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Winemaking Terms A to C

Monday, April 03, 2006

I'm fiquring that most people that visit this site have a limited knowledge of making wine.  You'll hear people throwing around terms about making their wines and you have no clue what they are saying.  Hey, don't feel bad, I was in your shoes not too long ago.  So, to help you out, all of this week's posts will be on winemaking terms.

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.

Acetic Acid:
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 acetification 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 acetification was successfully halted.

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

Acid Blend:
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.

Activated Yeast:
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. 

Active Dry Yeast:
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 billiob 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.

Aerobic Fermentation:
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.

Air Lock:
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 Madiera, Sherry, Port, or are typed as Aperitif or Dessert Wines.

Alcohol by Volume:
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.

Anaerobic Fermentation:
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.

Ascorbic Acid:
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 acuality, 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 tastebuds of the tongue.

The decomposition of dead yeast cells that can be favorable or unfavorable, depending on the wine, the yeast, and the process involved. The favorable process can occur in wines that are aged sur lie ("on the lees"). 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 is usually done with an accompanying regime of periodic lees stirring that can result in a creamy, viscous mouthfeel. 

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 correectly 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 ususally used to finely estimate sugar content.

Barbados Sugar:
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 tastebuds 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. Oftens, but not always, a waxy substance on grape, plum, cherry, and apple skins containing the same substances.

Blow-off Tube:
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.

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 ligh-bodied wine such as Bordeaux is easily swallowed. A thin or "watery" wine lacks body altogether.

Bordeaux Blend:
Blended wines made with two or more of the traditional Bordeaux grape varieties. Bordeaux red grapes are Cabernet Franc, Cabernet Sauvignon, Carmenere, Gros Verdot, Malbec, Merlot, Petite Verdot, and St. Macaire; Bordeaux white grapes are Sauvignon Blanc, Muscadelle, and Sémillon.

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

  • Third-Bottle: 250 ml

  • Half-Bottle: 375 ml

  • Pot: 500 ml (Beaujolais table bottle)

  • Clavelin: 620 ml (Jura bottle)

  • Bottle: 750 ml

  • Magnum: 1.5 litres

  • Tregnum: 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)

  • Soverign: 50 litres

Bottle Aging:
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.

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

Bottle Sickness:
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.

Bottling Wand:
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.

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 equavalent 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 ususally used to finely estimate sugar content.

Brown Sugar:
Sugar crystals coated in a molasses syrup with natural flavor and color. Many sugar refiners produce borwn 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.

Bulk Aging:
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.

In cooperage, a wooden stopper used to seal the cask, keg or barrel. In glassware, usually a rubber stopper used to seal a demijohn, carboy or jug. Bungs may be either solid or drilled with a central hole to accept a fermentation lock (airlock). Some bungs have two holes drilled to accept two airlocks, or one airlock and a blow-off tube

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.

Campden Tablets:
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, secondaries, 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). 

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 pefect medium for mold growth. One should "punch down the cap" at least daily, but preferrably 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).
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.

Carbon Dioxide:
The colorless, ordorless 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.

Carbonic Maceration:
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.

Citric Acid:
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.

A wine that is visually unclear. Cloudiness is considered a severe fault often due to faulty winemaking.
Cold Stabilization:
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 compressability, and have been cured to contain between 5 and 8% moisture.

Corked Wine:
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.

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.

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