais term for a 225 litre barrel (almost 60 gallons) Battonage Stirring of lees into the wine Baumé A term to measure Specific Gravity, which indicates the sugar content of unfermented grape juice. One degree baumé is equivalent to 1.8 degrees Brix. 1 degree baumé ferments out to approximately 1% alcohol. Bentonite A powdery clay found in Wyoming and Germany that is used as a fining agent to clarify wine. Body The consistency or density of a wine in the mouth. Botrytis cinerea/Noble rot A fungus that causes results in shriveled, concentrated grapes. It has been adapted as a desireable condition for wines such as French Sauternes, German Trockenbeerenauslese, and Hungarian Tokaji. Bottle shock A temporary period immediately following bottling during which the wine is flat, and less palatable. Bouquet The complex scent released when a bottle is uncorked. The bouquet may rapidly dissipate revealing the inherent wine fragrance (aroma). Brettanomyces/Brett A yeast that imparts strong aromas such as horsey, barnyard, bandaid, medicinal, leather and/or spice into wine Brix A scale for denoting the density of liquid in terms of specific gravity. Brix and Balling are identical scales used to estimate sugar content of the must. Bung A stopper used to seal a cask, keg or barrel. Canopy The shoots, and leaves of the grapevine during the growing season Cap The layer of skins and pulp that forms on top of the juice during primary fermentation. Carbon dioxide/CO2 The gas emitted by yeast during fermentation. Carbonic Maceration The fermentation of uncrushed whole grapes which takes place in the site cells of the berries. Carboy A large glass or plastic bottle. Chaptalize To add sugar to a must or wine. Chewy Full-bodied, rich, tannic wines Citric acid A colorless acid found in all citrus fruit, pineapples, and in lesser amounts in several other fruit. Clarity The clearness of the wine Clean A wine with no off smells or flavors. Clone A group of genetically identical, asexually propagated plants that can be traced back to a single plant. Cold soak Exposing the must to a brief period (1-3 days) of cold temperatures prior to fermentation to extract water soluble compounds Complexity A balanced, rich, nuanced wine demonstrating finesse. Corked A moldy odor and flavor from fungus-infected cork attributed to small amounts of trichloroanisole (TCA) in the wine. Crusher; crusher-stemmer A machine that breaks open grapes, it usually de-stems them as well. Decant To gently pour clear wine from the bottle into a serving container (decanter or carafe) leaving the bottle sediments behind Depth Describes a wine of persistently complex and intense flavors Diammonium phosphate/DAP A compound that may be added to the must in order to supplement available nitrogen required to ensure yeast health. When used correctly it can help minimize stuck and/or sulfidic fermentations. Dissolved oxygen/DO A measure of the soluble oxygen contained within a liquid Dry A wine low in residual sugar. Earthy A wine having mushroom and/or soil characters; alternatively it can be a descriptor for characteristics Brettanomyces imparts to wines. Elegant Typically well made, balanced, lighter bodied wines End grain The exposed end surface of the wood when cut across the grain Enology/Oenology The science of wines and winemaking. Enzyme Protein(s) that function as catalysts in biochemical reactions. Esters Volatile aroma compounds formed from the reaction of alcohols and acids. Ethanol/Ethyl alcohol The principal alcohol produced by yeast during fermentation of grape must. Ethyl acetate A compound with the odor of nail polish remover arising from a wine with high volatile acidity Extracted A very concentrated wine Extraction The process of drawing out compounds into wine. Fat A full-bodied, thick wine. Fermentation The process of yeast converting sugar into alcohol and carbon dioxide. Filtering The physical removal sediments from wine or juice Fining A winemaking technique involving the addition of a material such as egg whites, bentonite, milk, casein, gelatine, etc. for clarifying wines. Flabby/Flat Wines low in acidity Fleshy A wine with a soft, smooth texture. Flinty A stone or mineral-like character. Floral Tasting and/or smelling of flowers Free-run Wine or juice that is obtained without pressing Free SO2/FSO2 The unbound portion of SO2 forms available for antimicrobial activity French oak Oak of the genus/species Quercus robur, or Quercus petraea harvested in France Fruit bomb Soft wines from very ripe grapes that contain big fruit flavors and low acid levels Hard Aggressive wines high in acidity or tannins. Hogshead Usually a 60-gallon oak barrel Hot Unbalanced high alcohol wines. Hungarian oak/"European" oak Oak of the genus/species Quercus robur, or Quercus petraea harvested in Hungary Hydrometer An instrument for measuring the specific gravity of a liquid. This measurement is roughly related to the relative amount of sugar in your must or fermenting juice. Inoculate To add an active culture of yeast or malolactic bacteria to a must, juice or unfinished wine. Lactic Acid An organic acid produced in wine from malic acid during malolactic fermentation. Lean A wine is lacking in density and structure Lees A heavy sediment primarily consisting of dead yeast cells and grape pulp. Limousin A type of French oak cask, from the forests of Limoges, France Maceration Mixing of the grape skins into the wine to extract color, tannin and aroma. Also used for the grinding of pommace. Macro-aeration Dosing large amounts of air into the must or wine. This process is common during fermentation. Macro-oxygenation Dosing large amounts of pure oxygen into the must during fermentation. Maderized A wine that has developed oxidized characters Malic Acid An organic acid found in grapes and wine that is converted into lactic acid during malolactic fermentation. Malolactic Fermentation/MLF A bacterial fermentation that converts malic acid to lactic acid and carbon dioxide. Matrix The sum of all components making up a wine Maturation The process of aging wine in bulk or bottles to achieve smooth the acidity and mellow harsh tannins, while creating more complexity. Mature Wine which has reached its optimum point during aging. It is neither too young nor too old. It will exhibit a pleasing combination of sensory properties, aroma, flavor, texture. Mercaptans Unpleasant sulfury rotten smells found in some defective wines. Meso-climate The unique climate of a small subsection of a wine region Micro-oxygenation/Micro-ox/MOX Dosing minute amounts of pure oxygen into the wine during aging Monomer A simple molecule that can be linked in a repeated fashion to form oligomers and/or polymers Must The solid and liquid of crushed grapes used for making wine. Nevers Forests surrounding the town of Nevers where French oak is harvested. Nose The smell of a wine, combining both its aroma and bouquet Nutrient Nitrogenous matter, vitamins, and minerals necessary for yeast health Oaky A wine that has extensive aromas and flavors derived from toasted oak. Oligomer A medium sized compound made up of a linked series of repeated simple monomers. When dealing with wine phenolics this term is used for compounds with an average of 2-5 subunits Organoleptic The aroma and taste properties of a material Oxidized Wine changed by contact with air, usually producing undesirable characteristics like browning. pH A measure of acidity; the lower the pH the higher the acid strength. Pommace The remainder pulp and skins after pressing Polymer A large compound made up of a linked series of repeated simple monomers. When dealing with wine phenolics this term is used for compounds greater than an average of 5 subunits long Potassium metabisulfite A dry solid that yields SO2 when dissolved in wine. It is commonly used as the primary wine preservative. Press The act of using pressure to force juice out of fruit pulp. Also the device used to carry out this operation. Primary fermentation The initial alcohol fermentation of must by yeast. Procyanidins Skin and seed tannins derived from catechin or epicatechin monomers Procyanidins Skin tannins derived from gallocatechin or epigallocatechin Pumpover The process of dousing the cap at the top of a tank with wine from the bottom of the tank Rack and return/Delastage Removing all of the wine from one fermenting tank to another tank leaving the cap behind. After a set period of time the wine is pumped back over the top of the cap. Racking Siphoning or pumping wine from one container to another to clarify it by leaving the sediment behind. Reduced/Reductive Generally refers to negative sulfur containing aromas such as sulfides or mercaptans Residual sugar The amount of sugar left in a wine at bottling. Rehydration A vital step in the preparation of yeast where 104 0F water is added back to freeze dried yeast cultures. Robust A full-bodied and intense wine. Round A smooth balanced wine. Saignee Bleeding off a portion of juice after only a short period of skin contact to increase the skin to juice ratio of the remaining must thus concentrating the wine. Seasoning The process of aging wood in the natural elements to soften tannins, reduce astringency, and increase complexity Secondary Fermentation Synonymous with malolactic fermentation in still winemaking. In sparkling winemaking it is the process of fermenting in bottle to produce the carbon dioxide bubbles. Settling The natural precipitation of solids in wine. SO2/Sulfur dioxide A compound used to prevent wine spoilage (see potassium metabisulfite) Soft Smooth, easy drinking, low acid wines Sparge To introduce gas into a liquid Specific gravity The ratio of the density of a substance to the density of water Stave A narrow strip of wood Still wine Any wine that is not sparkling. Stuck fermentation A fermentation that has started but then stops before desired levels of sugar were converted into alcohol. Structure A combination of the texture, mouthfeel and balance that a wine imparts. Sulfides Sulfur containing compounds that can impart negative rotten aromas to wine Sulfites Sulfites are sulfur containing compounds that are natural by-product of fermentation. Sulfites are also used as a wine preservative (see potassium metabisulfite) Supple Big velvety textured wines Sur lie A French term for a wine left on the lees Tannin Natural phenolic compounds that precipitate proteins. In wine these compounds impart astringency and structure to the wine. Tartrates Crystals of tartaric acid that have precipitated out of the wine solution TCA 2,4,6-trichloroanisole, a compound responsible for the musty odor of "corked" wines Thief A tubular glass, plastic or wooden instrument for drawing a sample of wine from the cask or barrel. Thin A wine lacking body. Toasting The process of heat treating oak Toasty A flavor imparted by fire treated oak Total SO2/TSO2 The entire amount of SO2 in all of it forms contained within the wine Turbidity The decrease in transparency of a solution due to suspended solids Ullage The air space between the surface of the wine and the bottom of the bung, cork or other closure. Varietal character The aromas and taste sensations typical of a particular grape variety. Vegetal A description of wines that have green vegetables odors Velvety A soft, silky, lush mouthfeel Venturi A valve that draws air into a fast flowing liquid Vinous A wine without a specific, distinguishing odor. Vitis vinifera The species of grapevines most responsible for producing the world's best wines, including Pinot Noir, Chardonnay, Cabernets, etc. Volatile acidity/VA A measure of the low boiling point acids in wine. High levels of volatile acids, notably acetic acid, are an indicator for wine spoilage Whole cluster press The process of pressing intact clusters of grapes without destemming or crushing the fruit first Wine The fermented juice of grapes Yeast Unicellular fungi capable of fermenting sugars. Yeasts of the genus Saccharomyces are commonly used for winemaking.