Chardonnay is a green-skinned grape variety used in the production of white wine. The variety originated in the Burgundy wine region of eastern France, but is now grown wherever wine is produced, from England to New Zealand. For new and developing wine regions, growing Chardonnay is seen as a 'rite of passage' and an easy entry into the international wine market.
Winemaking or vinification is the production of wine, starting with the selection of the fruit, its fermentation into alcohol, and the bottling of the finished liquid. The history of wine-making stretches over millennia. The science of wine and winemaking is known as oenology. A winemaker may also be called a vintner. The growing of grapes is viticulture and there are many varieties of grapes.
Carbonic maceration is a winemaking technique, often associated with the French wine region of Beaujolais, in which whole grapes are fermented in a carbon dioxide rich environment before crushing. Conventional alcoholic fermentation involves crushing the grapes to free the juice and pulp from the skin with yeast serving to convert sugar into ethanol. Carbonic maceration ferments most of the juice while it is still inside the grape, although grapes at the bottom of the vessel are crushed by gravity and undergo conventional fermentation. The resulting wine is fruity with very low tannins. It is ready to drink quickly but lacks the structure for long-term aging. In extreme cases such as Beaujolais nouveau, the period between picking and bottling can be less than six weeks.
Red wine is a type of wine made from dark-colored grape varieties. The color of the wine can range from intense violet, typical of young wines, through to brick red for mature wines and brown for older red wines. The juice from most purple grapes is greenish-white, the red color coming from anthocyan pigments present in the skin of the grape. Much of the red wine production process involves extraction of color and flavor components from the grape skin.
Malolactic conversion is a process in winemaking in which tart-tasting malic acid, naturally present in grape must, is converted to softer-tasting lactic acid. Malolactic fermentation is most often performed as a secondary fermentation shortly after the end of the primary fermentation, but can sometimes run concurrently with it. The process is standard for most red wine production and common for some white grape varieties such as Chardonnay, where it can impart a "buttery" flavor from diacetyl, a byproduct of the reaction.
Agiorgitiko is a red Greek wine grape variety that, as of 2012, was the most widely planted red grape variety in Greece, ahead of Xynomavro. The grape has traditionally been grown in the Nemea region of the Peloponnese but can be found throughout the country including Attikí (Attica) and Makedonía (Macedonia).
Maceration is the winemaking process where the phenolic materials of the grape—tannins, coloring agents (anthocyanins) and flavor compounds—are leached from the grape skins, seeds and stems into the must. To macerate is to soften by soaking, and maceration is the process by which the red wine receives its red color, since raw grape juice is clear-grayish in color. In the production of white wines, maceration is either avoided or allowed only in very limited manner in the form of a short amount of skin contact with the juice prior to pressing. This is more common in the production of varietals with less natural flavor and body structure like Sauvignon blanc and Sémillon. For Rosé, red wine grapes are allowed some maceration between the skins and must, but not to the extent of red wine production.
A wine fault or defect is an unpleasant characteristic of a wine often resulting from poor winemaking practices or storage conditions, and leading to wine spoilage. Many of the compounds that cause wine faults are already naturally present in wine but at insufficient concentrations to be of issue. In fact, depending on perception, these concentrations may impart positive characters to the wine. However, when the concentration of these compounds greatly exceeds the sensory threshold, they replace or obscure the flavors and aromas that the wine should be expressing. Ultimately the quality of the wine is reduced, making it less appealing and sometimes undrinkable.
Secondary fermentation is a process commonly associated with winemaking, which entails a second period of fermentation in a different vessel than the one used to start the fermentation process. An example of this would be starting fermentation in a carboy or stainless steel tank and then moving it over to oak barrels. Rather than being a separate, second fermentation, this is most often one single fermentation period that is conducted in multiple vessels. However, the term does also apply to procedures that could be described as a second and distinct fermentation period.
The process of fermentation in winemaking turns grape juice into an alcoholic beverage. During fermentation, yeasts transform sugars present in the juice into ethanol and carbon dioxide. In winemaking, the temperature and speed of fermentation are important considerations as well as the levels of oxygen present in the must at the start of the fermentation. The risk of stuck fermentation and the development of several wine faults can also occur during this stage, which can last anywhere from 5 to 14 days for primary fermentation and potentially another 5 to 10 days for a secondary fermentation. Fermentation may be done in stainless steel tanks, which is common with many white wines like Riesling, in an open wooden vat, inside a wine barrel and inside the wine bottle itself as in the production of many sparkling wines.
The use of wine tasting descriptors allows the taster to qualitatively relate the aromas and flavors that the taster experiences and can be used in assessing the overall quality of wine. Wine writers differentiate wine tasters from casual enthusiasts; tasters attempt to give an objective description of the wine's taste, casual enthusiasts appreciate wine but pause their examination sooner than tasters. The primary source of a person's ability to taste wine is derived from their olfactory senses. A taster's own personal experiences play a significant role in conceptualizing what they are tasting and attaching a description to that perception. The individual nature of tasting means that descriptors may be perceived differently among various tasters.
The harvesting of wine grapes (Vintage) is one of the most crucial steps in the process of wine-making. The time of harvest is determined primarily by the ripeness of the grape as measured by sugar, acid and tannin levels with winemakers basing their decision to pick based on the style of wine they wish to produce. The weather can also shape the timetable of harvesting with the threat of heat, rain, hail, and frost which can damage the grapes and bring about various vine diseases. In addition to determining the time of the harvest, winemakers and vineyard owners must also determine whether to use hand pickers or mechanical harvesters. The harvest season typically falls between August & October in the Northern Hemisphere and February & April in the Southern Hemisphere. With various climate conditions, grape varieties, and wine styles the harvesting of grapes could happen in every month of the calendar year somewhere in the world. In the New World it is often referred to as the crush.
The annual growth cycle of grapevines is the process that takes place in the vineyard each year, beginning with bud break in the spring and culminating in leaf fall in autumn followed by winter dormancy. From a winemaking perspective, each step in the process plays a vital role in the development of grapes with ideal characteristics for making wine. Viticulturalists and vineyard managers monitor the effect of climate, vine disease and pests in facilitating or impeding the vine's progression from bud break, flowering, fruit set, veraison, harvesting, leaf fall and dormancy-reacting if need be with the use of viticultural practices like canopy management, irrigation, vine training and the use of agrochemicals. The stages of the annual growth cycle usually become observable within the first year of a vine's life. The amount of time spent at each stage of the growth cycle depends on a number of factors-most notably the type of climate and the characteristics of the grape variety.
Sugars in wine are at the heart of what makes winemaking possible. During the process of fermentation, sugars from wine grapes are broken down and converted by yeast into alcohol (ethanol) and carbon dioxide. Grapes accumulate sugars as they grow on the grapevine through the translocation of sucrose molecules that are produced by photosynthesis from the leaves. During ripening the sucrose molecules are hydrolyzed (separated) by the enzyme invertase into glucose and fructose. By the time of harvest, between 15 and 25% of the grape will be composed of simple sugars. Both glucose and fructose are six-carbon sugars but three-, four-, five- and seven-carbon sugars are also present in the grape. Not all sugars are fermentable, with sugars like the five-carbon arabinose, rhamnose and xylose still being present in the wine after fermentation. Very high sugar content will effectively kill the yeast once a certain (high) alcohol content is reached. For these reasons, no wine is ever fermented completely "dry". Sugar's role in dictating the final alcohol content of the wine sometimes encourages winemakers to add sugar during winemaking in a process known as chaptalization solely in order to boost the alcohol content – chaptalization does not increase the sweetness of a wine.
This glossary of winemaking terms lists some of terms and definitions involved in making wine, fruit wine, and mead.
In winemaking, clarification and stabilization are the processes by which insoluble matter suspended in the wine is removed before bottling. This matter may include dead yeast cells (lees), bacteria, tartrates, proteins, pectins, various tannins and other phenolic compounds, as well as pieces of grape skin, pulp, stems and gums. Clarification and stabilization may involve fining, filtration, centrifugation, flotation, refrigeration, pasteurization, and/or barrel maturation and racking.
In viticulture, ripeness is the completion of the ripening process of wine grapes on the vine which signals the beginning of harvest. What exactly constitutes ripeness will vary depending on what style of wine is being produced and what the winemaker and viticulturist personally believe constitutes ripeness. Once the grapes are harvested, the physical and chemical components of the grape which will influence a wine's quality are essentially set so determining the optimal moment of ripeness for harvest may be considered the most crucial decision in winemaking.
The role of yeast in winemaking is the most important element that distinguishes wine from fruit juice. In the absence of oxygen, yeast converts the sugars of the fruit into alcohol and carbon dioxide through the process of fermentation. The more sugars in the grapes, the higher the potential alcohol level of the wine if the yeast are allowed to carry out fermentation to dryness. Sometimes winemakers will stop fermentation early in order to leave some residual sugars and sweetness in the wine such as with dessert wines. This can be achieved by dropping fermentation temperatures to the point where the yeast are inactive, sterile filtering the wine to remove the yeast or fortification with brandy or neutral spirits to kill off the yeast cells. If fermentation is unintentionally stopped, such as when the yeasts become exhausted of available nutrients and the wine has not yet reached dryness, this is considered a stuck fermentation.
Yeast assimilable nitrogen or YAN is the combination of free amino nitrogen (FAN), ammonia (NH3) and ammonium (NH4+) that is available for a yeast, e.g. the wine yeast Saccharomyces cerevisiae, to use during fermentation. Outside of the fermentable sugars glucose and fructose, nitrogen is the most important nutrient needed to carry out a successful fermentation that doesn't end prior to the intended point of dryness or sees the development of off-odors and related wine faults. To this extent winemakers will often supplement the available YAN resources with nitrogen additives such as diammonium phosphate (DAP).
Wine preservatives are used to preserve the quality and shelf life of bottled wine without affecting its taste. Specifically, they are used to prevent oxidation and bacterial spoilage by inhibiting microbial activity.
