Glossary of Wine Terms

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Glossary of Wine Terms

acidity is what gives wine, and most other drinks, its tang. Lemons have lots of it; potatoes very little. A wine's acidity comes from the acids (mainly malic and tartaric) in grape juice. which diminish as grapes ripen. A hot summer may reduce acids to such an extent that some have to be added, a process known as acidification.

acids - group of chemical compounds which give grape juice and wine its tang and ability to refresh. Most common acids in grape juice are tartaric and malic.

American hybrid - variety bred from American and European vines.

ampelography - science of identifying grape varieties by detailed description of the appearance of the vine, especially its leaves

alcohol is the potent mood-changer that differentiates wine from grape juice. A wine's alcoholic strength is its concentration of alcohol.

analysis, operation to which almost all modern wine subjected which measures its vital statistics - alcoholic strength, total acidity, residual sugar - and usually much more besides.

anthocyans, phenolics which most strongly influence a red wine's colour, which is directly affected by its pH.

ascorbic acid, or Vitamin C, is often added to must during winemaking since it prevents oxidation, usually together with sulphur dioxide to keep white wines fresh.

barrel, the winemaker's most fashionable tool. barrel ageing or barrel maturation -keeping a wine in cask between fermentation and bottling so that it stabilises naturally in the presence of small amounts of air and also absorbs some flavour and possibly tannins from the wood, depending on its age and size, and duration of barrel ageing. barrel fermentation - fermentation in small barrels rather than a large tank, common for top quality white wine

bâtonnage, French for lees stirring.

Baumé, measure of sugar concentration in grape juice (and therefore grape ripeness) or must common in Australia.

botrytis, fungus affecting grapes benevolently (as in the 'noble rot' responsible for great sweet wines) or simply spoiling them with mould, depending on conditions.

Brettanomyces, wine fault so fashionable in the US that it is sometimes just called Brett. Wines affected by this spoilage yeast smell offputtingly mousey.

Brix, measure of sugar concentration in grape juice (and therefore grape ripeness) or must common in the US.

canopy - the above-ground parts of the vine, especially its leaves

canopy management - viticultural techniques designed to manipulate the canopy to achieve a specific end, usually optimising the quantity of grapes and quality of wine

cap - thick cake of grape skins floating on top of a vat of fermenting red wine.

carbon dioxide is the harmless gas given off during fermentation and that responsible for the bubbles in all fizzy drinks, including sparkling and slightly gassy wine.

carbonic maceration, special way of making fruity, early-maturing red wines, most notably Beaujolais, by fermenting them in a sealed vat filled with carbon dioxide.

chaptalization, common cool climate winemaking procedure which compensates for underripe grapes by adding sugar to the fermentation vat in order to produce a more alcoholic wine. Named after French statesman Jean Antoine Chaptal and usually strictly controlled.

classed growth, classified growth, Anglicisation of cru classé. term used in Bordeaux for the 60 or so wine estates, or crus, that were included in the 1855 classification of top MÈdoc and Graves properties. They were ranked, as in football divisions, into first (premier), second (deuxième), third (troisième), fourth (quatrième) and fifth (cinqième) growths. There are only five first growths: Chx Lafite, Latour, Mouton, Margaux and Haut-Brion.

clarification, umbrella term for a host of processes designed to ensure wine is crystal clear, including fining, filtration and refrigeration.

clone - an example of a variety replicated from a particular mother vine specially selected for a particular attribute(s).

concentration, new technique for concentrating flavour (and acid and tannin) in less ripe vintages.

coulure - deficient fruit set which may substantially reduce the size of that year's crop. Just after flowering, an excessive proportion of the nascent berries fall off, often because of unsettled cold, wet weather. Some varieties are more prone than others.

cultivar - South African term for vine or grape variety

crossing - variety bred from members of the same species

cru classé, French for classed growth

downy mildew - fungal vine disease.

élevage, French term with no direct English equivalent for the wine-maturing processes involved between fermentation and bottling.

enology, US spelling of oenology.

ethyl alcohol, or ethanol, is the sort of alcohol found in alcoholic drinks such as wine.

fanleaf - virus vine disease.

fermentation - the process whereby sweet grape juice is transformed into alcoholic wine, thanks to the action of yeast

field grafting - grafting a new variety on to an established rootstock in the vineyard. Increasingly common.

filtration, controversial clarification process of pumping wine through various different sorts of filter to remove suspended solids. It may also strip out flavour if overdone.

fining, clarification technique involving adding a fining agent (such as egg whites or bentonite) which attracts solids to fall to the bottom of a container.

flavour compounds, complex, still under-explored maze of phenolics responsible for the flavours of different wines.

foxy - distinctive taste of the grapes and wine of some American vines, especially Vitis labrusca and some of its hybrids. Methyl anthranilate is the (often) offending compound.

free-run is the name given to the juice or wine which flows without pressing.

French hybrid - vine variety bred from American and European parents

fruit set - early summer phenomenon which immediately follows flowering. As soon as the vine flowers, a proportion of them are fertilized, or 'set', to become berries, and eventually grapes. The higher the proportion, the bigger the crop is likely to be.

grafting - broadly, inserting a section of one plant into another so that they unite and grow as one plant. In a viticultural context, usually grafting a European fruiting vine on to a rootstock, often chosen for its resistance to phylloxera .

ha - hectare, or 2.47 acres

hl - hectolitre, 100 litres, or 26.4 US gallons

hybrid - variety bred from members of different species

inert gas, one such as nitrogen which does not react with wine and can be useful filling the head space of a container to prevent oxidation.

leafroll - virus disease of the vine

lees are the solids left at the bottom of a fermentation vat after fermentation. Relatively neutral-tasting white wines are often deliberately given prolonged lees contact and even lees stirring to generate more flavour and make them more stable.

malic acid, the sharp, appley acid most notable in grapes from cool years.

malolactic fermentation (MLF or 'le malo'), increasingly common second fermentation in which harsh malic acid is converted to softer, lactic (milky) acid making the resulting wine is more supple.

mercaptans, wine fault popular with Australian tasters. A skunky smell results from yeast reacting with the lees. It can be cured by assiduous racking.

millerandage - abnormal fruit set in which bunches contain berries of very different sizes because of poor fertilisation, often because of unfavourable weather.

must, useful word for the pulpy mass at any stage between grape juice and wine.

must weight - measure of grape ripeness, or sugar concentration in grapes

noble rot - the benevolent form of botrytis

oak, the most common sort of wood used for barrels. Usually either soft, sweetish American oak or tauter, more savoury French oak.

Oechsle, measure of sugar concentration in grape juice (and therefore grape ripeness) or must common in Germany.

oenology is the science of winemaking, practised by a (usually qualified) oenologist.

oxidation, potentially serious calamity that can strike grapes, grape juice and wine if they are over-exposed to oxygen, making them go brown (like a cut apple) and taste flat. Wines suffering from oxidation, sometimes from a less-than-airtight stopper, are oxidized.

oxygen, both good and bad fairy in the winemaking process. A small amount of oxygen at the beginning of fermentation encourages the yeast and during barrel maturation deepens colour, smooths flavour and makes the wine more stable. But too much oxygen causes oxidation and may eventually turn the wine to vinegar.

pH. All but the most technically-minded should skip this explanation of one of the wine bore's buzz words. pH is a measure of the concentration of acidity in a liquid but higher readings mean lower acid. Water, for example, has a pH of 7 while most wines have a pH of between 3 and 4 with very acidic wines having a pH of less than 3. pH and colour are also closely related.

phenolics, varied group of compounds found mainly in skins, stems and seeds in the case of grapes. They include anthocyans, tannins and many flavour compounds. Precipitated, they form an important part of wine's sediment and play a considerable role in wine ageing. Red wines are much higher in phenolics than white, which is why red wine is better at protecting against heart disease.

phylloxera - fatal vine pest which chews vine roots. The only remedy is to replant on phylloxera-resistant rootstocks.

potential alcohol of a liquid is the acoholic strength it would reach if all the sugar were fermented into alcohol.

powdery mildew - fungal disease of the vine.

pressing, important winemaking operation involving literally pressing the juice (white wines) or astringent press wine out of the skins. The quality of the resulting juice depends on how hard the grapes are pressed (as explained on p 67).

protective winemaking involves protecting the grapes, juice, must and wine from oxygen, typically by using sealed containers, low temperatures, sulphur dioxide and sometimes ascorbic acid.

pruning - arguably the most important operation of the vineyard year in terms of wine quality. During winter the vine is cut back leaving a specific number of buds responsible for producing the next year's crop. Although many other factors come into play, low-yielding vines in general tend to produce more concentrated wine.

pulp - the fleshy part of the grape containing most of the water, sugars and acids in grape juice. Apart from red fleshed Teinturiers, the flesh of all grapes is the same dull grey, no matter what the colour of the grape's skin.

racking is the operation of transferring wine from one container (typically a barrel) to another, leaving behind the lees. It can usefully expose the wine to oxygen and avoid reduction.

residual sugar (RS), the amount of unfermented sugar left in a wine after fermentation is complete, usually measured in grams per litre (g/l) or per cent. A residual sugar level of less than 2 g/l (0.02 per cent) is imperceptible to most palates. Although acidity counterbalances residual sugar, most wines with 25 g/l (2.5 per cent) residual sugar taste distinctly sweet.

reducing conditions are those which favour reduction, or losing oxygen, the opposite of oxidation. In excess, where a (usually red) wine is starved of oxygen, they can result in off-putting mercaptan or sulphide smells. rootstock - plant specially selected to form the root system of a fruiting vine of another variety by grafting

seed - part of the grape containing tannins. Care is usually taken not to crush them.

skin - very important part of the grape which contains most flavour compounds, pigments, and tannins - all highly desirable, not to say essential, for red wines but a more debatable ingredient in the white winemaking process

skin contact, deliberate policy of trying to extract as many flavour compounds and/or anthocyans as possible from grape skins into juice (in the case of white wines) or wine (in the case of reds).

sorbic acid, additive widely used in the food and drink industries to stun yeasts and moulds. Sometimes used for inexpensive sweet wines, it smells of crushed geranium leaves, excessively to a small proportion of particularly sensitive humans.

soutirage, French for racking.

stabilization, umbrella term for all the winemaking operations designed to stop wines developing a fault in bottle such as a haze, cloud or fizz, no matter what the storage conditions. It is practised most brutally on everyday wines.

stem/stalk - woody attachment of grape to bunch, high in often harsh tannins. All or most are usually deliberately eliminated by a mechanical destemmer prior to fermentation.

sulfur, alternative spelling of sulphur.

sulphides, off smells reminiscent of bad eggs which can taint heavily reduced wine.

sulphur dioxide, the most common and most useful winemaking additive used since Roman times, used mainly as a preservative, disinfectant and to ward off oxidation. Its use has been declining as consumers have become less tolerant of the freshly-struck match smell associated with sulphur. Some asthmatics also react badly to high doses of sulphur, which has lead to some countries' requiring the legend 'contains sulfites/sulphites' on wine labels. A tiny but increasing proportion of wines are made using no sulphur at all but they tend to be more fragile than most. Sulphur reacts readily with many other wine ingredients to form bound sulphur; it is only free sulphur which can be detected, although sensitivities vary considerably between individuals.

sugar - carbohydrates accumulated in the grape pulp during the ripening process which are transformed into alcohol by fermentation. See also chaptalization.

sur lie, French for a wine treated to lees contact.

tannins - cheek-drying, astringent phenolic compounds similar to stewed tea in effect on the palate which are found mainly in red wine and are derived from grape seeds, skins, and stems. They can help preserve red wines while they mature in bottle. Tannin management is one of the red winemaker's most important jobs.

tartaric acid, the most common and distinctive wine acid which is a particularly good preservative. A lot of the acid is precipitated as crusty desposits called tartrates, usually seen as harmless white crystals in white wine, and dyed deep red in red wines.

topping up, cellar operation of filling barrels regularly to avoid oxidation.

training - shaping a vine into a specific shape, usually to effect some form of canopy management

triage, French word for sorting, typically grapes for health and quality in the vineyard or as they are brought in to the winery.

ullage is the head space between wine and the top of a container such as a barrel or bottle. If it is excessive it can cause oxidation.

vieilles vignes - French for 'old vines', which generally produce more concentrated wine than young ones.

vigour - a vine's natural tendency to sprout forth leaves.

vine density - important vineyard parameter, the number of vines planted per unit of area

vinifera - vine species of European origin, as almost all the well known wine producing varieties are.

vintage - can mean either the particular year in which the crop was harvested or the process of harvesting itself

Vitis - the vine genus.

whole bunch pressing and fermentation - as opposed to destemming before pressing or fermenting. These two techniques, common in Champagne and Burgundy respectively, physically help drainage, the stems acting as conduits.

yeast, micro-organisms of many types which can encourage all sorts of chemical changes, including fermentation. Traditional wine producers tend to rely on ambient, invisible yeasts whereas modernists prefer specially cultured yeasts chosen for their suitability for a particular fermentation.

yield - the amount of wine or grapes produced per unit area, usually measured either as ton/acre, tonnes/ha or, in much of Europe, hl/ha. Many factors such as pressing regime, grape variety, and style of wine affect the conversion of weight of grapes into volume of wine but 1 ton/acre is very approximately equivalent to 17.5 hl/ha.

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