See Alcohol by Volume.

A colorless, volatile, and water-soluble compound found naturally in grapes and wines in trace amounts and produced both by fermentation and oxidation. It has a pungent, fruitlike odor and is desirable in small amounts in good table wines and in high amounts in oxidized wines such as Sherry or Madeira. During fermentation, it is produced by yeast in the fourth of five stages of enzymatic action culminating in the production of ethyl alcohol. The enzyme carboxylase forms acetaldehyde and carbon dioxide from pyruvic acid. At the next (final) stage, most of the acetaldehyde is reduced to ethyl alcohol, but a trace remains and adds to the flavor and complexity of the wine. If too much remains, it taints the wine with a strong, oxidized off-taste.

In wine evaluation, the odor of acetic acid and ethyl acetate.

The organic acid that imparts the sour taste to vinegar, formed by the action of the bacteria acetobacter.

The formation of vinegar, usually caused contamination of the must, liquor or finished product with vinegar-producing bacteria (acetobacter) and the presence of air. Fermentation bottles should be filled as high as the froth or foam caused by fermentation will allow and the topped up as foam production subsides. Stored wine should have no more than one inch of air under the cork in the standing bottle (2/8 to 1/2 inch is preferred). Adding one Campden tablet per gallon may halt acidification in its early stages, when the wine emits a slight smell of vinegar and an acid taste. When the smell of vinegar is strong, however, it is probably too late to save the wine, but you might want to go ahead and make some wine vinegar instead. NEVER make wine in a wooden cask or barrel or plastic primary that has contained vinegar, even if acidification was successfully halted.

The principal bacteria responsible for converting alcohol into acetic acid -- vinegar.

A blend of acids important to wines, usually tartaric, malic and citric acids. While there are many different formulations of acid blend, the recipes on this site calling for acid blend assume a blend of 50% tartaric, 30% malic and 20% citric. If your acid blend uses a different ratio, you may want to use slightly more or less depending on your blend.

The amount of acid in the must, liquor, or finished wine. Insufficient acidity in the must will result in a poor fermentation and a slightly medicinal and flat taste. Too much acid will give the wine an unpleasant sourness or tartness. Some acid is necessary for fermentation, and up to one-fourth of the initial acid content will be consumed by the yeast during fermentation. Low-acid musts are usually corrected by adding tartaric acid (the principle acid in grapes), malic acid, citric acid, or acid blend. An acid testing kit is indispensable in measuring initial acidity. There are two measures of acidity used in winemaking; see pH and Titratable acidity.

The process of adding natural grape acids, primarily tartaric and/or malic acid, to a wine to increase its titratable acidity.

A term denoting excessive total acidity. The threshold for acidulousness is undefined, but certainly a wine with a pH less than 3.1 or a titratable acidity more than 0.9% will taste sour and acidulous. The opposite (taste denoting insufficient total acidity) is flat.

A hydrated, feeding, reproducing colony of yeast. The colony may have formerly been stored as active dry yeast (ADY), as a dense liquid colony under refrigeration, as dried yeast on grape skins and pulp, or in several other forms. See Yeast Starter.

A dehydrated yeast culture that is the most convenient form of yeast for home winemakers to work with. Active dry yeast (ADY) cultures are prepared by extruding 70% moisture compressed yeast through a perforated plate into a spaghetti-like form, about the diameter of a 0.036 inch pencil lead, into a drier with a screen bottom that has a upward flow of air that keeps the particles of yeast suspended in a fluid-like bed. The incoming air is controlled for volume, temperature and relative humidity. The drying from the original 70% moisture down to 4-7% occurs in less than 30 minutes. There are typically over 150 billion cells in a 5-gram sachet of ADY. The ADY should be rehydrated in a starter solution (see Yeast Starter) before "pitching," both to ensure the culture is still good and to get a vigorous start.

See Active Dry Yeast.

A fermentation conducted in the presence of fresh air, as in a crock, vat, tank, or polyethylene pail. Aerobic conditions are necessary for yeast to rapidly reproduce to a density conducive to the fast production of alcohol.

The lingering taste, odors and mouth-feel that remain after a wine is swallowed. Also known as Finish, although this word has other meanings associated with wine. In wine judging and evaluation, where the wine is spit out to prevent intoxication and impairment of the judges or evaluators, aftertaste is not judged.

The process by which wine matures, in bulk or in bottles or both, to achieve smoothness (in acidity), mellowness (in tannins and other phenols) and unique character and complexity. The major activities in this process are the chemical reduction of certain compounds into others, primarily by hydrolysis or oxidation, and the joining together of short molecular chains into longer ones. Volatile esters, ethers and acids create bouquet, which is not the same as aroma.

A glass or plastic device designed to use water as an insulator to protect the fermentation media from contamination and exposure to fresh air, while at the same time allowing carbon dioxide produced by the yeast to escape the fermentation vessel. Also called a fermentation trap, bubbler or airlock.

Shorthand term for ethyl alcohol or ethanol, a product of yeast fermentation. The volumetric amount of alcohol in wine is usually between 9 and 14%. Beverages with less than 9% abv (alcohol by volume) are vulnerable to spoilage bacteria and require refrigeration for preservation. Beverages with more than 14% abv may technically be wine, but have other names such as Madeira, Sherry, Port, or are typed as Aperitif or Dessert Wines.

The amount of alcohol in a volume of wine, expressed as a percentile.

Technically, to add any substance to the must or new wine intended to enhance its quality, such as sugar, water, sweet reserve, or acid. However, there is another term specific to adding sugar (see Chaptalize), so ameliorate usually refers to adding water to a fruit or wild grape must.

An enzyme that hydrolyzes starch to produce dextrins, maltose, and glucose.

A fermentation conducted in the absence of fresh air, as in a fermentation bottle, jug or carboy fitted with a fermentation trap.

In grapes, the pigments that contribute the red and purple colors to their wines. In most other fruit, the bright reds, purples, blues, and indigos.

Additives such as ascorbic acid and sulfur dioxide which, when added in the right quantities, limit the oxidizing effect of oxygen contact with wine during various processes such as racking, filtering, and bottling.

A type of wine, usually 14% or more abv, to which a blend of herbs or spices have been added and which is served before a meal to stimulate the appetite. The best know aperitif is vermouth.

The natural fragrance of a wine that originates from the fermented fruit upon which the wine is based. Aroma should not be confused with bouquet, which is created during aging.

Often called "Vitamin C" by laymen, for a short time ascorbic acid was thought to be a viable substitute for sulfur dioxide (SO2) in wine; i.e. it was thought that ascorbic acid would protect wine against oxidation as well as SO2 does. Research has demonstrated this belief to be false. In an oxidative environment, ascorbic acid leads to rapid browning of catechin, a component of wine. The co-presence of SO2 delays the browning, but the delay is prolonged without ascorbic acid present. In other words, the wine ages better with sufficient SO2 present and without any ascorbic acid.

French term for "assembling," or blending of wines. In actuality, it is the art of judging the various wines available, which can be considerable, to determine which, when blended appropriately, can compliment or reinforce each others' strengths and overcome corresponding weaknesses.

Both a taste and tactile quality noted for constricting or contracting the inner mouth, as an unripe persimmon would, but caused in wine primarily by tannins absorbed from the skins and seeds of the base from which the wine was made. An excessively astringent wine is said to be "rough" or "harsh" or "tannic." Astringency is particularly noticeable in young, red table wines. Astringency tends to mellow or smooth out with aging. It differs from bitterness in that astringency is felt throughout the mouth, while bitterness is experienced only by the taste buds of the tongue.

The pleasurable, proportional correctness of a wine's many aromatic and taste components in harmony, but especially sugar, alcohol, acidity, sugar, and tannin. The taste or aroma of the base ingredient (fruit, flower, or other botanical component), or its absence, may also be said to contribute to balance, although this is a minor consideration and should more correctly be associated with the wine's character.

One of several hydrometer or saccharometer scales denoting the density of liquid (must, juice or new wine) in terms of specific gravity. Both the Balling and Brix scales are identical and are usually used to finely estimate sugar content.

A British specialty brown sugar, very dark brown, with a particularly strong molasses flavor. The crystals are slightly coarser and stickier in texture than "regular" brown sugar. Also know as Muscovado Sugar.

The significant fermentable ingredients from which wine is made and its flavor or aroma derived. Apple wine, for example, is made from a crushed apple base. The base is also known as the fermentation media.

A powerful sterilizing compound excellent for equipment, but should never be added to the must. One tablespoon to 1 gallon of water provides sufficient potency. Unlike potassium metabisulfite and sodium metabisulfite, B-Brite in solution may not be stored for future use, but must be made afresh each time it is needed.

A very fine clay used as a fining or clarifying agent in wine to remove protein, to achieve Heat Stabilization or to remove another fining agent.

A lingering taste sensation, detected totally in the mouth on the taste buds of the tongue, and therefore differs from astringency, which is tactile (felt) and experienced elsewhere in the mouth as well. Bitterness is most often associated with polyphenolic compounds, especially tannin, but high sulfate (not sulfite) content can also produce bitterness. Bitterness can be partially alleviated by fining, partially masked by sweetness and partially eliminated by aging. Some bitterness is expected in wines (especially red wines), but in excess is a fault.

The process of combining different wines to create a composite that's better than any of the wines separately. The wines blended might be from different varieties, different regions, different wood- and non-wood-aging, different vintages, and even wines made from different fruit.

A dusty coating on grapes and most other fruit, composed of dust, wild yeast, bacteria, and fungal spores. Often, but not always, a waxy substance on grape, plum, cherry, and apple skins containing the same substances.

A venting tube exiting a bung and either fitted with a valve or seated in a sulfite solution. When a demijohn or carboy is used as a primary fermentation vessel, the blow-off tube allows foam formed during the initial, violent period of fermentation to escape without disturbing the integrity of the airlock.

See Mead

The real or perceived consistency or density of a wine derived from several components of wine -- primarily alcohol and glycerin in combination, both of which are products of fermentation by yeast.. Real body refers to a wine that truly is thicker in density as a liquid, while perceived body is a wine's feel in the mouth whether truly denser or not. A full-bodied wine, such as Burgundy, is more easily sipped and may be referred to as "chewy," while a light-bodied wine such as Bordeaux is easily swallowed. A thin or "watery" wine lacks body altogether.

The most common wine bottle size worldwide is 750 ml, but it is not standard. Some German wine bottles are a liter, some are 700 ml, while some from Alsace are 720 ml. Every wine bottle consists of a mouth, neck, ogive or shoulder, body, and bottom. The bottom may contain an indention, the term for which is a punt. Some almost standard names for different size wine bottles are:

• Sample: 175 mL

• Split (Sparkling): 187 mL

• Picolo: 187 mL

• Chopine: 250 mL

• Half-Bottle, Demi, Split (still wine): 375 mL

• Pot: 500 mL (Beaujolais table bottle)

• Winston: 600 mL

• Clavelin: 620 mL (Jura bottle)

• Bottle, Standard: 750 mL

• Magnum: 1.5 litres

• Tregnum, Marie Jean: 2.25 litres

• Double-Magnum: 3 litres (Bordeaux shaped)

• Jeroboam (Sparkling): 3 litres (Burgundy shaped)

• Jeroboam (Still): 4.5 to 5 litres (Bordeaux shaped)

• Rehoboam: 4.5 litres

• Imperial (Still): 6 litres (Bordeaux shaped)

• Methusalah (Sparkling): 6 litres (Burgundy shaped)

• Salmanazar: 9 litres (Bordeaux shaped)

• Balthazar (Sparkling): 12 litres (Burgundy shaped)

• Nebuchadnezzar (Sparkling): 15 litres (Burgundy shaped)

• Melchior: 18 litres

• Solomon: 20 litres

• Sovereign: 25 liters

• Primat: 27 litres

• Melchizedek: 30 litres

The aging of wine in the bottles it will be distributed in rather than in vats, barrels, casks, demijohns, carboys, or gallon jugs. Bottle aging preserves the bouquet, which can be lost when the wine is bulk aged and then transferred to bottles. However, a bulk-aged wine can be bottled and subsequently develop a bottle bouquet.

A wine's bouquet, captured in the bottle the wine is aged and distributed in.

A period following bottling during which the wine is flat, uninspiring and possibly unpalatable. This is a temporary condition which usually lasts no longer than a month and rarely two.

The process of transferring wine from a Secondary into wine bottles with a Racking Hose. The process can be assisted with the use of a Bottling Wand. Usually, Bottling includes corking, affixing capsules, and labeling the bottles.

A stiff plastic tube with a one-way flow valve at the lower end that is used in Bottling. In its simplest form, when the tip is pressed against the bottom of a bottle, wine flows into the bottle. When the tip is lifted, the flow-valve closes and stops the flow of wine.

The complex, vaporous scent(s) released when a bottle is uncorked, derived from volatile esters, ethers and acids formed during aging. Bouquet may rapidly dissipate or be slowly released, but when gone the wine is left with aroma, the fragrance of the fruit the wine was made from.

See Mead

See Mead

A descriptor denoting absolute, crystalline clarity in a wine.

One of several hydrometer or saccharometer scales denoting the density of liquid (must, juice or new wine) in terms of specific gravity. Each degree Brix is equivalent to 1 gram of sugar per 100 grams of liquid. The potential alcohol of a must is estimated by multiplying the Brix reading by 0.55. Both the Brix and Balling scales are comparable and are usually used to finely estimate sugar content.

Sugar crystals coated in a molasses syrup with natural flavor and color. Many sugar refiners produce brown sugar by boiling a special molasses syrup until brown sugar crystals form. A centrifuge spins the crystals dry. Some of the syrup remains, giving the sugar its brown color and molasses flavor. Other manufacturers produce brown sugar by blending a special molasses syrup with white sugar crystals. Dark brown sugar has more color and a stronger molasses flavor than light brown sugar. Lighter brown sugars are more commonly used in winemaking than darker ones, as the richer molasses flavors in the darker sugar tend to mask the bases flavors of the wine, but both have their place.

A glass or plastic device designed to use water as an insulator to protect the fermentation media from contamination and exposure to fresh air, while at the same time allowing carbon dioxide produced by the yeast to escape the fermentation vessel. Also called an air lock, fermentation trap or airlock.

The aging of wines in vats, barrels, casks, demijohns, carboys, or gallon jugs prior to bottling. An advantage of bulk aging is that the wine ages evenly and sediments developed during aging can be left behind when the wine is bottled.

Italian term for grape juice or must boiled down to one third or a quarter of its original bulk and used for the improvement and fortification of young fully fortified wines. In Spain it is called Madre Vino.

Tablets used in winemaking to sanitize equipment and fermentation media and add free SO2 to the must or wine. When crushed and dissolved, they provide sulfur dioxide (SO2) in a convenient form. Tablets must be crushed to use, but this ensures the proper dosage and assists in their dissolution. The active ingredient in Campden tablets can be purchased bulk from most winemaker suppliers under its chemical name, potassium metabisulfite. For sanitizing bottles, primaries, secondary's, funnels and other equipment, two crushed tablets dissolved in 1 gallon of water will suffice. Do not rinse equipment after sanitizing. For adding to must, use one crushed and dissolved tablet per gallon of must and wait 12 hours before adding yeast. Campden tablets come in various sizes and doses, so inquire if not packaged with instructions. Most tablets are intended to dose 5 US gallons (19 liters) or 5 Imperial gallons (23 liters). Also see Potassium Metabisulfite and Sodium Metabisulfite.

The layer of fruit pulp, skins, and possibly seeds that forms on top of the must during fermentation in the primary fermentation vessel. The cap forms when carbon dioxide emitted by the yeast rises to the surface, carrying solid material with it. The steady rise of CO2 keeps the solids at the surface where they form a "cap." The surface of the cap should not be allowed to dry out, as it is a perfect medium for mold growth. One should "punch down the cap" at least daily, but preferably twice a day. This keeps the cap moist and, by submerging it briefly, coats it with sulfite-bearing wine that kills mold spores (assuming, that is, that the must was treated with Campden tablets or potassium metabisulfite initially).

See Mead

A decorative foil, plastic, or mylar sleeve placed over the cork and neck of a wine bottle.

The taste and/or odor of caramel, achieved by heating a sweet wine. In non-grape wines, this characteristic can be achieved by cooking the fruit to extract the juice, set the color or extract polyphenolic compounds from the skins. It is the browning of sugar that most often produces this character. Juice that is steam extracted usually does not possess this characteristic. The perception of some caramel is desired in some wines (sweet sherries), but considered a fault in most others.

The colorless, odorless gas emitted by yeast during fermentation. During Aerobic Fermentation, the gas fills the Ullage but does not completely prevent desired oxygen from entering the Must. During Anaerobic Fermentation, the gas fills the Ullage but the Air Lock prevents undesired oxygen from entering the must. An Air Lock allows carbon dioxide to escape without allowing oxygen into the fermentation vessel. The chemical shorthand for carbon dioxide is CO2.

A technique for producing light red wines with low tannins, intense color, and fresh, fruity flavors and aromas. This process involves dumping whole bunches of freshly picked, uncrushed grapes into large vats filled with carbon dioxide. The bottom grapes are crushed by the weight of the grapes above them, and fermentation begins with the exuded juice and develops upward. Eventually, fermentation begins within the whole grapes, and they begin to exude more juice. Finally, the whole batch is pressed, and fermentation is finished in a standard way.

A large glass or plastic bottle of 2 gallon capacity or more, with or without handles, and sometimes fitted with a spigot or plastic tubing at the bottom for drainage. Carboys are usually 3-, 5- or 6-gallons, but the author has seen all of the following: 2-gallon, 2.2-gallon, 2.5-gallon, 2.8-gallon, 3-gallon, 5-gallon, 6-gallon, 6.5-gallon, and 7-gallon.

A fining agent made from milk protein.

To add sugar to a must or juice to increase its alcohol potential, or to a new wine to balance the taste of its alcohol or the bite of its acidity or tannin. The word is a method named after M. Chaptal, who in 1801 accurately calculated the amount of sugar to add to a wine to achieve balance.

A colorless acid found in all citrus fruit, pineapples, and in lesser amounts in several other fruit.

Properly, the English term for the red wines of Bordeaux, but more commonly the term for any light red wine.

The process of a wine becoming clear, which occurs when all of the yeast and microscopic bits of pulp from the base ingredients of the wine settle to the bottom of the secondary, leaving a clear wine without haze. A wine that has clarified to the nth degree and is crystal clear is called brilliant.

See Mead

A wine that is visually unclear. Cloudiness is considered a severe fault often due to faulty winemaking.

See Carbon Dioxide.

The process of removing excess potassium and tartaric acid under chilled conditions as Potassium Bitartrate to prevent its precipitation in the bottle when chilled.

Multiple layers and nuances of bouquet and flavor that are perfectly balanced, completely harmonious, and delightfully interesting.

Wine bottle closure made from the bark of cork oaks (Quercus Suber). Quality corks have very fine grain, only minor or no faults, good compressibility, and have been cured to contain between 5 and 8% moisture.

A wine that's been affected by a faulty cork, specifically by a chemical compound (2,4,6-Tricloroanisole-246-TCA) that humans can perceive at levels as low as 30 parts per trillion. High levels of this compound produce an unmistakably odor and flavor that many describe as that of moldy, wet cardboard or newspapers. At moderate levels, a corked wine takes on a musty quality; at lower levels, it seems lacking in fruit. Corkscrew:

Device for removing corks from wine bottles. See Wine Openers at Wine Accessories.

A large-mouthed, cylindrical, earthenware vessel, glazed to contain liquid. The best sizes for winemaking are 1-1/2 gallon, 3 gallons, and 6 gallons; these adequately handle the ingredients for any 1 gallon-, 2 gallon-, or 5 gallon-batch recipe.

The sediment thrown off by red wines as they age in bottles--usually associated with sediments in port.

See Diammonium Phosphate.

The process of reducing the amount of titratable acid in must, juice or wine. This is usually done by chemical neutralization, cold stabilization and/or amelioration.

To pour clear wine gently from a bottle into a serving container (decanter or carafe) so as not to disturb its bottle sediments and thereby leave them behind. Also, to allow a wine to "breathe" before serving.

The process of removing dissolved carbon dioxide from a wine to bring it to stillness. Vigorous stirring and applying a vacuum are the two most common ways of achieving this.

A light brown sugar with large golden crystals which are slightly sticky. While this sugar is often expensive, it has a unique, unmatched flavor.

The French term denoting "semi-sweet" and indicating a wine as neither dry nor sweet, but closer to sweet than dry. Although usually reserved for sparkling wines, it is gaining frequent use describing still wines. A wine is usually perceived as demi-doux when its specific gravity is in the range of 1.004 to 1.007.

A large-bodied, small-mouthed, long-necked wine bottle, usually covered with wicker, used to store wine or as a secondary fermentation vessel. Demijohns come in many sizes, including 5-, 10-, 15-, 20-, and 25-gallon (Imperial).

The French term denoting "semi-dry" and indicating a wine as neither dry nor sweet, but closer to dry than sweet. Although usually reserved for sparkling wines, it is gaining frequent use describing still wines. A wine is usually perceived as demi-sec when its specific gravity is in the range of 1.000 to 1.003.

A still wine type that is both sweet and high in alcohol and usually served after a meal or with a dessert. Dessert wines typically have 17% to 22% abv. Port and Sherry are the two best known dessert wines, but others include Madeira, Malaga, Marsala, Muscatel, and Tokay.

One of the major ingredients in almost all yeast nutrients and energizers, serving as their basic source of nitrogen. Also known as DAP.

A still wine, usually light to medium in body, dry to semi-dry, low to moderate in alcohol (10% to 13% by volume), and often served with meals. Also called table wine.

The process of removing the sediment from the bottle during the method champenoise process of making fine sparkling wines. In the previous step, called remuage, sediment slowly collects around the cork as the bottle is positioned upside-down. The neck of the bottle is then placed in an icy brine, which causes the neck's contents to freeze into a solid plug. During disgorgement the cork or cap is carefully removed, and the pressure in the bottle causes the frozen plug of sediment to pop out.

A syrupy mixture of sugar and wine that's added to still wine, along with yeast, to fuel a secondary fermentation in the bottle to make champagne and other sparkling wine.

The French word for "sweet," which in wine is usually perceived when residual sugar is at or above a specific gravity of 1.008.

A wine lacking or deficient in residual sugar. A wine becomes dry when all or most of the sugar within it has been converted through fermentation into alcohol and carbon dioxide. A wine is usually perceived as dry when residual sugar is at or below a specific gravity of 0.999.

The unpleasant odor of damp soil that is perceived in the mouth. Most wines made from roots (beet, carrot, parsnip, rutabagas, turnip) possess an earthy quality that diminishes to neutral over time -- usually two years, but possibly more -- and should not be served until neutralized by age. Whenever perceived, it is a fault.

An excess of dissolved carbon dioxide in a wine. The French have a more precise terminology for degrees of effervescence than does English:

• Tranquille means a still wine

• Perlé is a lightly effervescent wine

• Pétillant is a mildly effervescent wine

• Mousseux is a sparkling wine, such as Champagne

See Yeast Energizer.

The science and study of winemaking, also spelled oenology.

Any of numerous protein molecules produced by living organisms (including yeast) and functioning as catalysts in biochemical reactions. Despite their derivation from living materials, are not living organisms themselves. Enzymes emerge intact from the catalytic reactions they produce and are denatured (rendered inactive) by pH extremes and high temperatures. Usually, an enzyme acts only on a specific molecule (substrate), so an enzyme that acts upon pectin will not act upon starch. In winemaking, most of the essential enzymes are produced by yeast, but some are not and must be introduced by the winemaker. Some of the more important enzymes that find use in winemaking are:

• Amylase: An enzyme that catalyzes the hydrolysis of starch into maltose and dextrin.

• Cellulase: Any of several enzymes that catalyze the hydrolysis of cellulose.

• Invertase: An enzyme that catalyzes the hydrolysis of sucrose into an equal mixture of glucose and fructose.

• Lactase: An enzyme that catalyzes the hydrolysis of lactose into glucose and galactose.

• Lipase: Any of a group of enzymes that catalyze the hydrolysis of triglycerides into glycerol and fatty acids.

• Maltase: An enzyme that catalyzes the hydrolysis maltose to glucose.

• Pectinase: An enzyme that catalyzes the hydrolysis of pectin to pectic acid and methanol.

Volatile oils that impart distinctive odors or flavors which, in wine, combine with alcohol and contribute to its bouquet.

Volatile, aromatic, organic compounds formed by the chemical interaction of the wine's alcohol, acids and other components during maturation.

An "oven" or heating chamber used in the estufagem process for making Madeira or Sherry.

A winemaking process peculiar to the making of Madeira and sometimes used in the making of Sherry. This process consists of heating the otherwise finished wine in an "oven" (estufa) for a prolonged period. This can range from 90-100 degrees F. for a year to 140 degrees F. for 3 months, with the lower temperatures yielding a better wine. The wine is then racked into wood and aged for 1-3 years.

An alcohol, C2H5OH, produced by distillation or as the principal alcohol in an alcohol fermentation by yeast. Also know as Ethyl Alcohol.

An ester produced by fermentation. When ethyl acetate exists in sufficient quantity, it produces a slightly sweet, fruity, vinegary smell. Too much is considered a flaw.

Descriptor for a wine that has suffered insipient oxidation -- i.e. has passed its prime and is declining in quality.

The process of yeast acting upon sugar to produce alcohol and carbon dioxide.

Sometimes called the secondary fermentation vessel, a fermentation bottle is a shouldered, small-mouthed glass jug or carboy in which the liquor or juice is placed to complete fermentation under a fermentation trap.

The pulp or other solid material from which wine will be made. Fermentation media differs from must in that the must is the media, the water, the yeast, and all other ingredients mixed together, while the fermentation media more narrowly refers to the crushed grapes, chopped raisins, pulped peaches, cracked wheat, or other material used either for flavoring, natural sugar content, or both. It is also called the base ingredient or wine base.

A glass or plastic device designed to use water as an insulator to protect the fermentation media from contamination and exposure to fresh air, while at the same time allowing carbon dioxide produced by the yeast to escape the fermentation vessel. Also called an air lock, bubbler or airlock.

The practice of planting a vineyard with several grape varieties which are harvested together and all contribute to a common wine. Similarly, the mixing of grapes before the crush to constitute a field blend must.

The process of removing yeast cells and other microorganisms that could spoil the wine, as well as any remaining sediment that would keep it from being crystal clear, by pumping the wine through cellulose pads, pads lined with diatomaceous earth, or especially fine membranes.

Removing suspended solids from a cloudy wine by temperature adjustment, blending with an already cleared wine of the same variety, filtering, or adding a fining material such as egg white, milk, gelatin, casein, or bentonite.

The final flavor, texture and impression that remains on the palate after a wine is swallowed.

Those acids occurring naturally in the grape or fruit base, those added by the vintner, and those acids created furing fermentation which are stable -- fixed. In grapes and grape wine, the major fixed acid is tartaric, followed by malic, then citric, succinic, and lactic, although the latter three are not necessarily listed in the order of their prominence in the finished wine as they can vary greatly. Succinic, for example, is usually more naturally prominent in grape wines than citric.

A taste denoting a wine with insufficient total acidity. The taste is truly flat, lifeless, medicinal, and wholely wrong. Technically, it is the absence of the sour taste. This taste appears in wines with a pH greater than 3.75 and a titratable acidity less than 0.5%. The opposite (the taste of excessive total acidity) is Acidulous.

The process of settling or compacting of lees or sediment. Lightly or loosely flocculated lees are less dense than tightly or compactly flocculated ones. Good flocculation refers to greater density.

Spanish word for "flower" which refers to the off-white yeast that develops naturally on certain wines after they're fermented and blocks further exposure of the wine to air. Flor is important in the making of fino- and amontillado-style sherries. Flor will not grow on wines with more than 16% alcohol.

The process of adding distilled spirits to a finished wine to increase its alcohol content, improve its preservation qualities, or improve its flavor. Brandy is often used as a fortifying agent because it is made from wine, but vodka, gin, Everclear, or any distilled spirit may be used. Each fortifying agent has its own flavor and will impart this to the fortified wine.

The odor and taste of methyl anthranilate and/or ethyl anthranilate and in wine exclusively associated with wines made from grapes with a Vitis labrusca parentage or ancestry. The pleasant and unpleasant odors and tastes associated with other native grapes, without Vitis labrusca ancestry, should not be termed "foxy."

Sulfur dioxide ions in solution in must, juice or wine that are not chemically bound to other chemicals in solution and thus are free to react with such substances as acetalhyde or oxygen or to escape the must, juice or wine as a gas molecule.

Italian term for a mildly carbonated wine causing a slight sensation on the tongue, but enough carbonation to produce bubbles in the glass the way Champagne or other sparkling wines do. Pétillant is French and synonymous.

A wine with carbonation, usually produced by a secondary fermentation in the bottle, but also unexpectedly and unintentionally produced by malo-lactic (bacterial) or alcohol (yeast) fermentation.

A fault caused by sorbic acid degeneration, characterized by the odor of geraniums. The offending compound is 2-ethoxy-hexa-3,5-diene.

One of two simple fermentable sugars in grapes and other fruit, the other being fructose. Glucose is approximately half as sweet as fructose.

See Glycerol.

A colorless, odorless, slightly sweet, syrupy substance produced naturally during fermentation that gives the palate an impression of smoothness in a wine. Also known as glycerine.

A long bag of finely woven net-like material (mesh) used for suspending grain or other fermentation media in liquid during fermentation to ease the removal of the solids later. Grain-bags come in various mesh and sizes and can be used in lieu of a jelly-bag for straining the solid fermentaion media from the wine.

An odor of wine made from unripe grapes and often associated with high acidity. The term "green," however, is just confined to the odor.

A relatively clear wine that has a moderate amount of suspended particulates. Not quite as severe a fault as cloudiness.

The process of removing excess protein to preserve a wine's clarity when stored under warm conditions. Heat stabilization is usually performed with a Bentonite fining.

An odor suggestive of herbs or broken green stems of plants. It is a positive characteristic is suggestive of the base and not too pronounced, but a fault if excessive or from spoilage.

See Mead

A wine with excessive alcohol that creates a burning, prickly sensation in the mouth and throat.

H2S for short, Hydrogen sulfide is produced in all wines by yeast combining with various forms of sulfur, but in excess creates an undesirable, rotten-egg-like smell in wine. If not corrected, the wine is ruined as the gas is transformed into mercaptans, with a skunky odor, and then disulfides, with a sewage smell.

See Mead

An instrument for measuring the specific gravity (abbreviated as s.g.), relative to sugar content, of a liquid. The importance of s.g. rests in it's indication of proofing potential. In other words, s.g. indicates how much dissolved sugar is present for conversion to alcohol by yeast, what that proof will be, and how much sugar to add to raise the finished proof to a specific level. A hydrometer which indicates the proof of the present alcoholic content is called a "proofing hydrometer."

A rich, flavorful dessert wine made from grapes frozen on the vine and then pressed them before they thaw. Because much of the water in the grapes is frozen, the resulting juice is concentrated, rich in flavor and high in sugar and acid. The resulting wines are extraordinarily sweet, yet balanced by high acidity.

To add an active, selected culture of yeast or malo-lactic bacteria to a must, juice or unfinished wine.

The product of the hydrolysis of sucrose, which is glucose and fructose. Yeast convert invert sugar more rapidly than sucrose, such as simple cane sugar, because they do not have to break the sucrose down into glucose and fructose themselves. Invert sugar can be made by dissolving two parts sugar into one part water, adding two teaspoons lemon juice per pound of sugar, bringing this almost to a boil, and holding it there for 30 minutes (NOT allowing it to boil). If not to be used immediately upon cooling, this can be poured into a sealable jar, sealed and cooled in the refrigerator. Invert sugar should NOT be used to sweeten finished wine as it will encourage refermentation.

The enzyme yeast use to catalyze the hydrolysis of sucrose to yield an equal mixture of glucose and fructose, yielding invert sugar.

A cylindrical glass or earthenware container with a large mouth and capable of holding liquids, usually without handles.

An enzyme that catalyzes the hydrolysis of lactose into glucose and galactose.

An acid formed in trace amounts during yeast fermentation and in larger quantities during malolactic fermentation, in which bacteria converts malic acid into lactic acid and carbon dioxide. See malolactic fermentation.

Deposits of yeast and other solids formed during fermentation. This sediment is usually separated from the wine by racking. Sometimes the wine is left in contact with the lees in an attempt to develop more flavor. See Autolysis and Sur Lie Aging.

A coating on the inside of the wine glass, after being swirled, that separates into viscous-looking rivulets that slowly slide down the glass to the wine's surface. Legs generally indicate a rich, full-bodied wine.

An enzyme that catalyzes the hydrolysis of triglycerides to yield glycerol and fatty acids.

The period of time grape juice spends in contact with the skins and seeds.

French term applied to a big, heavy wine with great lasting properties.

French term for wine,which 1s old, woody and oxidized. American spelling is "maderize."

Spanish for Mother Wine, grape juice or must boiled down to one third or a quarter of its original bulk and used in parts of Spain and France for the improvement and fortification of young fully fortified wines. In Italy it is called calamich.

A naturally occurring acid found in apples, cherries, grapes grown in less sunny regions, and certain other fruit. It is the presence of malic acid, along with Bacillus gracile, which sometimes produces malo-lactic fermentation.

MLF for short, this is a bacterial fermentation which can occur after yeast fermentation winds down or finishes. The bacterium Bacillus gracile converts malic acid into lactic acid and carbon dioxide. Lactic acid is much less harsh than malic and thereby softens and smooths the wine, but the wine also is endowed with a cleaner, fresher taste. In addition, diacetyl (or biacetyl) is produced as a byproduct, which resembles the smell of heated butter and adds complexity to wine. MLF is a positive event in some cases and has a downside in others--the fruitiness of wines undergoing MLF is diminished and sometimes off-odors can result. To ensure MLF, the wine should not be heavily sulfited and it should be inoculated with an MLF culture. If MLF occurs after bottling, it produces a slightly carbonated wine which may or may not be appreciated.

An enzyme that catalyzes the hydrolysis maltose to glucose.

The process of aging in bulk or in bottles or both, to achieve smoothness (in acidity), mellowness (in tannins and other phenols) and unique character and complexity. The major activities in this process are the chemical reduction of certain compounds into others, primarily by hydrolysis or oxidation, and the joining together of short molecular chains into longer ones. Volatile esters, ethers and acids create bouquet, which is not the same as aroma.

See Mead

The skunky odor of methyl and ethyl sulfides.

Synonym for methyl alcohol, found in very small traces in wine and produced during fermentation.

Denatured alcohol. Used to check if a haze is pectin in origin. Add 3-4 fluid ounces of methylated spirit to a fluid ounce of wine. If jelly-like clots or strings form, then the problem is most likely pectin and should be treated with pectic enzyme.

See Campden Tablets, Potassium Metabisulfite or Sodium Metabisulfite.

See Mead

See Mead

A powered or manual device for chopping fruit, grain vegetables, or meats into very small pieces. The size of the pieces can usually be regulated by changing chopping blades. This device is very useful for chopping large quanties of fruit, especially dried fruit and raisins.

See Mead

French for biting. A wine which has a trace of bitterness, plus acidity, plus a tiny prickliness on the palate. In a blend, however, a mordant wine can improve a weak wine, although its pungent characteristic will come through.

French term for highly effervescent wine. Also see Sparkling Wine.

French for flabby. A wine which lacks body and sprightliness -- one which has little alcoholic strength and tannin.

French word is used to denote a wine which is releasing a tiny amount of carbonic gas, due to an extremely light secondary fermentation. If purposely made, it is labelled as such, as in "Moustille Sauvignon Blanc." Served chilled on hot afternoons, it is a refreshing drink.

An disagreeable odor in wines made from late-harvested grapes or low-acid musts and caused by bacteria.

See Mead

A British specialty brown sugar, very dark brown, with a particularly strong molasses flavor. The crystals are slightly coarser and stickier in texture than "regular" brown sugar. Also know as Barbados Sugar.

The combination of basic ingredients, both solid and liquid, from which wine is made. The liquid content of must is called liquor or simply juice, while the solids, when pushed to the surface by rising carbon dioxide, is called the cap. When the alcohol content reaches 8 or 9%, the liquid component is more accurately referred to as wine.

French for stopping fermentation.

A partially fermented grape juice whose fermentation has been stopped deliberately. This juice is then used to sweeten or body-fortify another wine.

The smell of a wine, combining both its aroma and bouquet, thereby revealing the character of the base from which it was made and the character of its maturation.

The process of immersing oak chips, shavings, particles, cubes, "beans," or sticks into a wine to simulate having aged the wine in an oak barrel or keg. The oak may be natural or it may be toasted (light, medium or heavy toast). Oaking allows young wines to soften and absorb some of the wood's flavors and tannins. However, most light, delicate wines should not be oaked.

A proprietary product containing potassium bicarbonate in a premeasured amount and used for acid reduction. Use only as directed by the manufacturer.

An unexpected, nondistinct, slightly offensive odor or taste in a wine and considered a minor fault.

German standard scale for fixing a wine's sugar content.

The science of winemaking; from the Greek oinos, wine.

See Mead

A wine having no vices and no virtues. Applied to vins du pays, usually natural wines without any fortification.

The process of reaction between many molecular components of wine with oxygen, resulting eventually in in a darkening (browning) of the wine and the development of undesirable odors and flavors.

The process of killing bacteria by heating wine or must to moderately high temperatures for a short period of time and then rapidly cooling it to 40°F or lower.

French for pasty, sticky. A wine of thick substance which fills the mouth and seems to stick to the palate.

The enzymes such as pectinase that hydrolyze the large pectin molecules.

A heavy, colloidal substance found in most ripe fruit which promotes the formation of gelatinous solutions and hazes in the finished wine. Fermenting fruit pulps with high pectin content, such as apples, should be treated with pectic enzyme, especially if the pulp is boiled to extract the fruit flavor (boiling releases the pectin, while pectic enzymes destroy it).

An enzyme that catalyzes the hydrolysis of pectin molecules.

A spicy odor sometimes found in white table wines and perhaps related to sub-threshold sulfur dioxide. Not considered a fault unless excessive.

French term for a lightly effervescent wine, less than pétillant. Mead

See Mead

French term for a mildly effervescent wine causing a slight sensation on the tongue, but not enough carbonation to produce bubbles in the glass the way Champagne or other sparkling wines do. Frizzante is Italian and synonymous.

A chemical shorthand for [p]otential of [H]ydrogen, used to express relative acidity or alkalinity in solution, in terms of strength rather than amount, on a logarithmic scale. A pH of 7 is neutral; above 7 is increasing alkalinity and below 7 is increasing acidity. Thus, a pH of 3 is 10 times more acidic than a ph of 4. See Acidity.

French for a wine which has a slight tendency towards turning to vinegar, and / or a wine which is showing a secondary fermentation. Strictly speaking, it is a purely tactile sensation which is noticed when the wine touches the mouth.

The residue of pressed pulp, skins and pips of apples, grapes or any fruit after pressing. When pressed under great pressure, a pomace cake or brick results. Pomace from appropriate fruit can be ameliorated with sugar, acid, water, and yeast nutrients (possibly acid and tannin will also be required) and a second wine can be made. The pomace provides enough flavor for a reduced volume of wine and should contain enough viable yeast (assuming the pulp was pressed after an initial period of fermentation) to continue fermentation.

Strictly soeaking, a wine made in an area of the Douro Valley, Portugal, 50 miles inland from the port town of Oporto. The name is an abbreviation of the Portuguese name Vinho do Porto or wine of Oporto. More generally, a type of wine made in the style of Port. The wine is commercially made by adding sufficient brandy at the time of fermentation to bring the strength up to some 18 percent alcohol. This is sufficient to stop further natural fermentation, which means that the wine remains sweet. After aging several years, more brandy is added to bring the alcohol up to 20-22%. Port styles are:

• Tawny Port: a light reddish-brown colored wine, either a blend of red and white port or a single wine of one year and one vineyard which has become russet coloured through great age in wood.

• Ruby Port: a full, deep coloured, blended wine.

• White Port: made with white grapes. Sometimes the Muscatel grape predominates, in which case the wine takes on this flavour.

• Late Bottled Vintage: least known port, but according to many experts it combines the best qualities of vintage and tawny ports. These wines are produced by keeping a vintage port for 8 to 15 years and then bottling it for a further period of 5 years.

• Vintage Port: when a year is extra good and produces a sufficient quantity, shippers may decide to declare a vintage, or declared year. The port is shipped unblended (as with tawny and ruby) to Britain to be bottled in that country in the October, November or December exactly two years after the vintage.

A salt of potassium and tartaric acid which can precipitate out of a wine as crystals under chilled conditions.

One of two compounds which may be used to sanitize winemaking equipment and utensiles (the other being sodium metabisulfite). Potassium metabisulfite is the active ingredient in Campden tablets. Its action, in water, inhibits harmful bacteria through the release of sulfur dioxide, a powerful antiseptic. It can be used for sanitizing equipment and the must from which wine is to be made. For equipment, a 1% solution (10 grams disolved in 1 liter of water) is sufficient for washing and rinsing. After using the solution, the equipment should not again be rinsed. For sanitizing the must, a 10% solution is made (100 grams dissolved in 1 liter of water). Three milliliters of this 10% solution added to a U.S. gallon of must will add approximately 45 ppm of sulfur dioxide (SO2) to the must. One should wait at least 12 hours after sanitizing the must before adding the yeast. Both bottles of solution (1% and 10%) should be clearly labled as to strength and active compound to prevent disasterous mistakes, and both may be stored in a cool place for up to one year without effecting potency. Also see Campden Tablet and Sodium Metabisulfite.

Also known as "Sorbistat K" and affectionately as "wine stabilizer," potassium sorbate produces sorbic acid when added to wine. It serves two purposes. When active fermentation has ceased and the wine racked the final time after clearing, 1/2 tsp. added to 1 gallon of wine will render any surviving yeast incapable of multiplying. Yeast living at that moment can continue fermenting any residual sugar into CO2 and alcohol, but when they die no new yeast will be present to cause future fermentation. When a wine is sweetened before bottling potassium sorbate is used to prevent refermentation. It should always be used in conjunction with potassium metabisulfite (1/4 teaspoon per 5 gallons of wine or 1 crushed and dissolved Campden tablet per gallon) and the wine will not be stabilized without it. It is primarily used with sweet wines and sparkling wines, but may be added to table wines which exhibit difficulty in maintaining clarity after fining. Also see Sodium Benzoate and Wine Stabilizer.

The potential amount of alcohol that can be expected from a given must based on its measured specific gravity. See Brix and Specific Gravity.

To use pressure to force juice out of fruit pulp, or a device used to achieve this result.

A crock, bowl, bucket, pail, or other non-reactive, food-safe vessel in which the initial, or primary fermentation takes place. The primary should be capable of containing 1/4 to 1/2 more volume than the volume of the must it will contain to allow for a rising of the cap and a sufficient ullage above the cap to allow a good aerobic fermentation. Thus, a 1-1/2 gallon pail is about right for a 1-gallon batch of wine, although a larger vessel is okay. Typically, the primary has a large mouth to allow easy access. It should be covered during fermentation to prevent dust and airborne bacteria, molds and wild yeast from blowing into it, but should not be air-tight. Also known as the primary fermentation vessel.

The initial, main alcohol fermentation by yeast. It is usually begun by adding an active yeast starter to a must or juice in a covered primary fermentation vessel, but may begin spontaneously from wild yeast on the grapes or fresh fruit base. After a period of vigorous fermentation, the must is pressed or strained and/or the juice is transferred to a secondary fermentation vessel (e.g. a carboy or demijohn) and covered by an airlock. Even though the wine is now in a secondary fermentation vessel, the alcohol fermentation taking place is a continuation of the primary fermentation. See Secondary Fermentation for contrast.

A crock, bowl, bucket, pail, or other non-reactive, food-safe vessel in which the initial, or primary fermentation takes place. The primary should be capable of containing 1/4 to 1/2 more volume than the volume of the must it will contain to allow for a rising of the cap and a sufficient ullage above the cap to allow a good aerobic fermentation. Thus, a 1-1/2 gallon pail is about right for a 1-gallon batch of wine, although a larger vessel is okay. Typically, the primary has a large mouth to allow easy access. It should be covered during fermentation to prevent dust and airborne bacteria, molds and wild yeast from settling into it, but should not initially be closed air-tight as it is desirous for the must to have exposure to plenty of air during the first 48-72 hours of fermentation. Also known as the primary.

A numeric notation representing the alcoholic content of the spirit. Two degrees proof equals one percent alcohol, so a "36 proof" wine contains 18 percent alcohol. Strictly speaking, "true" proof spirit contains 57.1% alcohol at 60 degrees fahrenheit, the amount of alcohol required, when combined with water, to allow combustion.

The soft, juice-laden flesh of the grape or other fruit.

The process of pushing the cap of skins, seeds and pulp down into the juice during fermentation. This facilitates extraction of color, flavor, and tannins and ensures that the cap doesn't dry out and develop unwanted mold or bacteria.

The hot taste of capsaicin -- the compound in chiles (jalapeno, etc.) that gives them their firey heat -- in a chile wine or mead,

The concave indentation in the bottom of a wine or champagne bottle.

The process of siphoning the wine off the lees to allow clarification and aid in stabilization. A Racking Hose or tubing is used and can be attached to a Racking Cane to make this task easier. An old saying is, "The racking can make a wine."

A stiff, plastic tube, usually "L"-shaped, that is attached to the Racking Hose to make Racking easier. A protective cap is placed over the lower end of the cane that allows liquid to be drawn into the cane from above rather than below while keeping most large solids out. The cap allows the tip of the cane to be lowered close to the lees without unduely disturbing them. The lower tip of the Racking Cane should initially be held about midway between the suface and the lees and gradually lowered as the volume decreases due to the siphoning.

A flexible, clear plastic hose, usually 3/8 inch in inner diameter, used to siphon wine from one vessel to another. It is used in both Racking and Bottling operations.

Literally, to "cover again." When instructions say to "recover starter," to "stir and recover," or to "recover primary," they mean to cover the yeast starter or the primary fermentation vessel in the manner previously prescribed. For example, in Yeast Starter (below) it says, "Cover the jar with a paper towel or napkin held in place with a rubber band." Later in the instructions it says, "...add another 1/4 cup of juice from the must and recover." This means to cover the jar again with a paper towel or napkin held in place with a rubber band.

Adding a fuller, younger wine to an older one in order to give the latter something to prolong its life.

French for moving, stirring, In the making of champagne and other sparkling wines, an operation for shifting the deposit or sediment onto the cork of the bottle. During this operation each bottle is placed neck downwards in a rack which, after the bottle is given a sharp quarter-turn, is tilted gradually until the bottles are perpendicular in the rack and the deposit has settled on the inside face of the cork, at which time it can be disgorged. See Riddling, the American term.

See Mead

The amount of sugar, both fermentable and unfermentable, left in a wine after fermentation is complete or permanently halted by stabilization. Fermentation is complete when either all the fermentable sugar has been converted by the yeast into alcohol and carbon dioxide as byproducts or when the concentration of alcohol produced reaches a level that is toxic to the yeast and they die. Fermentation is permanently halted by stabilization through several means involving intervention by man.

The process of turning a bottle of sparkling wine-in-the-making in a certain way, so as to migrate the lees in the bottle into the neck and against the cork. The bottles are initially tilted downward at a 45-degree angle and every third day are given a slight shake, turned a quarter-turn, and dropped back into the riddling rack. The process takes 6-8 weeks to complete unless extended bottle-aging sur lie is undertaken. See Remuage.

Any pinkish, rose-colored wine made from red grapes by allowing only brief skin contact during the first 2-3 days of fermentation, or even less for a strongly-pigmented juice.

A paper, foil, mylar, or plastic packet of dehydrated, freeze-dried, dried, or active dried yeast. A sachet typically holds 5 grams of product, although 35- to 100-gram sachets of some products are available.

See Mead

An odor in wines, attributed to lactic acid, that have undergone excessive malo-lactic fermentation. This fault is most often found in wines made from malic-dominate bases (such as blackberry) which undergo unchecked malo-lactic fermentation.

French for dry. A wine becomes dry when all or most of the sugar within it has been converted through fermentation into alcohol and carbon dioxide. A wine is usually perceived as dry when residual sugar is at or below a specific gravity of 0.999.

A wine made from the pomace or strained pulp obtained from making a first wine. A second wine will require that the pomace or pulp be ameliorated with water, sugar, yeast nutrients, and possibly acid and tannin, but usually not pectic enzyme. Sulfites, however, should be introduced at once to achieve and unbound sulfur level of 45-55 ppm. A second wine cannot usually be made in the same volume as the original wine from which the pomace or pulp was obtained, but a volume of 1/3 to 2/3 the original is usuallly attained.

A jug, jar, bottle, demi-john, or carboy in which the second phase of alcohol fermentation takes place (the first phase is the primary phase). This vessel typically has a wide body and tapered neck leading up to a small opening which can be sealed with an air lock. Also known as the secondary fermentation vessel.

A second alcohol fermentation by yeast performed in a champagne bottle secured with a special, hollow closure secured with a wire "cage," the purpose of which is to trap the carbon dioxide produced by the fermentation and force it to be absorbed into the wine, or a bacterial fermentation called malolactic fermentation. The result is a Sparkling Wine. This secondary fermentation can actually be a continuation of the fermentation by the original yeast inoculation or can be induced at bottling time by inoculating a sweetened still wine with a second yeast especially adept at fermenting under pressure. It is NOT correct to refer to the alcohol fermentation in a secondary fermentation vessel (e.g. a carboy) as a secondary fermentation although novices to the hobby often do. See Primary Fermentation for contrast. However, a malolactic fermentation is correctly a secondary fermentation.

A jug, jar, bottle, demi-john, or carboy in which the second phase of fermentation takes place. This vessel typically has a wide body and tapered neck leading up to a small opening which can be sealed with an air lock. Also known as the secondary.

The grainy, bitter-tasting deposit sometimes found in bottles of older wines. Sediment is the natural separation of bitartrates, tannins, and color pigments that occurs as wines age and may indicate a wine of superior maturity. Also known as Crust, especially in port wines.

The term denoting a wine as neither dry nor sweet, but closer to dry than sweet. Although usually reserved for sparkling wines, it is gaining frequent use describing still wines. A wine is usually perceived as semi-dry when its specific gravity is in the range of 1.000 to 1.003. The French call such wine demi-sec, which has been bastardized into the half English, half French semi-sec.

See demi-sec and semi-dry.

The term denoting a wine as neither dry nor sweet, but closer to sweet than dry. Although usually reserved for sparkling wines, it is gaining frequent use describing still wines. A wine is usually perceived as semi-sweet when its specific gravity is in the range of 1.004 to 1.007. The French term for this type of wine is demi-doux.

A table wine that has become sherry-like due to oxidation.

An incredibly smooth, lush, and finely textured wine. See Soyeux.

A severe off-odor caused by mercaptan formation. See Hydrogen Sulfide.

See Mead

Sulfur Dioxide. See Sulfite.

Sold as "Stabilizing Tablets," sodium benzoate is used, one crushed tablet per gallon of wine, to stop future fermentation. It is used when active fermentation has ceased and the wine racked the final time after clearing. It is generally used with sweet wines and sparkling wines, but may be added to table wines which exhibit difficulty in maintaining clarity after fining. For sweet wines, the final sugar syrup and crushed tablet may be added at the same time. When using it to stabilize a wine, it must be used in conjunction with an aseptic dose of postassium metabisulfite (1/4 teaspoon per 5 gallons or 1 crushed and dissolved Campden tablet per gallon). Also see Potassium Sorbate and Wine Stabilizer.

One of two compounds commonly used to sanitize winemaking equipment and utensiles, the other being potassium metabisulfite. Its action, in water, inhibits harmful bacteria through the release of sulfur dioxide (SO2), a powerful antiseptic. It can be used for sanitizing equipment, but the U.S. government prohibits its inclusion in commercial wine and thus should not be used to sanitize the must from which wine is to be made. It is about 17.5% stronger than potassium metabisulfite and should be mixed accordingly.

The Spainish system of maintain quality and style consistency in some fortified wines. One-quarter to one-third of the oldest wine is drawn off for bottling and replaced with the next oldest wine, which in turn is replaced with the next-yet oldest wine, and so on until the youngest wine is being used to replace the next youngest wine.

See Potassium Sorbate.

A tart taste in wines, most often associated with acids and ethyl acetate. The degree of sourness in acid is a function of the pH of the wine and its titratable acidity. In technical terms, it is the hydrogen ion (actually, the hydronium ion) that stimulates the sour taste on the taste buds. The order of decreasing sourness og the primary prganic acids in wine are tartaric, malic, citric, lactic, and succinic. Wines with a pH less than 3.1 or a titratable acidity more than 0.9% will taste sour.

French for silky. An incredibly smooth, lush, and finely textured wine. See Soyeux.)

Any wine that has been allowed to complete the final phase of its fermentation in the bottle so that the carbon dioxide produced is trapped within. A carbonated wine, on the other hand, is a still wine that has been artifically carbonated by infusing carbon dioxide into the wine before or during the bottling process. See Still Wine for contrast.

A measure of the density or mass of a solution, such as must or wine, as a ratio to an equal volume of a standardized substance, such as distilled water. Before fermentation, the density of the must or juice is high because sugar is dissolved in it, making it thicker than plain water. As the sugar is converted by the yeast into alcohol and carbon dioxide, the density (specific gravity) drops. A hydrometer measures specific gravity (s.g. for short), with an s.g. of 1.000 being the calibrated density of distilled water at a specific temperature (usually 59 or 60 degrees F.). Because alcohol is actually less dense than water, the finial s.g. of a wine can be less than 1.000, or lighter than water. See Hydrometer.

Beverages with high alcohol content obtained through distillation. Examples are brandy, gin, rum, vodka, and whiskey.

A state attained by wine when all fermentation has ceased at 60 degrees fahrenheit. See Wine Stabilizer, Potassium Sorbate, and Sodium Benzoate.

The process of rendering a wine stable, either naturally or through intervention. See Stable.

A solution of water, juice, sugar, and nutrients into which a culture of yeast is introduced and encouraged to multiply as quickly as possible before adding to a must. The purpose of the starter solution is to achieve a greater density of yeast than contained in the original culture sample so that the cultured yeast will dominate the fermentation process, literally smothering out any wild yeast that might be present. It is also used to restart a Stuck Fermentation. See Yeast Starter for a method of creating a starter solution.

A finished, non-sparkling wine. A finished wine containing no noticeable carbonation. See Sparkling Wine for contrast.

A fermentation that has started but then stops before converting all fermentable sugar into alcohol and carbon dioxide or before reaching the toxicity level of the particular yeast strain(s) involved. A stuck fermentation is usually due to an imbalance in the ingredients or to temperature extremes unacceptable to the yeast.

A natural, crystalline disaccharide found in grapes, most fruit and many plants. This is the type of refined sugar obtained from sugar cane, sugar beets and other sources which, when added to a must or juice to make up for deficiencies in natural sugar, must be hydrolyzed (inverted) into Fructose and Sucrose by acids and enzymes in the yeast before it can be used as fuel for fermentation.

Technically, a salt or ester of sulfurous acid, but more commonly, sulfur dioxide (SO2). Sulfite is the most effective and widely used preservative in winemaking. It preserves by safeguarding musts and wines against premature oxidation and microscopic life forms that could otherwise spoil wine. It preserves a wine’s freshness, helps maintain its color, and is essential for aging wines beyond their first year without deterioriation. It also inhibits wild yeasts, thereby allowing cultured wine yeasts to dominate the fermentation. Sulfites may be "bound" or "free." Bound SO2 combines with aldehyde compounds, those most responsible for oxidation in wines. Free SO2 results from the dissipation of active SO2 and is the only SO2 that provides antiseptic and oxidative protection to wines. The most efficient wat to add free SO2 to a must, juice or wine is by adding dissolved potassium metabisulfite to it. The effectiveness of free SO2 is dependent on the pH of the media to which it is added.

SO2. See Sulfite.

A small, pale golden-green grape originating in Smyrna, Turkey. It is the most widely planted variety in California, where it goes by the name of Thompson Seedless. It is the common "white" or "golden" raisin sold in America.

French for "on the lees", this is the process of leaving the lees in the wine for a few months to a year, accompanied by a regime of periodic stirring. Certain wines such as chardonnay or sauvignon blanc benefit from autolysis because they gain complexity during the process that enhances their structure and mouthfeel, give them extra body, and increase their aromatic complexity. Aging sur lie with lees stirring can result in a creamy, viscous mouthfeel. See Autolysis and Lees.

A sample of the original juice from which a wine is made, used to sweeten the finished wine after fermenting to dryness and stabilized. The sweet reserve is either refrigerated or frozen until needed. When making a sweet reserve from whole fruit, such as strawberries, peaches, or plums, the fruit must be crushed and pressed and the juice stood in a tall, clear, glass bottle in a refrigerator until the juice separates (i.e. pulp sediment settles to the bottom of the bottle). The clear juice is very carefully racked off the sediment and stored for the reserve. The sediment can be lightly pressed through a double layer of sanitized muslin cloth and the liquid obtained allowed to separate out again, with the clear juice again removed and stored with the sweet reserve. The advantage of using a sweet reserve to sweeten a stabilized dry wine is the it adds sweetness, fresh flavor, and natural aroma to the wine. It may also improve the color of the finished wine somewhat.

See total acidity.

A still wine, usually light to medium in body, dry to semi-dry, low to moderate in alcohol (10% to 13% by volume), and often served with meals. Also called dinner wine.

Tannic acid, essential for good aging qualities and balance, gives most wines their "zest" or "bite." Tannin is found naturally in the stems, skins and pips (seeds) of most red and dark fruit such as grapes, elderberries, sloes, apples, and plums, but also in pear skins, oak leaves, and dark tea leaves. Most grains, roots and flowers used in winemaking lack any or sufficient tannin, so must be supplemented with grape tannin or tannin from another source. Wines containing too much tannin can be ameliorated by adding a little sugar or glycerine, fined with gelatine, or blended with another, softer wine.

Proprietary product that contains potassium metabisulfite, ascorbic acid and tannin in premeasured amounts. The ascorbic acid is supposedly used to increase the effectiveness of sulfite (SO2). Actually, research has shown that SO2 protects wine better without ascorbic acid present. Use only as directed by the manufacturer. See Acsorbic Acid and Tannin.

A reddish acid found in grapes and several other fruit.

A sensory perception almost totally localized on the tongue. Although there is some dispute over this, we most often perceive only four basic tastes -- sweetness, sourness, bitterness, and saltiness. The latter is seldom encountered in wines. The flavors perceived in wines are most often integrations of both odor and taste and can be often be altered by pinching the nose tightly and sipping the wine. Still, the loss of odors through evaporation can affect taste by concentrating a certain characteristic, such as sourness of certain acids.

See Mead

The impression on the palate delivered by dense, intense, and full-bodied wines.

A wine lacking body. A wine with a viscosity approximately the same as water.

Also called TA and sometimes total acidity, titratable acidity is the sum of the fixed and volatile acids present in a wine. This is determined by a chemical process called titration. The titratable acidity is usually expressed in terms of tartaric acid, even though the other acids are also measured. Titratable acidity is expressed either as a percentage or as grams per liter. For example, 0.7% TA is the same as 7 grams per liter (or 7 g/l) TA.

To add liquid (finished wine of the same type, grape juice, sweetened water, or plain water) to a wine after racking it to replace any volume lost in the sediments left behind. One can also top up by adding sanitized marbles or glass pebbles to the carboy, thereby displacing the lost volume.

See Titratable Acidity.

See Mead

The air space between the surface of the wine and the bottom of the bung, cork or other closure. In a cask or barrel, it is the volume of wine missing, which if present would result in a full container of wine.

See Volatile Acidity.

See Mead

Technically, any wine made from a single variety of grape (e.g. Cabernet Sauvignon, Zinfandel) or non-grape base (e.g.Santa Rosa Plum, Navajo Blackberry).

"Sour wine," caused by vinegar-producing bacteria, most notably acetobacter. These bacteria are principally airborne, but are also carried by the so-called vinegar fly.

Those acids created during fermentation or reduction processes (aging) which are not stable; they can be altered through further reduction or by evaporating from the wine altogether. Acetic acid and Butyric acid are the two most notable volatile acids in wine and contribute wholly or largely to the wine's volatile acidity and partially to its bouquet.

Specially designed glassware for enjoying wine, characterized by bowls or flutes on stems. Quality wine glasses are designed to capture and hold a wine's bouquet and are ideally shaped and angled to present the wines properly, according to style. See Wine Glasses at Wine Accessories.

Potassium sorbate, also known as "Sorbistat K," which produces sorbic acid when added to wine. When active fermentation has ceased and the wine racked the final time after clearing, 1/2 tsp. added to 1 gallon of wine will prevent future fermentation. Sodium benzoate, sold as "Stabilizing Tablets," and Potassium Sorbate, are other types of fermentation inhibitors. These are primarily used with sweet wines and sparlking wines, but may be added to table wines which exhibit difficulty in maintaining clarity after fining. For sweet wines, the final sugar syrup and stabilizer may be added at the same time. Also see Potassium Sorbate and Sodium Benzoate.

Any mixture of the thousands of yeast strains which may be airborne or on the fruit, exclusive of the cultured wine yeast deliberately added to a must. Grapes, fruit and the air often contain spoilage bacteria, molds or yeast which can destroy a wine's quality, but if no spoilage yeast or bacteria are present in the must the fermentation can produce an acceptable wine. Due to the risk from spoilage organisms, prudent winemakers treat their must with an aseptic dose of sulfite to kill non-yeast organisms, stun wild yeasts into temporary inactivity, and thereby allow their own choice of cultured yeast to dominate the fermentation.

Yeast cultured especially for winemaking, with such desirable attributes a as high alcohol tolerance, firmer sediment formation, and less flavor fluctuation. Wine yeasts are usually obtained from a winemaking/brewing specialty shop or by mail order. See entry for Yeast on starting a culture before adding to must.

This is the process of maturing wine in barrels or casks prior to bottling. This process allows young wines to soften and absorb some of the wood's flavors and tannins and allows the wine's flavors to become concentrated through slight evaporation through the wood. While oak is the overwhelming wood of choice for wood aging, mesquite, hickory, pecan, apple, orange, and cherry wood can also contribute unique qualities to wines aged with their chips or shavings. The taste a wood tends to impart in wine is that of its smell. Also see Oaking.

A unicellular fungi, principally of the genus Saccharomyces, capable of fermenting carbohydrates. Before adding yeast to a liquor or must to initiate active fermentation, it should be "started." After mixing the primary ingredients, but before adding crushed Campden tablet or other sterilizing compound to the must, set aside one cup of the liquor or juice into which the yeast nutrient (or energizer) is dissolved. Add 1/2 to one tsp. yeast, stir gently, and allow to sit, covered with a clean towel or cloth, in a warm place. Allow the culture to "bloom" (grow) a total of 24 hours since adding Campden to the must. Then add this cup of yeast culture to the must, stir and cover, and allow the yeast to "do its thing."

An extraordinary nutrient, energizer is useful when making wines of high alcoholic content (over 14%) and to restart fermentation when the secondary fermentation seems "stuck." Yeast energizer contains many ingredients not found in normal nutrient, such as Riboflavin and Thiamine. The energizer is best used by dissolving 1/2 tsp. in 1/2 to 1 cup of the must or wine before adding. If the fermentation is truly "stuck" and not simply run out, the energizer may be dissolved in 1/4 cup must or wine and 1/2 cup warm (75 degrees F.) water and a pinch of fresh wine yeast added and allowed to bloom under cover over a 12-hour period. An additional 1/4 cup of wine or yeast is then added and the yeast given another 12 hours to multiply before the enriched solution is added to the fermentation bottle.

Food for the yeast, containing nitrogenous matter, yeast-tolerant acid, vitamins, and certain minerals. While sugar is the main food of the yeast, nutrients are the "growth hormones," so to speak.

While "zest" is a quality a good, fresh wine might possess, when mentioned as an ingredient in the recipes on this site, zest refers to the grated rind of lemon, orange, grapefruit, or lime. Only the colored portion of the rind is used, as the white pith is bitter and will spoil the batch. When a recipe calls for 2 lemons, both the zest and the extracted juice are intended unless otherwise stipulated.

The name given to the group of enzymes which yeast use to transform sugar into alcohol.