WHAT IS WINEMAKING?
Winemaking is the craft and science of growing grapes and making wine. It is algo called vinification, which is the production of wine, starting with selection of the grapes and ending with bottling the finished wine. The science of wine and winemaking is known as oenology. A person who makes wine is traditionally called a winemaker or vintner.
Winemaking, can also be divided into two general categories: still wine production (without carbonation) and sparkling wine production (with carbonation - natural or injected).
It should be born in mind that there is no standard winemaking techniques procedures for all wines, all wineries, and all wine-producing countries and regions. Therefore, the following are basic explanations in which concepts have been quite simplified:
WHITE WINEMAKING
The basic difference between the vinification of white and red wines is that the first are obtained by fermenting the must from the grape-pressing, while rosés and red wines require prior maceration of the grapes to extract the pigment from the skin.
First of all, rapid transport of the grapes from the vineyard to the winery is essential. Samples are taken from all the trailers arriving at the winery for their analysis: acidity, pH and level of sugar. Additionally, other parameters related to the soundness or health of the grapes can be carried out. Once the results have been obtained, and if found satisfactory, authorisation is given to place the grapes in the hoppers. From there, the grapes move on to the destalkers or destemmers, where the berries are separated from the stalks or stems.
Quality white wines are obtained by gentle pressing to avoid damaging the plant components of the grape (stalks, seeds, etc.) and thus prevent the appearance of grassy notes and flavours.
Proper separation of the musts is essential (only the free-run juice and the first portion of the pressing should be used) to produce elegant and balanced white wines.
The juice has to be cleaned to eliminate finer solids and some of the cloudiness resulting from the pressing process. Normally, this can be done through debourbage or setting: an operation consisting of separating the solids from the juice by decantation, i.e.: resting the juice for a few hours at a low temperature and letting the solid particles settle down at the bottom of the deposit. There are also quicker filtering methods that carry out the same function (vacuum filters -RDV-, flotation, pectolytic enzymes, etc.).
Once the juice is cleaned, fermentation can begin. Yeasts (Saccharomices cerevisae) are usually added to the must to facilitate the process. This operation is a crucial part of the winemaking process. Basically, it consists of the following:
The yeasts transform the must sugars into alcohol. In addition, there is a release of carbon dioxide (CO2) and heat and at the same time aromatic compounds are produced. Fermentation is an exotermic process which produces heat. The temperature has to be controlled in order to avoid an excessive rise which would speed up the process and “burn” the aromas and could even end up stopping the fermentation. That is why fermentation most usually takes place in stainless steel fermentation tanks with temperature control: Refrigerating systems ensure that the fermentation of white wines takes place at a low temperature (16–19 °C) to guarantee the correct evolution of aromas.
Some white wines have a high content of malic acid (especially those from cooler regions). This acid is the one found in green apples, which is where its name comes from malus, (Latin for apple), and gives the wine grassy notes, making it advisable to transform it into the less aggressive lactic acid (present in yoghurt). The process is known as malolactic fermentation and is due to the action of the lactic bacteria contained in the wine. This is normally achieved naturally after the alcoholic fermentation, leaving the wine in contact with the lees.
The wine obtained has to go through a series of preparatory processes (stabilization stages) before being bottled to guarantee its brightness and stability and to ensure its characteristics are maintained until the moment of consumption: tartaric stabilization (normally through cooling), filtration, bottling.
There are several variations to this basic process:
- Vinification with cold maceration: After crushing the must is not immediately separated from the skins. It stays “macerating” in a vat for a few hours at a low temperature. The purpose is to allow the precursors of aromas to pass into the must, but not the unwanted substances.
- Cask-fermentation: After pressing, the juice is placed directly inside the oak barrels. A slow fermentation takes place (small quantities of juice resulting in low fermentation temperatures. At the end of the fermentation the wine left in contact with the sediment is periodically remixed with the liquid part in a procedure known as “lees stirring” or batonage. The oxygenization resulting from the porosity of the wood prevents the wine in contact with the lees from developing unpleasant odours.
RED WINEMAKING
Red wines are distinguished from whites because of their colour, astringency and a certain bitterness. These characteristics are due to the presence of polyphenols: anthocyanins (red-purple) and tannins (yellow-brown and astringent, bitter taste).
These components are found in the skin (colour, astringency and bitterness) and also in the pips (astringency and bitterness). During the grapes’ ripening process, these components are gradually formed and it is during the fermentation-maceration process when they are extracted.
When the grapes are received at the winery they are usually subjected to various tests. They are then destemmed and crushed, a process that breaks the skins in order to facilitate maceration, followed (or prior to) by destalking / destemming, which consists of separating the grapes and the stalks, as these can contribute astringent, vegetal and grassy flavours as well as a significant amount of water. Only under exceptional circumstances are the stalks/stems left during vinification.
When describing winemaking processes, the distinction between pressing and crushing must be clear: During crushing, the grape is broken with a rather delicate mechanical action and a large quantity of the must is extracted. The grapes are then transformed into liquid with suspended solids. Pressing extracts all the juice from the grapes.
This paste is then vatted, i.e., put into vats or tanks (These can be made of stainless steel, concrete, fibreglass or even wood) so that alcoholic fermentation and maceration can take place. Maceration is the contact and remixing of the liquid part of the most with the solid parts – skins, pips and, in some cases, the stems- which exude important components into the must: colour (anthocyans), tannins and aromatic precursors. During fermentation, the CO2 produced pushes solid matter (basically skins and pips) to the top of the tank, forming a compact floating layer which is called the cap. The liquid portion needs to come into contact frequently with the cap to enable the solid particles to transfer material to the must-wine. There are several stirring techniques: mainly pumping over, pigeage or mashing-down, délestage…
In modern cellars fermentation is strictly monitored: Selected yeasts are often used instead of the “native” ones and the temperature is kept below critical levels using cooling systems and heat exchangers fitted on the vats. We can even use sensors inside the vats in order to monitor the fermentation parameters (temperature, acquired alcohol, etc).
Maceration lasts for as long as the œnologist finds it appropriate, depending on the state of the harvested grapes, the vinification style, the grape variety used and the type of wine we wish to make… Colour begins to drop while polyphenol content continues to increase (astringent sensations) and at this point devatting is advisable. De-vatting consists of separating the wine from the solid parts or pomace, which is pressed to yield various qualities. The free-run wine is obtained through gravity. The weight of the pomace causes a certain amount of wine to be percolated against the draining holes of the press: this liquid is known as press wine. The cap (pomace) is then pressed again several times. The quality of this press wine decreases as the pressure increases with the number of pressing cycles.
After devatting, malolactic fermentation (carried out by lactic bacteria) takes place. For ageing wines, the period in oak barrels usually begins straight after malolactic fermentation but sometimes wines are put into barriques as soon as alcoholic fermentation is over, when they are still cloudy, and malolactic fermentation takes place in wood.
During the entire process several rackings take place. This means that the wines are transferred from one tank into another in order to leave solid parts or residues behind. The wines made of different varieties and even from different vintages are blended in the process known as coupage. Before bottling the wines or putting them in oak casks, a final fining process takes place: stabilization. Traditionally, the cold winter temperatures used to provoke the settling of potassium bitartrate crystals naturally. Nowadays, this is usually supported by cooling systems.
MATURATION
It is a generally-accepted that, in order to achieve a higher quality, certain wines need to undergo a certain time in wood, which is then complemented by a stay in the bottle. This is the process known as ageing. Most of the worlds great wines have been thus aged.
The most widely-used container for this is the oak barrel, with an approximate volume of 225 litres.
Other words related to coopery:
- Toasting: Tostado
- Seasoning/Curing: Curado
- Shaping: Domado- Splitting: Hendido
- Sawing: Aserrado
According to the Webster dictionary, the terms “cask”, “barrique” and “barrel” are synonyms. However, for certain winemakers, the word “cask” refers to a larger container and the word “barrique” would be a 225-litre cask.
Factors that are usually taken into account when selecting new barrels are the source of the oak, the way it has been cut (splitting or sawing) and how it has been toasted. The standard small cask is the barrique, which contains 225 litres, equivalent to 300 bottles. It has now been adopted by wineries in most parts of the world.
Normally a cask-aged red wine will spend a maximum of eighteen months to two years in cask before bottling. During this time, the casks will be topped up (ouillage) regularly and racked every six months or so. Before the final racking, the wine will be fined, to settle any suspension present.
Finally, the wine has to be left to age in a reducing atmosphere, that is, in the absence of oxygen, in the bottle. During its stay in the bottle, the wine acquires increased aromas and the tannins from the wood become more polished by combining with the wine’s anthocyanins.
To preserve a wine in a reducing environment, we need the invaluable help of the cork stopper. The amount of oxygen that normally enters properly-closed bottles lying on their sides is minimal, not to say non-existent. This is because the humid cork adheres perfectly to the bottle neck’s walls. During the first months, a small portion of oxygen, present in the cork, may be contributed to the wine. Since the cork consists of empty cells, it slowly releases the air contained in these as it is compressed by the bottleneck. After this, the amount of yearly oxygen intake in the bottle is negligible. However, when the cork material is defective or the stopper has been damaged in the bottling line, air may be let into the bottle, oxidising the wine it contains.
Effects of bottle ageing:
- Global refinement
- Enrichment, gain of aromas
- Polishing of tannins
SPARKLING WINES
Sparkling wines are made following different methods in different wine-growing regions. The most common method is the “Champanoise”, “Classical” or “Traditional method”.Any of these names describes the most traditionally-known method of making sparkling wine, and the only method accepted for making certain quality sparkling wines (e.g. cava, champagne, etc.). By means of this system, a natural sparkling wine is achieved whose production and ageing process take place integrally in the same bottle. The steps that make up the process are the following:
- The wine will be made with selected grapes from the varieties and growing areas stipulated by the Regulatory Council of the region.
- The grape harvest, which is always early in the season compared to the picking for still wines. In that way, the alcohol level is kept low, since secondary fermentation will boost it later.
- The grapes are pressed immediately, by-passing the crushing equipment, to avoid both oxidation and colour in the wine.
- A young, acid, still base wine is obtained from the first fermentation at controlled temperature, usually in stainless steel tanks. It may then be blended with wines of other varieties (coupage or blend) or stocks of older wine saved from previous vintages, to keep a consistent “house” style, or cuvée.
- The wine is bottled with the addition of the so-called “liqueur de tirage”, which consists of yeasts and sugar dissolved in wine, with the aim of producing a secondary fermentation in the bottle.
- The bottles are sealed with a stopper and a cork-lined metal crown cap or tirage cork and laid to rest on their sides. The second fermentation starts: the process creates three things: alcohol, CO2 gas and, when they die, a sediment on the side of the bottle. As the wine slowly ferments, the gas, being unable to escape, dissolves into the wine.
- The sediment has to be removed from the bottle. In order to do so, it first has to be collected in the neck of the bottle. That is a long process know as remouage. Traditionally, the bottles are placed at a forty-five degree angle, necks-down, in “A-shaped” racks, called pupitres. The bottoms of the bottles are grabbed, giving the bottle a small shake, an abrupt back and forth twist, and a slight increase in tilt, letting it drop back in the rack. This action is called riddling and nowadays it is a fully automated process in many wineries.
- Disgorging: Removal of the provisional crown cap or tirage cork and removal of the sediment by freezing the neck of the bottle.
- Finally, the expedition liqueur is added, consisting primarily of wine and sugars in varying proportions, and the definitive cork is inserted.
VOCABULARY FOR WINEMAKING
- Alcoholic fermentation (Fermentación alcohólica): The conversion by yeast of sugar into alcohol compounds. It is the fundamental and biological process by which grape juice is converted into wine. It originates from the metabolic activity of some yeasts and bacteria which have the property of basically transforming carbohydrates (the vast majority sugars) under anaerobic conditions (absence of oxygen, in an enzymatic process known as glycolysis) into alcohol and carbon dioxide.
Fermentation can take place in stainless steel tanks, in large open wooden vats, in a "lagar", inside a barrel or even in bottle, as in sparkling wines.
Despite Louis Pasteur having concluded in his studies that "fermentation is life without oxygen", today it is widespread knowledge that this is not entirely true: only under extreme conditions. Yeasts have the rare ability of being able to survive both aerobically and anaerobically.
Before getting to the oxygen-lacking stage and under certain temperature constraints, yeasts can start fermentation by consuming oxygen in large quantities, as much from the atmosphere as diluted in the must. In aerobiosis, growth of yeasts is very rapid (primary fermentation) and only four grams of sugars are required to generate one gram of yeasts. As oxygen becomes scarce, yeasts result to glycolysis to obtain energy, with alcohol and C02 being generated as by-products. Under these anaerobic conditions (secondary fermentation) biomass formation is highly restricted, which leads to more than hundred grams of sugars needed to create just 1 of yeasts.
Production of alcohol, and the prolonged lack of oxygen and sugars, eventually cause the death of yeasts (turning into lees), which will occur depending on the dominant strain or strains and their specificities with regards to tolerance and alcohol generation levels.
- Barrel fermentation (Fermentación en barrica): Quality winemaking procedure consisting of fermenting the must in oak casks. It is very costly and aggressive with the barrel, but contributes to the formation of tertiary aromas and adds complexity to the wines. It is far more used for whites rather than reds, given the difficulty of drawing off and removing the skins in a vessel with such a tight opening. The technique seeks to extract important flavour and aromatic compounds from the wood by stirring the lees, without having to take especial care in controlling temperature.
- Bottle fermentation (Fermentación en botella): Important quality factor in the production of sparkling wine by the champenoise method, though highly undesirable if it occurs in still wines. It can come about if there are remains of residual sugar and/or malic acid, along with yeasts and lactic bacteria. Under certain temperature conditions and depending on levels of alcohol and sulphur dioxide, refermentations (alcoholic or malolactic) may take place giving birth to carbon dioxide detachment, formation of clouds and/or unpleasant aromas.
- Must (Mosto): Unfermented grape juice, including pips (seeds), skins and stalks.
It is the intermediate liquid between un fermented grape juice and wine, which results from mechanical crushing of grapes or by their breakage by means of exerting pressure (pressing). As a consequence of these operations it is a mixture or paste made up of juice, stalks, skins, seeds and pulp, which may already have some alcohol content.
Legally, it is any fermented or partially fermented grape juice which does not attain the alcoholic strength set to be considered a wine. Solids found within it will eventually make up the pomace when they are removed.
Depending on their composition, extraction techniques employed and time of contact, they will define the wine’s type, style and character. The first clean must collected through draining (whites, most rosés) or bleeding (reds) is called drainings or free-run must or juice, which either flows after natural breakage of the grapes owing to the weight of others or by crushing, very slight pressing or drawing off. It usually makes up about 70% of total available juice and is much lower in tannins than heavily pressed musts, called press must or wine. The latter will vary in composition and quality as a result of a 1st, 2nd or 3rd pressing, with astringency and bitterness growing exponentially.
- Carbonic maceration, intracellular or intact berry fermentation (Maceración carbónica, fermentación intracelular o de uva entera): It as much describes a process for making young red or rosé wines (not so for whites, since it has not proved to deliver good results), as does the fresh and fruity wine type made as a result of the said process.
The latter is defined as the transformation of sugar in small quantities of ethanol inside the pulp of the intact grape, caused by its own enzymes and favoured by man. This occurs in the absence of yeasts and oxygen (anoxia), and under specific temperature conditions.
It is carried out by placing whole bunches in tanks in an anaerobic environment (for which they are filled up with carbon dioxide) and at relatively high temperatures, for one to three weeks.
The uncrushed berries generate alcohol within them (not beyond 2.5° of the total alcohol content by volume in the final wine), as well as important aromatic and flavour compounds. Moreover, they multiply their glycerol content, increase their pH and lose a great proportion of malic acid.
The weight of the grapes themselves (they rest on each other), the increase in intracellular pressure and the rising temperature, eventually make the grapes explode, triggering the habitual maceration and alcoholic fermentation (by action of yeasts) in the presence of skins, seeds and stems.
The changes produced at the interior of the grape result in a final wine with accentuated colour and brightness, potent and fruit aromas (associated above all to the formation of intracellular volatile esters and aldehydes, such as ethyl cinnamate or benzaldehyde), and which is less tannic than those manufactured through the usual procedure of crushing, destemming and pressing.
Carbonic maceration wines are normally not apt for barrel ageing and should be consumed early.
- Cold soak or maceration (Maceración en frío): A technique for extraction of polyphenols (especially aromatic) consisting in cooling and holding the must at a temperature of about 10°C (50°F) for several days, with a generous dosage of sulphur dioxide and under anaerobic conditions, before alcoholic fermentation is triggered.
It is performed in the belief that absence of alcohol and oxygen, along with presence of sulphur, allows for better extraction of complex flavours and aromas. As it is performed in cool temperatures, extraction of anthocyans (pigments responsible for wine colour in red and rosé wines) is quite limited at this stage. This is so because each phenolic compound has its own rate of extraction depending on temperature and substrate composition.
- Acidity (Acidez): The quality of wine that gives it its crispiness and vitality. A proper balance of acidity must be struck with the other elements of a wine, or else the wine may be said to be too sharp, having disproportionately high levels of acidity (or too flat) having disproportionately low levels of acidity.
It is the measurement of all acids present in wine or of its acid intensity. The three main acids found in wine are tartaric acid, malic acid and lactic acid. The first two come from the grapes and the third from Malolactic fermentation which often occurs in the winemaking process.
- In the first case, acidity (or total or titratable acidity) is divided into fixed acidity and volatile acidity, and is commonly measured in grams of tartaric acid per litre.
- In the second case, the pH logarithmic scale is employed, which runs from 1 (maximum level of acidity) to 14 (maximum level of alkalinity), by using reactive substances such as lye.
Most wines contain between 4.5 and 7.0 gr./l. of tartaric, which correspond to values of pH within 3.2 and 3.7. Winemaking regulations normally dictate norms for compulsory minimal acidity levels.
Among many other characteristics it can be noted that acidity is a natural wine preservative and helps maintain its colour and aromatic features. Hence, in the right measure, it is an essential constituent of wines which will determine their life span, particularly of those being aged in wooden vessels or bottles.
- pH: A measure of the acidity. The lower the pH, the higher the acidity. The term comes from the French Pouvoir Hydrogéne meaning "hydrogen power". pH is a shorthand for its mathematical approximation: in chemistry a small p is used in place of writing log10 and the H here represents [H+], the concentration of hydrogen ions.
- Destemmer (Despalilladora): The machine used for destemming, and working on the principle of sieving. It normally consists of a perforated rotating cylinder in which the liquid mass is introduced after crushing (operation that may be performed in the seme device, which would be then known as a crusher-destemmer). The must and the smaller particles (e.g. skins) flow through the orificies, wilst larger portions of stalks remain within and are subsequently removed for pressin (pomace).
- Stalks, stems, or cap stems (Raspón o escobajo): Parts of the vine, particularly small green sprouts and shoots stems, which keep bunches and their grapes attached to the plant (though they may also include larger, shoots, leaves, etc.). They are very rich in green tannins, acids and lingenous matter which lend astringency and bitterness to wines. Stalks tend to be eliminated by destemming.
- Pressing (Prensado): Operation by which pressure is exerted by means of a press onto grapes, bunches, pomace or remains of the cap to either extract juice, must or wine from them. The exact time of pressing and its intensity are quite variable, and depend of the wine type or style sought. In mos white and rosé wines, a slight pressing is carried out before fermentation, after crushing and desteming of the grapes (by which the free-run must is obtained through draining). It may even be performed onto whole bunches either when the grapes exhibit great ripeness, or when making wines by freeze concentration or ice wines. With regard to red wines, pressing is usually much more intense and is accomplished onto the paste or skins, either during alcoholic fermentation (e.g. carbonic maceration wines) or once the latter is overs.
- Free run juice, draining or dejuicing (Escurrido): Juice obtained from grapes that have not been pressed.
In white winemaking, the operation consisting of collecting the first clear must that runs off the crusher or the press either before pressing starts or by exerting a slight pressure. This must is called drainings or free-run must or juice, which is normally introduced in special tanks to be vinified apart.
In red wines (and when making some rosés), the must mixed with its solids (chiefly skins) is obtained by crushing the grapes (which may be destemmed or not). The mixture will be subsequently introduced in tanks for fermentation, during which the skins will float making up the cap. If clear and coloured must (free-run must) is drained or removed during fermentation (or free-run wine, once the latter is over), draining would be equivalent to bleeding and/or drawing off of rosé and red wines.
- Clarification (Clarificación): A winemaking process involving the fining and filtration of wine to remove suspended solids and reduce turbidity.
The set of winemaking operations whose objective is the removal of suspended particles froms musts or wines, so as to make them more stable and cleaner. The nature of the insoluble solids is quite diverse and includes fragments of mud and leaves (dregs), skins, stalks, seeds, pulp, colloids, tartrates, pectins, remains of yeast (lees) and bacteria, gums; and even proteins, polyphenols (oenological tannins) or aminoacids.
Somo of the most important clarification procedures are settling, drawing off, flotation, fining, filtration, centrifugation and racking.
Finally, the techniques employed in stabilization can also be considered as itended for clarification or vice versa. These procedures should progressively be less aggressive the more the quality level sought, for many of the above-mentioned particles significantly contribute to the character and organoleptic properties of the wines.
- Clean, clearness or limpidity (Limpio o limpidez): The cuality of a wine exhibiting clearness to the eye. It may also refer to the perception of the wine on the nose. In the latter case, it would designate the one which is honest, with few but marked aromas, and free of unplesant off-scents. "A clean wine to the eye". A wine which is clean on the nose.
The assessment of how clean a wine is, whereby the degree in which it is free from clouds, haze or sediment is judged. Whilst a cloudy wine is generally defective, this is not always the case in those which throw sediment, for this may be a sign of a light filtration and quality (e.g. Ports or sturdy reds). "A wine showing immaculate clearness".
- Hazy, cloudy, or foggy (Turbio, anubado, o velado): A wine having clouds, wich affect ists clearness, but which does not necessarily dimninish its quality on the nose or mouth/mouthfeel (and for this reason, distinct from dirty).
- Settling or débourbage (Desfangado, deburbado o sedimentación): Name of the clarification process by which the must or wine is held in a container, normally a tank, so that solid matter falls to the bottom for their removal.
- For the production of white and most rosé wines, it is carried out before fermentation begins, after crushing and pressing of the grapes, and/or after skin contact.
- As for reds (and some rosé wines), skins and some solids (the cap) are left in the wines during fermentation and maceration which will be romoved by drawing off. Therefore, settling will take place once the fermentation is over.
Depending on the type of wine and the style of the winery, it will be performed with more or less intensity. By and large, high quality wines suffer from lighter settling. It is implemented at low temperatures, which facilitates larter particles as are earthen ones, dust, seeds or stalks to rapidly react to the slightest movement becoming suspended again. In this case, encouraging substances for precipitation may be employed such as pectinase enzymes or bentonite.
- Filtration (Filtración o filtrado): The removal of unwanted particles suspended in wine or grape juice. It is one of the most widely employed winemaking techniques to accelerate clarification and stabilization of wines, consisting of the elimination of suspended solids by making the wine run through a filter.
It is usually performed in stages depending on the production phase and the type of filtration. There are basically two kinds, which go from lesser to greater capacity: layer or depth filtrations, usually less aggressive for larger particles (by means of diatomaceous earth, cellulose, press filters, etc.), and membrane filtrations, for micro particles (employing kieselgurs and perlites, by cartridges, millipore, etc.).
The former are carried out after fermentation or racking operations, while the latter tend to sterilize wines before bottling. In quality wines, it is commonly accepted that aggressive filtrations eliminate relevant solid compounds which contribute to their complexity, as well as tannins and colouring matter which aid them to age. An unfiltered wine can throw much sediment and tartrates.
- Flotation (Flotación): An operation for clarification of the must, which consist of pumping air from the base of the tank so that the fine bubbles react, oxidise and lift the polyphenols, polymers and other insoluble substances to the top, so they can be removes.
- Pectic enzyme (Enzima pectolitica): An enzyme added to fruit to increase juice yield. Also used as a clarifying agent in fruit wines when added to wine or must to eliminate pectin hazes.
- Pectins (Pectinas): Acidic and neutral polymers produced by vines to stick cells together in their tissues, as well as to regulate their ionic balance and pH. They are incorporated into the wines during the winemaking process.
These compounds, which contribute to the formation of colloids, are quite diverse in nature and are formed by galacturonic acid molecules combining with carbohydrates that frequently build calcium bonds. They give rise to polysaccharides or gums such as arabinose, galactose and mannose and may be degraded by enzymatic reactions of yeasts, giving off methanol.
Their precipitation and elimination by clarification and stabilization procedures is achieved through usage of pectinase enzymes.
- Yeasts (Levaduras): A microscopic unicellular fungi responsible for the conversion of sugars in must to alcohol. This process is known as alcoholic fermentation.
Single-cell fungi which are abundantly found in nature and display very different forms. They pertain to the kingdom of Fungi, inside which they are grouped within the true fungi or the Eumycota division.
In oenology, the most important are those pertaining to the family Saccharomycetaceae, which contains some 20 species of the genus Saccharomyces (from the Greek sakcahr "sugar" and mykes "fungus") and are responsible for the transformation of must into wine, such as Saccharomyces cerevisiae (or S. ellipsoideus), Saccharomyces bayanus, Saccharomyces uvarum or Torulaspora delbrueckii.
There are a myriad of synonyms, strains and variants of each one of them, though the first one, S. cerevisiae, whose common name is baker’s yeast, stands out among the rest which bear appealing second names such as carlsbergensis, sake, chevalieri, beticus, oxydans, etc.
They are of the utmost importance in vinification since they are responsible for fermenting most of the sugars contained in the must, besides being very resistant to high concentrations of alcohol and sulphur dioxide. Most of the yeasts which do not belong to Saccharomyces are harmful for winemaking (e.g. Kloeckera, Pichia or Candida) with a few exceptions in other genera and subdivisions.
All of these species, plus other genera of yeasts and various microbes, may coexist during fermentation. The art of winemaking may then be defined as the art of controlling the dominant strain which has been chosen to ferment, whilst the rest remains dormant or is eliminated. In this respect, temperature control, S02 usage and the oenological properties inherent to the yeasts and their enzymes (especially during autolysis) prove to be essential.
Yeasts can naturally be present in the must (native yeasts) airborne or adhered to the skins (on the bloom), or artificially inoculated by man (selected yeasts).
- Carbon dioxide CO2 or Carbonic gas (Dioxido de carbono CO2 o Carbónico): A natural by product of the fermentation process in which yeast cells convert sugar into nearly equal parts alcohol and carbonic gas.
While a small amount stays presence in the wine as carbonic acid, most of the gas will rise to the surface of the fermentation vessel and attempt to escape into the air. If the fermentation vessel is closed (such as a sealed wine bottle used to make sparkling wine), the gas will dissolve into the wine and when released will make the wine sparkling.
It is the chemical name by which the gas formulated as C02 is known, which is naturally present in the atmosphere and essential for life. The vine’s growth is also dependent upon it. The plant fixes it on its leaves where its is combined with water by photosynthesis thus creating sugars, the precursors of acids and compounds which lend flavour/taste, aroma and colour to wines.
It is given off in substantial amounts during the wine’s fermentation through the metabolic action of yeasts and is responsible for the effervescence of sparkling and perlant/pétillant wines. In a primary stage of fermentation, in which oxygen is abundant, yeasts metabolize sugars and starch producing water and C02. As carbon dioxide increases, oxygen decreases and alcohol is formed.
The continued emission of the gas displaces oxygen and at concentrations above 50,000 ppm (5% by volume), it becomes toxic. One or two percentage points more and the gas becomes lethal. Therefore, the utmost care should be taken to prevent people getting near fermenting wines. If strictly necessary, employees should wear oxygen masks, for C02 is odourless.
In general, when still wines are made, the quantity of C02 which remains in them is minimal, though perceptible in the mouth in some young red and white wines after uncorking. In contrast, in certain young wines, especially whites, C02 may be encouraged to remain in the bottle so as to enhance freshness and vivacity. As regards sparkling wines, its presence is of the essence and is normally achieved after inducing a second bottle fermentation. In solid form, C02 is known as dry ice, and may be used during carbonic maceration or cold soak to provoke anaerobic conditions.
- Temperature (Temperatura): A critical factor for wine in all its aspects. It affects vine culture, winemaking, tasting and wine commerce.
In oenology, temperature is the key to the occurrence of important biochemical changes during fermentation because it has a profound impact on the growth and activity of yeasts and bacteria.
There is also a correlation with non-enzymatic chemical reactions which determine the wine´s life expectancy (i.e. oxidation). In general, the higher the temperature (within a band) the more biological and chemical processes affecting wines speed up, whereas the lower it gets, the quicker they are decelerated or even halted to a complete stop.
Controlling temperature is therefore essential in winemaking and the mechanisms and methods devoted to it are increasingly more abundant. As for the biological activity during alcoholic fermentation, the growth and development of the microscopic organisms responsible for making wines is altered and even totally inhibited at temperatures under 10ºC (50ºC). As the thermometer rises (up to 25ºC-30ºC), the effects and reactions accelerate. From this threshold upwards, the slowdown begins (with possible formation of undesirable compounds and even causing stuck fermentations), which como to a halt in the 40ºC-45ºc range (104ºC-113ºC) when the majority of microorganisms die.
During fermentation, each band has a significant effects in all wine types. Whites habitually ferment at lower temperatures to avoid excesive extraction of oxidative and astringent compunds, whilst they may be higher when producing red wines for exactly the opposite reason (tannins and colour are extracted).
Temperature is of such importance that all winemaking processes are influenced by it (e.g. malolactic fermentation, carbonic maceration, ageing, formation of aromatic compunds, colour, etc.). Therefore in each process and at every stage, it should be controlled to assure the wine´s desired quality.
- Malic acid (Ácido málico): A strong tasting acid in wine reminiscent of the flavor of green apples. The amount of malic acid in grapes is gradually reduced during the ripening process while the grapes are on the vine and can be further reduced during winemaking by fermentation and malolactic fermentation.
It is a very unstable organic acid of fruit origin, which has a very sharp and bitter flavour / taste and is formed inside the berry in large quantities at veraison. It participates in multiple chemical reactions during the ripening of the grapes, declining fast in the processes (Krebs cycle).
Depending on the time of grape harvest, grape variety and temperature variations; it can get into the wine at different concentration levels to which it confers freshness, vivacity and green apple tones. In any case, it is not convenient for it to exceed the threshold of 2 gr/l. Once in wine, it is easily transformed by lactic bacteria into the softer lactic acid.
- Malolactic fermentation (Fermentación málolactica): Also known as malo or MLF, a secondary fermentation in wines by lactic acid bacteria during which tart tasting malic acid is converted to softer tasting lactic acid, during which carbon dioxide is generated.
It is a natural occurring phenomenon by which the sharp and unstable malic acid (typical of apples) in wine is converted, through intervention of lactic bacteria, to the mellower lactic acid (commonly found in milk). The resulting wine will become more stable and softer, though its completion is averted in some young and many base wines for the production of quality sparklers to keep them fresher and preserve primary aromas.
It takes place spontaneously (totally or partially), in all wine types in which lactic bacteria are present and under certain constraints. It is much more common, and comes about quicker, in red wines than in whites or rosés.
MLF is always accompanied by microbial occurrences such as bacterial growth and physical/chemical reactions associated to all fermentation processes such as clouds, formation of new compounds, C02 detachment and wine colour variations, which affect its backbone and organoleptic properties.
Among the array of characteristics bestowed by MLF onto wines, the most important one is that of deacidification since malic acid has a much lower pH than lactic. It may occur in the must, when bacterial growth anticipates that of yeasts, during alcoholic fermentation, normally at its later stages or when it has already stopped, or when the wine is in tanks, barrel or even in bottle.
Several factors influence its conclusion and control, the most significant being pH (it takes place in the range of values between 3 and 4), temperature, levels of sulphur dioxide, alcoholic strength and nutrient availability (e.g. lees).
- Lactic bacteria (Bacterias lácticas): Group of bacteria whose main characteristic is the production of lactic acid and carbon dioxide from malic acid, in a process known as malolactic fermentation.
They are divided into three genera: Oenococcus, Lactobacillus and Pediococcus. These bacteria are frequently found in old wooden barrels, though it is customary to use laboratory cultivated strains to provoke fermentation.
Bacterial growth should be thoroughly controlled so they do not cause clouds, strange odours or an anomalous generation of amines. The controlling parameters of bacterial growth are the absence of micronutrients (residual sugar, contact with lees, etc.), temperature (the lower it gets, the lesser the activity); acidity, alcoholic strenght and sulphur dioxide levels (the higher they are, the lesser the activity) and frequently racking.
- Lees (Lías): Wine sediment that occurs during and after fermentation, and consists of dead yeast, grape seeds, and other solids. Wine is separated from the lees by racking.
In general, a synonym for dregs or gross lees, bottoms or smaller and suspended parts of pomace. In particular, solid substances (with prevalence of dead yeasts) which precipitate in tanks and other vessels after the processes of clarification and stabilization.
If they are deliberately employed during winemaking they are stripped of the coarser and harder elements, leaving the finer parts (fine lees), from which aromatic compounds are obtained by extraction and stirring. In this case, a stringent control of autolysis should be exerted for unpleasant odours and/or mercaptans may be generated (they then become bottoms). The operation of removing fine lees is usually known as lees racking.
- Stabilization (Estabilización): The process of decreasing the volatility of a wine by removing particles that may cause unwanted chemical changes after the wine has been bottled. In winemaking wines are stabilized by fining, filtration, adding sulfur dioxide or techniques such as cold stabilization where tartrate chemicals are precipitated out.
Set of fundamental winemaking operations which principally aim at ensuring quality and stability of the wine before it reaches the market, as well as allowing it to develop correctly inside the packaging as it moves along the distribution chain and during laying down / storing. These operations complement and mingle with those of clarification, though more specifically intended to assure microbiological and physical-chemical stability (thus avoiding faults/casses).
Microbiological stability is achieved by averting the growth of undesirable yeasts and bacteria, which may lead to fermentation in bottle or to wines becoming pricked. For this reason, controls over levels of residual sugar, total acidity and aeration are essential. Careful employment of sterilization techniques (i.e. pasteurization) during filtration and bottling, as well as correct usage of sulphur dioxide or the adequate realization of malolactic fermentation (e.g. through controlled addition of lysozyme) would suffice in this case.
As for physical-chemical stabilization, there are many ways to achieve it. of which some of the most outstanding are cold stabilization and filtration, electrodialysis, use of metatartaric acid, oenological tannins, calcium tartrate, resins, mannoproteins (tartaric stabilization), selective fining for eliminating unwanted polymers as proteins and/or tannins, or corrective measures for ferric or copper-caused wine faults.
- Tartaric acid (Ácido tartárico): The primary acid found in wine that is detectable only on the palate. Prior to veraison, the ratio of tartaric and malic acid in grapes are equal but as malic acid is metabolized and used up by the grapevine, the ratio of tartaric sharply increases.
It is the most abundant organic acid of fruit origin found in grapes and one of the more stable, reasons as to why it plays a major role in the maturation of wine. Due to its prevalence, its concentration level is the usual measure to quantify fixed acidity. It adds vinous and ripe fruit notes with pleasant and fresh flavours to wines.
A most important aspect is that tartaric acid may precipitate spontaneously in salt form (potassium tartrate or calcium tartrate) as a consequence of the insolubility provoked by its interaction with alcohol at low temperatures, giving rise to the famous wine argols or crystals. Their presence in wines is increasingly accepted because it simply indicates fewer manipulations in the making process (e.g. less cold stabilization) and besides they carry many beneficial compounds for human health. Its usage is authorised and regulated for acidification, chiefly applied under its levo-form (L-tartaric).
- Tartrates (Bitartratos): Crystalline deposits of the tartaric acids that precipitate out of the wine over time or through exposure to cold temperatures such as the process of cold stabilization.
It is also known as wine argols. Generic term applied to the crystalline deposits that spontaneously precipitate during fermentation or ageing of wines. This is a consequence of the insolubility of the salts of tartaric acid in alcoholic solutions at low temperatures. The most abundant is potassium acid tartrate or cream of tartar, though calcium tartrate may also precipitate as parts of sediment.
Their presence in quality wines is increasingly accepted because it simply indicates fewer manipulations in the making process (i.e. minimal cold stabilization, non-aggressive filtration, etc.) and, moreover, they carry many beneficial compounds for human health as are polyphenols and tannins. Nevertheless, many consumers do not appreciate their presence in every day wines, considering them as clouds. The process by which they are removed is called tartaric stabilization (cold stabilization, by means of resins, mannoproteins, electrodialysis, etc).
- Filtration (Filtración): The removal of unwanted particles suspended in wine or grape juice. It is one of the most widely employed winemaking techniques to accelerate clarification and stabilization of wines, consisting of the elimination of suspended solids by making the wine run through a filter.
It is usually performed in stages depending on the production phase and the type of filtration. There are basically two kinds, which go from lesser to greater capacity: layer or depth filtrations, usually less aggressive for larger particles (by means of diatomaceous earth, cellulose, press filters, etc.), and membrane filtrations, for micro particles (employing kieselgurs and perlites, by cartridges, millipore, etc.). The former are earned out after fermentation or racking operations, while the latter tend to sterilize wines before bottling.
In quality wines, it is commonly accepted that aggressive filtrations eliminate relevant solid compounds which contribute to their complexity, as well as tannins and colouring matter which aid them to age. An unfiltered wine can throw much sediment and tartrates.
- Bottling (Embotellado): Most common type of packaging wines by filling them into glass bottles, which is one of the essential operations of winemaking. It can be performed manually (very small wineries, large bottle formats, etc.) or by mechanical means (the most usual) with the aid of a bottling machine. In both cases, the dry goods for conditioning the wine (bottle, cork, label, cases, etc.) and the bottling line need be prepared, which if mechanical would basically consist of a bottle washer, filler, corker, labeller, encapsulating and casing machines.
Prior to bottling, it is customary to blend all wines from a specific lot or coupage in a tank, which should be done after analysis of the wine and in a way so as to minimize agitation and aeration to avoid undesirable oxidations and contaminations. To this end, the use of inert gases such as carbon dioxide or nitrogen (blanketing) is frequent, and even the whole process may be sterilized, especially when wines are low in alcohol and/or have important residual sugar levels. Just before bottling, the wines may be filtered, though the higher the quality sought the lesser it is required (or filtration does not take place at all).
Location and time of bottling will be chiefly dependent upon the stipulated ageing requirements of wines, the place where the machinery sits, and economical factors (for instance, when exporting table wines it is far more cheaper to transport them in bulk and carry out bottling closer to destination). Conversely, in high quality wines, the quote "estate bottled" may either be a legal requirement in certain appellations of origin, or it may simply lend them stature.
- Winemaking or Vinification (Elaboración o vinificación): The process of making grape juice into wine.
Name given to the set of operations and methods regulated by law aimed at obtaining wine from grapes and with multiple variations according to the wine styles and types being produced. It is similar to vinification, with the sole difference that in winemaking the practices of ageing in wooden casks and/or barrel fermentation are included. Some of the basic aspects of winemaking (not necessarily in order, nor valid for all wine types) are grape reception, crushing, destemming, sulphating, pressing, alcoholic fermentation, clarification, stabilization, malolactic fermentation, ageing and bottling. In general, winemaking techniques are complemented and named after the resulting wine and are grouped into categories which may be combined such as white, young vintage wine, crianza, sweet, organic wine, sparkling, fortified, liqueur wine, carbonic maceration, rosé, dry, medium-sweet, red, still, etc.
- Maceration or soak (Maceración): The contact of grape skins with the must during fermentation, extracting phenolic compounds including tannins, anthocyanins, and aroma.
Name with which the most traditional method for extraction of aromatic and colouring polyphenols from grape skins is known (and small fragments of seeds and stalks) so as to incorporate them to the wine.
It basically consists of leaving solid substances (particularly skins) in contact with the grape juice before, during and/or after fermentation in order that their soluble compounds pass onto the wine.
A certain degree of maceration is naturally achieved as soon as grapes are crushed and there is a liquid medium or must acting as substrate for extraction. The nature and extraction rates of the compounds are quite diverse and may be dependent upon temperature, duration of contact, agitation (either naturally, by bubbles of carbon dioxide at fermentation, or provoked by man), substrate composition (levels of alcoholic strength attained in musts and/or wines, for high alcohol contents favour extraction), variety, degree of fruit ripeness, desired style and wine colour, etc.
It is crucial in reds, for absence of maceration translates into a colourless wine besides lacking in other distinctive elements. Hence, it is not a common procedure in whites (there is no need for colour and too many coarse and green tannins may be extracted) although some producers of quality white wines do subject their musts to it before fermentation to extract important flavour compounds.
In rosé wines, maceration is deliberately limited to a few hours (less colour). In general, the longer maceration takes place, the higher the degree of extraction (which is never 100% complete) and polymerization, though it should be performed carefully for, in excess, it may harm the wine as a whole. The experience of winemakers becomes then essential during maceration, which should be carried out under constant surveillance and analysis, as well as by employing extraction techniques which are appropriate to the wine type sought.
- Crushing or grinding (Estrujado): After harvest, and prior to pressing, grape are "crushed" or broken up so that the juice is released and allowed to macerate with the skins prior to and during fermentation. In viticultural terms, "Crush" is used as a synonym for harvest time.
Operation performed after selection and reception of grapes in the hopper, which consists of breaking the skins, usually with the aid of machinery equipped with roller blades and with sufficient space for seeds to be left untouched (which impart greenish nuances to the wines), in order to facilitate the extraction of the must and pressing of the grapes (whites, rosés). Crushing may be carried out simultaneously with destemming (red wines), in machines called crushers-destemmers. In the past, the crushing of the grapes was usually done in a lagar by foot treading.
- Stirring or batonnage (Bastoneo): In wines matured in contact with their lees, it describes the practice of stirring them with a stick or rod so as to gain aromatic and flavour complexity.
- Astringency (Astringencia): A wine leaving behind a drying and bitter sensation in the mouth due to high tanins, which have not yet been integrated. "A young and somewhat astringent wine".
- Polyphenols or phenols, or phenolics (Polifenoles): Very reactive substances with more than one phenol group (a benzene ring with a hydroxyl group -OH-) per molecule, which are found in parts of the vine and its fruits. They are generally divided in to flavonoids (flavonols, anthocyans, etc.), tannins (hydrolysable and condensed) and lignins (i.e. some ethers). Their formation in the plant and fruits depends upon multiple factors (climate, temperature, sunlight exposure, low nitrogen contents in soils, etc.) and within them they perform diverse regenerative and protective functions (antioxidant, antiseptic, protection against insect aggressions, recognition for pollination, etc.).
They are complex and formed by hundreds of different molecules, which are passed onto the wine during winemaking, being a determining factor to establish their quality. Phenolic molecules have a great reactive capacity and combine with acids, sugars, as also with other polyphenols to form long-chained colloids and polymers that generate important aromatic and flavour/taste compounds, besides having a deep influence on wine colour.
Phenolic ripeness does not usually coincide with industrial ripeness, and deficiencies in the first are rather more difficult to correct than in the second. Even the formation of anthocyans and tannins do not necessarily coincide during ripening. Grape skins and seeds are the parts with maximal concentration of polyphenols, though they can also be found in the pulp and stalks. If sugar and acid contents in the grape have a direct consequence in the wine, this is not so clear in polyphenols (i.e. concentration of anthocyans in grapes and colour intensity, a relation highly influenced by the wine’s exposure to oxygen). The degree of polyphenol condensation conditions the organoleptic properties of wines and essentially depends on extraction, maturation and oxidation levels. In large concentrations, they become insoluble and precipitate, being part of sediment.
- Anthocyans (Antocianos): Phenolic pigments that give red wine its color. In oenology, flavonoids and soluble polyphenols that originate in the skins of red grapes.
A significant part is transferred into wines during maceration, where they are responsible for the colour of red wines by reaction with other phenolic compounds to which they bind, forming polymers and colloids. Those containing a glucose group are called anthocyanins (a majority in red wines) and those with no sugar, anthocyanidins.
There are manifold factors influencing the exact shade of colour they lend to wines, such as the variety employed, degree of ripeness, extraction techniques, fixed acidity, pH, etc. In general, the lower pH and fixed acidity are, the deeper the colour.
- Tannins (Taninos): Phenolic compound that give wine a bitter, dry, or puckery feeling in the mouth while also acting as a preservative/anti-oxidant and giving wine its structure. It is derived from the seeds (pips), skins and stalks of grapes.
It is a relevant and complex group of polyphenols with a very high ability to interact with polysaccharides and proteins, which are incorporated into the wine either from parts of the vine (including skins, seeds, stalks or stems), or from the wooden casks where it is aged.
They are divided into condensed tannins, which are polymers of proanthocyanidins and cathechins monomers, whilst hydrolysable tannins (which may come from the plant or the barrel) are formed by esthers of phenolic acids. Both are responsible for the bitter taste sensation of wines as for the tactile sensory perceptions of astringency in the mouth, and may form pigmented polymers (i.e. by reaction with anthocyans and catechins) or not.
Their molecules have the capability of binding with proteins and other macromolecules to form strong complexes or colloids by agglomeration and polymerization, thus playing an important role in the formation of wine colour and its backbone.
Tannins (which cannot be smelt) in red wines are far more noticeable on the palate for they are fermented and/or macerated with the skins, some seeds and other parts of stems. They also play a major role in wine ageing as in preventing oxidation, precipitating over time and being part of sediment.
The levels of tannins in wines are measured in terms of gallic acid, and are dependent upon many factors, among which the most relevant are grape variety, extraction methods and barrel type (hydrolysable tannins).
Managing their extraction, concentration and oxidation levels is a fundamental step in achieving quality wines which will be able to taste and age well, without being too bitter or astringent. Paradoxically, oenological tannins may also be used in winemaking as compounds for fining and stabilization.
- Oenological tannins (Taninos enologicos): Natural extracted tannins from either the wood of the oak tree (gallnuts), grape seeds or skins, which may be used in winemaking (under limitations) for clarification, fining and stabilization of wines, contributing to their qualitative development (including the elimination of undesirable greenish tones).
- Cold soak or maceration (Maceración en frío): A technique for extractión of polyphenols (especially aromatic) consisting in cooling and holding the must at a temperature of about 10ºC (50ºF) for several days, witha a generous dosage of sulphur dioxide and under anaerobic conditions, before alcoholic fermentation is triggered.
It is performed in the belief that absence of alcohol and oxygen, along with presence of sulphur, allows for better extraction of complex flavours and aromas. As it is performed in cool temperatures, extraction of anthocyans (pigments responsible for wine colour in red and rosé wines) is quite limited at this stage. This is so because each phenolic compound has its own rate of extraction depending on temperature and substrate composition.
- Crushing or grinding (Estrujado): After harvest, and prior to pressing, grape are "crushed" or broken up so that the juice is released and allowed to macerate with the skins prior to and during fermentation. In viticultural terms, "Crush" is used as a synonym for harvest time.
Operation performed after selection and reception of grapes in the hopper, which consists of breaking the skins, usually with the aid of machinery equipped with roller blades and with sufficient space for seeds to be left untouched (which impart greenish nuances to the wines), in order to facilitate the extraction of the must and pressing of the grapes (whites, rosés).
Crushing may be carried out simultaneously with destemming (red wines), in machines called crushers-destemmers. In the past, the crushing of the grapes was usually done in a lagar by foot treading.
- Destemming / destalking (Despalillado, desgranado, o derrasponado): The winemaking operation of removing larger portions of stalks or stems from musts (or from grapes, by pulling them out), which usually takes place before, during or immediately after crushing.
Although it may be manually performed (as is the case when picking off single grapes for botrytis-affected wines), it is habitually completed by means of specialised machinery, commonly known as a destemmer.
It also defines a wine type or style, whatever its colour. For instance, it may not be carried out when making some red wines, whether young (as by definition in those made by carbonic maceration) or quality craftings intended for ageing in barrel, when grapes and stalks are quite mature (i.e. in many wineries of Burgundy and Rioja).
The latter instance is also valid for some top-notch whites and rosés (as well as when making base wines used for sparkling winemaking), when pressing is carried out onto whole or just slightly-crushed bunches.
It is evident that if destemming does not take place, large proportions of stalks and long contact periods may lead to excess bitterness, astringency and greenish notes in wines (with a greater risk in whites), which is why this process has to be thoroughly controlled, as does the subsequent settling.
Stalks also have a diluting effect on wine colour and alcoholic strength, though they can favour fixing of tannins and other phenolic compounds.
- Vatting (Encubado): In general, putting musts or wines into casks or tanks for winemaking, storing or ageing. In particular, the racking of the must to the fermentation tank with the skins for making red wines.
- De-vatting, devatting (Encubado): The process of separating red must from pomace, which can happen before or after fermentation.
- Pumping over (Remontado): In red winemaking the operation aiming at improving extraction and fermentation by aeration, which consists of drawing off the must from the bottom of the fermentation tank to lift it and subsequently letting it fall onto the cap.
- Pigeage, mashing-down, punching down: Winemaking technique applied to the cap during fermentation, which consists of breaking or punching it down with a stick or rod so as obtain enchanced extraction of tannins and colour in wines.
- Délestage orRack and return (Delestaje o delastrado): French term for racking with the purpose of removing harsh tannins from the wine in the form of grape seeds. In this process the wine is drained into a secondary vessel, allowing the cap to settle to a bottom and loosen the seeds that are trapped in the pulps. As the wine drains, a filter captures the seeds and removes them from the wine. The wine is then returned the first vessel.
In red winemaking, a very energetic technique for handling the cap, aiming at improving extraction of colour and polyphenolic compounds. It basically consists of emptying the fermentation tank during the course of fermentation, so that the cap is compacted at the bottom. One or two hours later, the must/wine is violently pumped back into the tank. Aeration is drastically augmented and so is the solubility of colour and flavour precursors by squashing the skins at higher temperatures. According to the style sought, this procedure will be realised more or less often, though it is not advisable for it to take place at the end of fermentation for too much extraction could prove to be harmful.
- Pomace or bagasse (Orujos): The skins, stalks, and pips (seeds) that remain after making wine. Also called marc.
It debris such as stalks, seeds, pulp and skins which are produced during crushing, destemming or pressing of the grapes, or after the fermentation of wines. In white winemaking, in which it is removed before fermentation, pomace is sweet and fresh.
In reds, which are made with the cap, it includes residues of alcohol and fíne lees. Pomace may either be distilled to produce marc, or may be treated to recuperate tartrates (e.g. cream of tartar), or to obtain colouring agents for the food industry, or even occasionally, to make grapeseed oil.
- Free-run, free run juice, draining or dejuicing (Escurrido): Juice obtained from grapes that have not been pressed.
- Racking (Trasiego): The process of drawing wine off the sediment, such as lees, after fermentation and moving it into another vessel.
Any transfer of musts or wines carried out within the winery from one vessel to another whether before, during or after fermentation (from tanks to other tanks); or whilst they are ageing in barrels (from casks to other casks, or from the latter to tanks).
Winemakers usually take advantage of this racking operations (depending on wine type and the stage of winemaking and ageing) to totally or partially remove sediment, dregs, pomace, skins, tartrates, lees, etc.
The elimination of solids, which contributes to clarification, may be done by precipitation or settling, by filtration, lees racking, etc.
Racking operations are vatting, drawing off, bleeding, draining or "rociado", which are accomplished either with the aid of pumps or by gravity. In all of them, it is important to control aeration in order to avert undesirable oxidations.
- Coupage, blend or blending (Cupaje o mezcla de vinos): Similar to assemblage (another Gallicism), which is more frequently used when making quality sparkling wines. It literally means "cut" wine, which is obtained by blending or homogenization of different wines.
The mixing of two or more different parcels of wine together by winemakers to produce a consistent finished wine that is ready for bottling. Laws generally dictate what wines can be blended together, and what is subsequently printed on the wine label.
It may refer to blends of wines from the same variety but from different wine lots or vine plots, though for the most part it alludes to the blends of different varietal wines from a single vintage year, so that the characteristics of each cultivar and their wines contribute to enhance the final result. In this case coupage is expressed as a percentage of each varietal wine participating in the final wine, under the name of the cultivars that have been employed in its making.
In some instances it may also be expressed as the percentage of different grapes that have been employed in the fermentation of a single wine, though this is not technically coupage.
- Ageing, maturation or breeding (Crianza): Either a most important stage of a wine’s life cycle or a process in winemaking (whether in tanks, barrel or bottle) through which it substantially improves its sensory properties through complex chemical and oxidative reactions. Not all wines get better with ageing, since for this to occur, several interrelated factors need to concur as are a high alcohol content and acidity (which need be balanced), convenient polyphenolic extraction and adequate residual sugar, absence of contaminants, correct tannins, stability, wine colour, aldehydes, temperature, etc.
The set-out is so complex that there is no ageing pattern capable of originating standard and uniform qualities. Each single wine has its own life and maturation cycle, which in general depends upon soil, weather conditions and vine management, grape harvest, varieties employed and winemaking procedures followed. Ageing starts in the tanks or vessels in which wines are clarified and stabilized after fermentation and where oxidative polymerization reactions begin. Ageing in barrel or wood follows, in which all wine components (and especially compounds responsible for colour, aroma and flavour/taste) slowly polymerize forming larger and more stable molecules which refine and improve the final result.
A very special type of dynamic ageing in barrels, by blending different vintages, is the soleras and criaderas system. Last but not least, bottle ageing allows a very slow oxidative development which rounds up the wine completely and facilitates the generation of bouquet, essential for it to be considered as a great or big wine. The profound changes wines experience over time (colour degradation, sediment, suppleness, aromatic and taste complexity, etc.) are unforeseeable, though they can be estimated by skilled tasters and professionals, provided stable and adequate laying down/storing conditions are met.
- Barrel or Barrique (Barrica): Generic and most frequent name given to medium-sized, cylindrical shaped and bulging wooden casks used for the maturation or ageing of wines and spirits. They come in different qualities which may be categorised depending either on the processes and wood employed in their production or on the number of vintages they have been in use, or by their holding capacity.
It is also known as hogshead or drum, though these terms are either becoming obsolete (hogshead) or increasingly used to designate wooden vessels which hold other products different from wines and spirits.
As for sizes, there is also a great diversity. Generally speaking, all wooden containers are casks, vats are the larger ones, which remain permanent and in vertical position, whereas barrels or barriques would be those which can easily be moved by rolling them up and are stored horizontally (e.g. shipping butt, Bordeaux’s barrique, butt, etc.).
A barrel is made up of staves, which are bent and held together with hoops to form a convex cylinder with both ends being firmly closed by rounded flat heads. At least one hole is left for filling o topping up, after extraction of the bung.
Barrels may also be classified according to their level of toast, which so much influences wine aroma and flavour/taste. During ageing, wood conveys part of its natural properties to wines, directed at improving their organoleptic properties.
The majority of barrels are made from oak in a cooperage due to its great malleability and the characteristics it imparts, more precisely from European (genetically known as French oak) or North American species (American oak).
- Toast or toasting (tostado o tueste): The charring of the wine staves during cask manufacture or rejuvenation.
When referring to casks and barrels, process at the cooperage by which the inner part of the vessel is subjected to heating, which affects the physical and chemical properties of the wood and hence of the wines matured within it.
Depending on the length of time toasting is carried out, intensity of the heat source and oak type it will confer different aromas and flavours to the wines. Likewise, the level of use in the winery and the age of the vessel will both attenuate its effects.
In general, the lesser the toast, the greater the extraction of lannins from the wood. Casks usually indicate their degree of toast on the heads: light, medium and heavy. They will be selected and employed by the winemaker according to the wine style sought.
- Topped up or Topping (Rellendado de barricas): The process of filling the headspace that is created inside a barrel through wine evaporation into the Barrel wood.
When referred to barrels, it is the operation which is carried out to limit wine oxidation, and possible growth of acetobacter, which consists of frequently refilling them with wines from the same vintage year during ageing. Wine volume is progressively lost in the barrel through evaporation.
- Polishing (Abrillantado o filtrado): An ultrafine means of filtration usually done with kieselguhr or perlite that leaves a wine with exceptionally bright clarity, giving the impression that it has been polished.
Premium wines will often decline polishing because ultra fine precision can also remove flavor and phenolic compounds that may diminish the quality and aging potential of the wine.
- Picking or harvesting (Cosechar): Action of collecting grapes, manually or mechanically.
- Base wine (Vino base): A still wine, or vin clair, usually fermented to roughly 11 degrees of alcohol, used as a component in the blending of champagne. Champagne is generally blended from many different base wines, sometimes hundreds.
- Cuvée (Vino mezclado): A wine blended from several vats or batches, or from a selected vat. Also used in Champagne to denote the juice from the first pressing of a batch of grapes.
- Liqueur de tirage (Licor de tiraje): French term for a liquid containing saccharose and yeast used to effect the second fermentation in sparkling wine production. A mixture of sugar ans selected yeasts which is added to the base wine so as to provoke a second anaerobic bottle fermentation when making sparkling wines (following the champenoise and transfer methods).
- Secondary fermentation (Fermentación secundaria): Most commonly the term is used to refer to the continuation of fermentation in a second vessel (e.g. moving the wine from a stainless steel tank to an oak barrel).
The Australian meaning of this term is malo lactic fermentation MLF, as distinct from primary fermentation, the conversion of sugar to alcohol.
- Remouage (Removido): The periodic turning or shaking of bottled wine, especially champagne, to move sediment towards the cork.
- Pupitres (Pupitres): An A-frame rack used in the production of sparkling wine. The drilled holes in the boards allow sparkling wine bottles to go through the riddling process to slowly move the leftover sediment from secondary fermentation into the neck for removal.
- Puttonyos: Puttonyos is the unit given to denote the level of sugar and hence the sweetness of Hungarian dessert wine, called Tokaji (or tokay). It is traditionally measured by the number of hods of sweet botrytised or nobly rotted grapes (known as Aszú) added to a barrel of wine, but is now measured in grams of residual sugar. The puttony was actually the 25 kg basket or hod of Aszú grapes, and the more added to the barrel of wine, the sweeter the eventual wine. Measurement goes from 3 to 6 Puttonyos. A Tokaji made entirely from Aszú grapes is known as Aszú Eszencia.
- Riddling or remuage (Removido o remoción): Also known as "Rémuage" in French, part of the Méthode Champenoise process whereby bottles of sparkling wine are successively turned and gradually tilted upside down so that sediment settles into the necks of the bottles in preparation for degorgement.
It is the important procedure in sparkling winemaking by the champenoise method which takes place after the wines have completed bottle fermentation and compulsory ageing in horizontal storage.
The sediment (lees) needs to be pushed to the bottle’s neck for removal. If performed by hand, the bottles are placed on special racks or "pupitres". Bottles are first kept on a 45° angle with respect to the floor, and from time to time they receive coups de poignet or shakings to be again put back into the rack. In about two months, the procedure continues, as the angle is progressively increased, up until bottles are completely upside down and disgorgement takes place. This process may be fully automated by employing gyropalettes.
- Disgorging or disgorgement (Deguelle): One of the final operations taking place in the winemaking process of sparkling wines by the traditional method, which consists in removing sediment and lees after ageing in bottle (horizontal storage). It was traditionally performed by hand, and the bottle neck physically cut off (from where the French term derives). At present bottle necks are frozen, bottles are put in a vertical position, crown stoppers withdrawn and the inner pressure does the rest by making the frozen deposits burst out on their own.
- Crown cap (Tapón corona): A beer bottle cap used as a temporary closure for a sparkling wine as it undergoes as secondary fermentation. Brit an airtight metal seal crimped on the top of most bottled beers, ciders, mineral waters, etc.
