Phenolic content in wineThe phenolic content in wine refers to the phenolic compounds—natural phenol and polyphenols—in wine, which include a large group of several hundred chemical compounds that affect the taste, color and mouthfeel of wine. These compounds include phenolic acids, stilbenoids, flavonols, dihydroflavonols, anthocyanins, flavanol monomers (catechins) and flavanol polymers (proanthocyanidins). This large group of natural phenols can be broadly separated into two categories, flavonoids and non-flavonoids.
Yeast in winemakingThe 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.
Fermentation in winemakingThe 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 (as a by-product). 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.
Wine faultA wine fault is a sensory-associated (organoleptic) characteristic of a wine that is unpleasant, and may include elements of taste, smell, or appearance, elements that may arise from a "chemical or a microbial origin", where particular sensory experiences (e.g., an off-odor) might arise from more than one wine fault. Wine faults may result from poor winemaking practices or storage conditions that lead to wine spoilage.
TerroirTerroir (tɛˈrwɑːr, tɛʁwaʁ; from terre, "land") is a French term used to describe the environmental factors that affect a crop's phenotype, including unique environment contexts, farming practices and a crop's specific growth habitat. Collectively, these contextual characteristics are said to have a character; terroir also refers to this character. Some artisanal crops for which terroir is studied include wine, cider, coffee, tobacco, olive oil, chocolate, chili peppers, hops, agave (for making tequila and mezcal), tomatoes, heritage wheat, maple syrup, tea, and cannabis.
WinemakingWinemaking (also wine making) 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. Winemaking can be divided into two general categories: still wine production (without carbonation) and sparkling wine production (with carbonation – natural or injected).
Harvest (wine)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.
Pressing (wine)In winemaking, pressing is the process where juice is extracted from the grapes with the aid of a wine-press, by hand, or even by the weight of the grape berries and clusters. Historically, intact grape clusters were trodden by feet but in most wineries today the grapes are sent through a crusher/destemmer, which removes the individual grape berries from the stems and breaks the skins, releasing some juice, prior to being pressed.
VarietalA varietal wine is a wine made primarily from a single named grape variety, and which typically displays the name of that variety on the wine label. Examples of grape varieties commonly used in varietal wines are Cabernet Sauvignon, Chardonnay and Merlot. Wines that display the name of two or more varieties on their label, such as a Chardonnay-Viognier, are blends and not varietal wines. The term is frequently misused in place of vine variety; the term variety refers to the vine or grape, while varietal refers to the wine produced by a variety.
PomacePomace (ˈpʌməs ), or marc (ˈmɑrk; from French marc maʁ), is the solid remains of grapes, olives, or other fruit after pressing for juice or oil. It contains the skins, pulp, seeds, and stems of the fruit. Grape pomace has traditionally been used to produce pomace brandy (such as grappa, orujo, törkölypálinka, zivania). Today, it is mostly used as fodder, as fertilizer, or for the extraction of bioactive compounds like polyphenols. The English word derives from Medieval Latin pomaceum ("cider") and pomaceus ("pomaceous, appley"), from Classical Latin ("fruit, apple").
