Copy of `Jack Keller - Wine making glossary`

The wordlist doesn't exist anymore, or, the website doesn't exist anymore. On this page you can find a copy of the original information. The information may have been taken offline because it is outdated.

Jack Keller - Wine making glossary Category: Agriculture and Industry Date & country: 28/10/2013, UK Words: 235

Bloom
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.

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.

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 S

Blending
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.

Bitterness
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.

Bitartrates
Shorthand for potassium bitartrate crystals, the potassium salt of tartaric acid. See Potassium Bitartrate.

Bentonite
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.

Base
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.

Balling
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.

Balance
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.

Aperitif
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.

Aroma
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.

Attenuation
This is the percentange of sugars that yeast consume during alcoholic fermentation. The concept has little meaning in winemaking but is vitally important in brewing, where style and residual sweetness are indelibly linked. Brewers yeast strains dependably consume known persentages of sugar, a fact used to calculate when a fermentation is complete. A beer may finish at a specific gravity (s.g.) of 1.017, for example, and the only way to determine if that is truly the final s.g. is to calculate the apparent attenuation from the original s.g. and compare that with the expected attenuation of the yeast strain. Winemakers typically want yeast that will ferment to dryness, or attenuate 100%.

Antioxidant
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.

Amylase
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.

Anthocyanins
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.

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

Ameliorate
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.

Alcohol
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.

Albumin / Albumen
A water soluble animal protein found in egg whites and used as a fining agent. Albumin is colloidal, with a positive charge, that attracts negative charged tannins while removing fewer phenols and fruit character than gelatin. Not appropriate for white wines, but may remove some color from reds.

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.

Aftertaste
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.

Aging
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.

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. See Yeast Starter.

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.

Acidulous
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.

Acidity
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 principal 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.

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

Acetobacter
The principal bacteria genus, consisting of many species, responsible for converting alcohol into acetic acid -- vinegar -- in the presence of oxygen. Better know species include A. aceti, A. cerevisiae, A. cibinongensis, A. estunensis, A. indonesiensis, A. lovaniensis, A. malorum, A. nitrogenifigens, A. oeni, A. orientalis, A. orleanensis, A. pasteurianis, A. peroxydans, A. pomorum, A. syzygii, A. tropicalis, and A. xylinus.

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.

Acetic
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.

Acetification
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.

Acetaldehyde
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.