Grape & Wine
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Terminology

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Acetobacter: A group of bacteria that oxidatively convert wine to vinegar (Ethanol into acetic acid) through an aerobic (oxygen present) fermentation.

Acidification: The addition of acid during fermentation, frequently necessary in hot climates where grapes tend to overripen and become deficient in acidity, thereby losing freshness. Often used with other fruit based wines.

Acidity: The acids in a wine provide liveliness, longevity and balance: too much leaves a sour or sharp taste on the palate, while too little results in a flabby, shapeless wine.

Aeration: The process of incorporating air into a wine, must, or juice. Usually through splashing while racking, sparging with air, or simply by stirring a container very vigorously. This is sometimes done to "blow off" undesirable aromas such as hydrogen sulfide, or to give an initial dose of oxygen to a fermentation just getting under way.

Aerobic fermentation: Fermentation in the presence of air (Oxygen) usually called the primary fermentation.

Alcohol: see Ethanol.

Amelioration: Adding water, sugar, and chemicals to the must in order to make a better wine.

American Hybrid: A Hybrid cultivar which was created, in America, in a direct effort to improve wine quality by minimizing the tendency of the American cultivars to produce grapes which yielded a distinctive "foxiness" to the resulting wine. These cultivars are the result of the intentional genetic combination of two or more other cultivars, in an effort to squelch the foxiness of any American parentage.

Ampelography: The science of identifying grape varieties by detailed description of the appearance of the vine, especially its leaves (shape & texture), clusters (size & configuration), & berries (color & size).

Anaerobic fermentation: Secondary fermentation, or fermentation without the presence of air (Oxygen).

Anthocyanin: The natural phenolic glycoside compounds found in the skins of red wine grapes which most strongly influence a red wine's color. These are the compounds, which produced "reds" & "blues" of fruits and flowers.

Antioxidant: Compound that retards oxidation and slows its effects in wine (browning, sherry-like aromas). Sulfur dioxide, SO2, is the most widely used winemaking antioxidant. It also serves as an antimicrobial agent.

Astrigency: The dry, puckery sensation caused by tannin in wine. The tannins actually denature the salivary proteins, causing a rough "sandpapery" feel in the mouth.

Autolysis: Process where yeast start to feed off of dead yeast cells in the lees. This can lead to off flavors and odors. Prevent from happening with periodic rackings.

Avorton: French for 'runt'. When a vine is planted with two buds exposed, one of the two resulting shoots will almost always dominate over the other. The lesser of the two shoots is the avorton.

Balanced pruning: Pruning a vine based on its growth in terms of the amount of one year old wood it produced the previous growing season. A method of determining the fruiting capacity of a vine this season by weighing the wood removed at pruning time after the past season.

Balling: A scale to show how much sugar is present in must. Interchangeable with Brix.

Barrel: Most of the world's greatest (and some of the worst) wines are at least partially aged in barrels, usually made from oak. A barrique is the standard Bordeaux barrel, holding 225 liters or the equivalent of about 300 bottles of wine.

Base (Basal) shoot: A shoot arising from a but located at the base of a cane.

Bentonite: an inorganic fining or clarifying agent made from diatomaceous earth.

Black rot: a fungal disease of the vine.

BRIX: A scale used to indicate soluble solids content. It is basiclly the percentage of sugar in a solution. Brix = grams of sugar per 100 grams of liquid at 68F.

Botrytis (Bunch rot): A fugus which can either affect grapes benevolently (as in the 'Nobel Rot' responsible for great sweet wines) or, more commonly, simply spoiling them with mold, depending on conditions.

Bud: The compound eye in the axil of a leaf, located at a node. This is where the next year's growth and crop comes from.

Callus: Parenchyma tissue that grows over a wound or graft and protects it from drying or injury. This material also forms at the base & nodes of cuttings being prepared for planting. In this case, the callus represents the primordial roots of the cutting.

Calyptra: The petals of a grape flower.

Cane: a mature woddy, brown shoot as it develops after leaf fall. Canes were last years fruiting or renewal shoots. The buds on the canes will produce the next season's fruiting shoots.

Cap: Fruit skins, stems, and pulp that float to the surface during fermentation. It is essential to "punch down" the cap into the wine during a red wine fermentation to extract valuable tannins and color compounds as well as to discourage the proliferation of spoilage organisms in the cap.

Chapitalization: The addition of sugar during fermentation to increase a wine's alcoholic strength. More commonly used with non-grape wines.

Chateau Bottled/Estate Bottled: Bottled at the house or place where the wine was made/grown.

Chillproofing: Deliberately exposing wines to very cold temperatures prior to bottling to, primarily, precipitate any tartrate crystals that might com out of solution later. It is seen as more of a quality control step than a necessity for home winemakers.

Clone: an example of a variety replicated using a cutting from a specific mother vine, which is selected as a result of some particular attribute(s). Hence, the new vine will be genetically identical to the parent. Due to the targeted nature of the clonal reproduction, the offspring vines will carry a specific designation identifying them as clones. Within certain cultivars (such as Pinot Noir) clonal variation tends to be very important.

Coulure: Deficient fruit set which may substantially reduce the size of the current year's crop. Just after flowering, an excessive proportion of the nascent berries fall off, often because of unsettled cold, wet weather or inadequate thinning of unfertilized berry clusters.

Cross: A cultivar, which is the result of a crossing of two or more cultivars within the same species (may be intentional or unintentional).

Crown Gall: A bacteria disease of the vine (usually facilitated by freeze injury to the vine's tissue).

Cultivar: The type of vine from which a variety of grape grows.

Cuvée: A blend of old and new wines typically for champagne production. In general it is the resulting blend of different wines (either by year, source, or type) to produce a consistent quality of wine year after year.

Decanting: Process of separating a wine from any sediment that may have formed. This is essential for Vintage Port and for older reds (which naturally throw a deposit). Aeration is a by-product of decanting, though wine is most efficiently aerated ('allowed to breathe') by swirling in the glass.

Diammonium phosphate: A source of nitrogen for stuck fermentation's.

Dormancy: That stage when the plant is not actively growing. For grapevines it is usually characterized by average air temperatures below 50F. Vines need a minimum of about 60 days of dormancy.

Downy Mildew: A fungal disease of the vine.

Enology (Oenology): The science of winemaking.[ Coined from Greek oinos "wine" + -logy.]

Ethanol/Ethyl Alcohol: a colorless liquid with a pleasant smell that is produced naturally from fermentation by yeasts and other microorganisms. It is used in alcoholic beverages, as a solvent, and in the manufacture of other chemicals. Its chemical equation is C₂H₅OH. It is the only one of the hydroxyl group of compounds that can be safely consumed in any quantity. Other Alcohol's in the hydroxyl group that are in common use include Methyl (wood), Isopropyl (rubbing), Butyl (perfume base), Polyhydric & Trihydric(glycerol).

Eutypa Dieback: A fungal disease of the vine. Also known as 'Dead arm'.

Fanleaf: A viral disease of the vine.

Fermentation: The conversion of fruit juice into wine through the action of yeast's present in the juice, which turn sugar into alcohol and CO₂. This alcoholic fermentation is also known as primary fermentation.

Field grafting: Grafting a new variety on to an established rootstock already growing in the vineyard.

Filtration: A method of clarifying and stabilizing wine to give it a pleasingly lucid color and to remove yeast's, bacteria or other solid matter that might otherwise spoil the wine after it has been bottled. Excessive filtration, like excessive fining, can strip a wine of aroma, body, texture and length.

Fining: A method of clarifying wine by pouring a coagulant on top and letting it settle to the bottom. In general, a fining agent is allowed to fall through the wine, while filtration, the wine is passed through a filter. Some common fining agents are egg whites, Bentonite, Sparkalloid, and Gelatin.

Foxy: The distinctive taste of the grapes and wine of some Native American cultivars, especially Vitis labrusca and some of its hybrids. Methyl anthranilate is (often) the offending compound.

Fruit (berry) set: In France it's called Nouaison. An early summer phenomenon which immediately follows flowering. As soon as the vine flowers, a proportion of them are fertilized, or 'set', to become berries, and eventually grapes. The higher the proportion, the bigger the crop is likely to be.

Fruiting Zone: A horizontal band running down the row of vines, wherein all of the fruit clusters can be found. Many grape growers will often aim to create a tight or narrow fruiting zone so that certain vineyard operations (such as leaf removal around the clusters & harvesting) can be simplified.

Fungicide: A chemical or physical agent that kills fungi or inhibits its growth.

Gall: An abnormal growth of plant tissue caused by stimuli external to the plant itself. Generally caused by insects (as in Phylloxera leaf galls), bacteria (as in Crown Gall) or parasitic fungi.

Grafting: Broadly, inserting a section of one plant into another so that they unite and grow as one plant. In a viticultural context, usually grafting a European fruiting vine (or scion) onto a native or hybrid rootstock, often chosen for its resistance or other favorable characteristics.

Heat Summation Units (HSU): The "heat summation units" for any given growing site is calculated by totaling the number of day degrees above 50F (10C) for the entire growing season.

Hybrid: A cultivar bred from members of different species. A cultivar which was created by the intentional genetic combination of two or more other cultivars (either intra or inter-specific), in an effort to promote the most desirable characteristics of each parent cultivar.

Inflorescence (French): The flower cluster of the grapevine. It consists of many tiny individual blossoms, each attached by a tiny individual stem to a larger stalk to form a compound flower.

Insect Pests: The major insect pests of the grapevine are: the grape berry moth, the Japanese beetle, the grape flea beetle, the European red mite, the grape phylloxera, the grape borer & the blue-green or Glassy winged sharpshooter (as a vectors for Pierce's disease).

Internode: The portion of the cane or shoot between nodes.

Lateral: Side branches of a shoot or cane.

Leaf: The primary source of green on the grapevine. Along with dentrils & clusters, the leaf is grown on the shoot and it is the vine's primary engine of photosynthesis. Although the grapes get some of their sugar from the carbohydrates stored in the perennial wood of the vine during the earliest stages of ripening, the vast majority of sugar production is performed by the vine's leaves during the middle and later stages of ripening. Also used in viticulture to refer to the age of a vine; as in: a vine in its "third leaf" is three years old.

Leafroll: A virus disease of the vine.

Lees: Solid residue (mostly dead yeast cells and fruit pulp, pips and skins) that remains in the cask after the wine has been drawn off. Many white wines and some reds are kept on their lees for a period of time to protect them from oxidation, enrich their textures and add complexity. Wines protected by lees contact can often be made with less sulfur addition, but careful technique is essential to ensure that off aromas don't develop. This process is known by the French term 'sur lees'.

Lesion: A wound or delimited disease area.

Maceration: The processes through which red wine grape (or other fruit) skins, seeds, and pulp are mixed and mashed in with the fermenting juice to extract tannins, colored compounds, and aroma from the fruit. Different maceration programs have different effects. For example if you stir red wine while it ferments (often called "punching down") twice a day as opposed to once a week, you should extract more color and tannin from the skins and seeds of the fruit into the finished wine than if your strategy was less aggressive.

Malolactic Fermentation: A secondary fermentation in which the more tart malic acid is converted into softer lactic acid and carbon dioxide. Malolactic fermentation, which generally follows the alcoholic fermentation, is nearly always carried out in red wines. Some producers of white wines encourage MF, while others especially those in hot regions that produce grapes with low levels of acidity, avoid it in order to retain the wine's freshness.

Millerandage: Abnormal & uneven fruit set in which bunches contain berries of very different sizes because of poor fertilization, often caused by unfavorable weather or improper thinning of unfertilized clusters.

Muscadine: A Native American species of grape indigenous to south Atlantic region of the US. With the scientific classification Vitis roundifolia, the muscadine grapes have a very unique, intense, fruity aroma and are so genetically different from the other vitis species that they can only be crossed with the former through the use of very modern, sophisticated genetic technology. Botanists have given this unique group their own sup-genus (Muscadinia), unique from the "true" grapes (sub-genus Euvitis). Common varieties of Muscadines used for wine making include: Red: Burgaw, Eden, Hunt, James, Mish & Thomas. White: Scuppernong, Topsail, & Willard.

Must: A red wine making term that refers to the soupy mass of squished skins, seeds, and pulp that are fermented together. "Must" can also be applied to fruit winemaking, it refers to the gloppy pulp/skin mixture to which the yeast are added. Essentially the winemaker's raw material. In contrast if the pulp and other solids are pressed off before fermentation, the raw material is simply "juice".

Mycorrhizal fungi: A type of fungus, which is often applied to the roots of a vine at planting. The mycorrhizae forms a mutually beneficial relationship with the plants roots. As such it acts as an extension of the root system, increasing the roots' ability to absorb nutrients and water. Some research indicates that the co-dependent symbiotic relationship between the fungi and the vine helps the vine to survive stress, absorb more water and nutrients, and increase its resistance to soilborne diseases.

Native American variety: Of the families Vitis Labrusca, Vitis Riparia, Vitis Rupestris and others. A cultivar belonging to the many and divers vitis species indigenous to the North American continent. Some common varieties used in winemaking include: White: Niagara, Pink: Delaware, Red: Concord, Catawba, Norton (or Cynthiana), Steuben.

Noble Rot: The benevolent form of botrytis. Usually caused by an early morning, high humidity, fog or dew, allowing for primary infection, which is followed by a windy, warm morning.

Node: The thickened portion of a shoot or cane where the leaf and its compound bud are attached.

Oenophile: somebody who has a passionate interest in wine or is an expert on wines (formal). [from French, from oeno- , from Greek oinos "wine."]

Oenotherapy: The medicinal use of wine.

Oxidation: Chemical term relating to the reaction of juice, must or wine with oxygen. Typical negative side effects of such reactions are browning of wine and juice and "cooked" flavors and aromas. Limited amounts of oxidation are actually healthy for wine, because yeast need oxygen to grow during the initial stages of fermentation. Protracted, slow oxidation is a key physiological change that takes place when a wine ages.

Pectins: Complex carbohydrate chains naturally occurring in fruits that contribute to the viscosity and haziness of a wine. The can be shortened and solubilized (dissolved) by pectic enzymes, which are sometimes used in winemaking when dealing with non-grape fruit.

Perennial Wood: The permanent wood of a grapevine. It is the older, "woodier", thicker wood of the trunk & cordons of the vine.

Pétillant: Fizzy, or slightly effervescent wine. [From French, "effervescent," literally "passing gas."]

pH: An acidity scale that will tell you how acidic or basic your wine is. Most wines will be in the neighborhood of 3.5 pH. The pH has an effect on several activities such as sulfiting, age-ability of the wine, fining, etc.

Phenolics: A varied group of compounds found mainly in skins, stems, and seeds in the case of grapes. They include anthocyanin, tannins and many flavor compounds. Precipitated, they form an important part of wine's sediment and play a considerable role in wine aging. Phenolics are known to have beneficial effects on human health. Red wines are much higher in phenolics that white, which is why red wine is better at protecting against, heart disease.

Phylloxera: Fatal vine pest that destroys the soft vine roots of vitis vinifera cultivars. The only remedy is to replant on phylloxera-resistant rootstocks. The roots of most Native American & hybrid vines are immune to the effects of the pest. Phylloxera will generally not inhabit soils that are 80+% sand. In all other soil textures, vinifera cultivars should be grafted onto phylloxera resistant rootstocks.

Pierce's disease (Xylella Fastidiousa): A bacterial infection of the vine that is spread by insects such as the blue-green or glassy-winged sharpshooters. What is now called Pierce's disease was known as Anaheim's disease in the 1880's when it wiped out thousands of acres of vineyards in southern California. In very warm climates, such as Florida, PD has rendered commercial vineyard development all but impossible. The name Pierce refers to Newton B. Pierce, California's first professionally trained plant pathologist, who was the first to attempt to isolate the cause of the disease. The disease affects the Xylem of the plant in such a way that the plant is no longer able to transport sap due to the blockage in the Xylem. Most Native American cultivars, and some Hybrids appear to be unaffected by this bacteria, but can become vectors for the bacteria. There is currently no cure once a plant is infected, and it should be removed.

Powdery Mildew: A fungal disease of the vine. This was the major grape pest in California, until PD became rampant.

Primordial Shoots: The buds, which develop on this year's fruiting wood. They will give rise to the fruiting shoots for the next vintage.

Pruning: Aside from weed control, the single most important operation of the vineyard year in terms of wine quality. Simply put, pruning is the removal of portions of the vine for the purpose of maintaining its size & productivity. The size and productivity is maintained by ensuring that the vine retains a proper number of fruiting buds. During either fall or winter, the wood of the vine is cut back leaving a specific number of buds (usually from 20-40) on one year old wood (canes or spurs) which will produce the crop for the next vintage. Although many other factors come into play, low-yielding vines in general tend to produce more concentrated wine.

Punt: The indention in the bottom of still wine and sparkelling wine bottles. Originally it was an indicator of a quallity made bottle. It also provides strength to sparkelling wine bottles.

Racking: Transferring the wine from one cask (or carboy) to another to separate it from its lees.

Rootstock: A cutting taken from a vine (usually Native American or hybrid) and cultivated to serve as a rootsystem for a grafted vine. Hence a grafted vine consists of a scion (above ground growth) and a rootstock (below the ground growth).

Ropiness: A condition in which wine resembles slime, raw egg whites, or mucous. It is caused by an extreme microbiological contamination that produces long-chain carbohydrates (polysaccharides), hence the "ropiness".

Scion: A cutting (or bud wood) taken from a vine (usually vitis Vinifera) and grafted onto a rootsystem from another vine. Hence a grafted vine consists of a scion (above ground growth) and a rootstock (below the ground growth).

Sediment: Solid matter deposited in a bottle during the course of the maturation process. Sediment is generally a sign that the wine was not excessively filtered prior to bottling.

Shatter: The physiological stage following bloom when impotent flowers and green berries begin to fall from the cluster. Also used to refer to the annoying habit of some cultivars to have their over-ripe grapes simply fall from the vine.

Shoot: The green, leafy growth developing from a but on a cane, spur, cordon, or trunk. The developing growth of the shoot is the source of al of the vine's leaves, stems, tendrils, flowers & fruit.

Spur: A cane pruned to 3 or fewer nodes, generally on a cordon. A "Renewal Spur" is a spur whose primary purpose is to position a cane for fruiting the following season.

Sucker: A shoot arising from a bud below ground. Can be used to create multiple trunks. (Note: MUST be removed from a grafted vine as the sucker is originating from the rootstock, not the scion)

Sulfur: The most common disinfectant for wine. Most winemakers feel that it is nearly impossible to produce stable wine without judicious use of sulfur products at one or more stages of vinification: just after the harvest to thwart fermentation by the wrong yeast's, in the cellar to prevent microbial spoilage and oxidation and at the time of bottling to protect the wine against exposure to air. But as a general rule, the amount of sulfur used in the production of fine wine has never been lower than it is today. The 2 formulations that wine makers have available for use is Potassium Metabisulfide (prefered), and Sodium Metabisulfide. It is typically measured in parts-per-million (ppm). Common form is Campden tablets.

TCA: 2,4,6-Tricloroanisole, a chemical compound that is one of the major sources of the "cork taint" off-odor.

Tannin: A bitter, mouth-drying substance found in the skins, stalks and pips of the grapes -- as well as in wood (Oak) barrels. Tannin acts as a preservative and is thus important component if the wine is to be aged over a long period. Tannins are frequently harsh in a young wine, but gradually soften or dissipate as the wine ages in the bottle.

Titratable acidity: Also known as "total acidity", titratable acidity is the total amount of all hydrogen ions (what makes acids "acidic") in a solution of juice, must, or wine. It is the measure of all aggregate acids and a sum of all volatile and fixed acids.

Tendril: A curled structure arising from some nodes of the shoot and capable of attaching itself to other portions of the vine & non-vine structures (like trees or a trellis). They give the vine the ability to climb.

Terroir: French for soil. The ecology of a wine. The total, inter-related environment wherein a grapevine is cultivated for the purpose of making wines. Key factors include, but are not limited to, cultivar type, soil, climate, vineyard location, planting density, training system, pruning philosophy & the cultural and social milieu wherein the whole enterprise takes place.

Trellis: A lattice for supporting a plant typically made of wood, metal, or plastic. Vineyard trellis systems are typically constructed with heavy end posts with wire strung the length of the row, and light 'T' posts or grape stakes are place periodically to provide support during the growing season.

Vérasion: (French) The physiological stage in the development of a grape berry when it begins to ripen as indicated by a softening of the fruit & and a change in color (red for dark varieties & translucent for white varieties.)

Vigneron: (French) Grower of grapes for wine: somebody who grows grapes for use in making wine

Vigor: A vine's natural tendency to sprout forth leaves & other green growth (often at the expense of quality fruit production).

Vine Density: Important vineyard parameter, the number of vines planted per unit of area (usually acre). New World plantings tend to be relatively low density (less than 800 vines per acre), while Old World plantings tend to be very hive density (1000+ vines per acre). Density is directly determined by vine spacing (the distance between the rows of vines & the distance between the vines in the rows).

Vinedresser: grapevine pruner: somebody who tends and prunes grapevines.

Vinegar: a sour-tasting liquid used to flavor and preserve foods. It is a dilute acetic acid made by fermenting beer, wine, or cider. From Old French vyn egre "sour wine," from Latin vinum acre.

Vineyard: 1. Place where grapes are grown: a piece of land where grapevines are grown.
2. Sphere of endeavor: any sphere of mental, physical, or spiritual endeavor.

Vinifera (Vitis Vinifera): Vine species of European origin. Members of this species are known for their ability to produce the finest grapes for wine. The most "Nobel" examples are Cabernet Sauvignon, Pinot Noir, Chardonnay, & Riesling.

Vinification: The process where liquid is fermented into wine.

Vintage: Can mean either the particular year in which the crop was harvested or the actual process of the annual crop's growth & harvesting.

Viticulture: The science of grape growing.

Vitis: The vine genus, of which grapevines are a member.

Volital Acidity: Acid created during fermentation by spoilage organisms that are introduced by contact with fruitflies or other air-borne insects or contaminants. Refers usually to acetic acid (vinegar) produced by contamination by acetobacter bacteria. Keep fermenting wine covered to avoid problems.

Water Sprout: A shoot arising from a but located on the wood, which is older than one year old (usually the trunk). Generally it will not be fruitful & is unwanted.

Weed: Any unwanted plant.

Wine: An alcoholic drink made by fermenting the juice of grapes or other fruits. [Old English wn , from Latin vinum (source of English vine and vinegar). Ultimately from a pre-Indo-European word that is also the ancestor of Greek oinos (source of oenophile).]

Yeast: The various microorganisms that cause fermentation. Wild yeast is naturally present on grape skins, but cultivated yeast is generally used to control fermentation more carefully. Current strains allow winemakers to control different factors from flavor to dryness of the wine.

Yield: The amount of wine or grapes produced per unit area, usually measured either as ton/acre, tons/ha or in much of Europe, hl/ha. Many factors such as planting density, pressing regime, grape variety, and style of wine affect the conversion of weight of grapes into volume of wine.

Document last edited May 20, 2002