Color (wine) in the context of Maturation (wine)

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 (sparkling, still, fortified, rosé, dessert wine, etc.) 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.

There are several factors that contribute to the ripeness of the grape. As the grapes go through veraison, sugars in the grapes will continue to rise as acid levels fall. The balance between sugar (as well as the potential alcohol level) and acids is considered one of the most critical aspects of producing quality wine so both the must weight and "total acidity", as well as the pH of the grapes, are evaluated to determine ripeness. Towards the end of the 20th century, winemakers and viticulturists began focusing on the concept of achieving "physiological" ripeness in the grapes-described as a more complete ripeness of tannins and other phenolic compounds in the grapes that contribute to the color, flavor and aroma of wine.

Grenache (/ɡrəˈnæʃ/, pronounced [ɡʁənaʃ] ) or Garnacha (pronounced [ɡaɾˈnatʃa]) is one of the most widely planted red wine grape varieties in the world. It ripens late, so it needs hot, dry conditions such as those found in Spain, where the grape is believed to have originated. It is also grown in the Italian island of Sardinia, the south of France, Australia, and California's Monterey AVA, Paso Robles, Santa Barbara County and San Joaquin Valley.

It is generally spicy, berry-flavored and soft on the palate and produces wine with a relatively high alcohol content, but it needs careful control of yields for best results. Characteristic flavor profiles on Grenache include red fruit flavors (raspberry and strawberry) with a subtle, white pepper spice note. Grenache wines are highly prone to oxidation, with even young examples having the potential to show browning (or "bricking") coloration that can be noticed around the rim when evaluating the wine at an angle in the glass. As Grenache ages the wines tend to take on more leather and tar flavors. Wines made from Grenache tend to lack acid, tannin and color, and it is often blended with other varieties such as Syrah, Carignan, Tempranillo, and Cinsaut.

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. There are exceptions, such as the case of sparkling wine production in regions such as Champagne where grapes are traditionally whole-cluster pressed with stems included to produce a lighter must that is low in phenolics.

In white wine production, pressing usually takes place immediately after crushing and before primary fermentation. In red wine production, the grapes are also crushed but pressing usually doesn't take place until after or near the end of fermentation with the time of skin contact between the juice and grapes leaching color, tannins and other phenolics from the skin. Approximately 60-70% of the available juice within the grape berry, the free-run juice, can be released by the crushing process and doesn't require the use of the press. The remaining 30-40% that comes from pressing can have higher pH levels, lower titratable acidity, potentially higher volatile acidity and higher phenolics than the free-run juice depending on the amount of pressure and tearing of the skins and will produce more astringent, bitter wine.

Phenolic compounds—natural phenol and polyphenols—occur naturally in wine. These 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 (enocyanin), flavanol monomers (catechins) and flavanol polymers (proanthocyanidins). This large group of natural phenols can be broadly separated into two categories, flavonoids and non-flavonoids. Flavonoids include the anthocyanins and tannins which contribute to the color and mouthfeel of the wine. The non-flavonoids include the stilbenoids such as resveratrol and phenolic acids such as benzoic, caffeic and cinnamic acids.