Wine-making or vinification, is the production of wine, beginning with the selection of grapes or other products and ending with the bottling of finished wine. Although most wine is made from grapes, it can also be from other fruits or plants. Mead is a wine made with honey being the main ingredient after water. Wine-making can be divided into two general categories: dry wine production (without carbonation) and sparkling wine (with carbonation - natural or injected). The science of wine and wine-making is known as oenology. A person who makes wine is traditionally called an oenologist or winemaker.
Process
After harvest, the grapes are taken to a hold and prepared for the primary yeast. At this stage the elaboration of the red wine diverges from the elaboration of the white wine. The red wine is made from the must (pulp) of the red or black grapes and the fermentation occurs along with the skins of the grape, which give the wine its color. White wine is made by fermenting the juice that is made by pressing the crushed grapes to extract a juice; The skins are removed and do not play any role anymore. Occasionally white wine is made from red grapes; This is done by extracting their juice with minimal contact with the skins of the grapes. Rosé wines are made from red grapes where the juice is allowed to remain in contact with dark skins long enough to collect a pink color (maceration or saignée) or mixing red wine with white wine. The white and rosé wines extract little of the tannins contained in the skins.
To initiate the primary fermentation the yeast can be added to the must for the red wine or it can naturally occur as yeast environment in the grape or in the air. Yeast can be added to juice for white wine. During this fermentation, which often takes between one and two weeks, the yeast converts most of the sugars into grape juice into ethanol (alcohol) and carbon dioxide. Carbon dioxide is lost in the atmosphere.
After the primary fermentation of the red grapes the free wine is pumped into tanks and the skins are pressed to extract the rest of the juice and the wine. Press wine is blended with free running wine at the winemaker's discretion. The wine stays warm and the remaining sugars are converted to alcohol and carbon dioxide.
The next process in the elaboration of red wine is malo-lactic conversion. It is a bacterial process that converts malic acid "crisp green apple" into "soft, creamy" lactic acid, softening the taste of wine. Red wine is sometimes transferred to oak barrels to mature for a period of weeks or months; This practice imparts aromas of oak and some tannins to the wine. The wine must be seated or clarified and adjustments must be made prior to bottling.
Harvest time to drink can range from a few months for Beaujolais nouveau wines to over twenty years for good structure wine with high levels of acid, tannin or sugar. However, only about 10% of all red wine and 5% of white wine will taste better after five years than it will be after only a year. Depending on the grape quality and target wine style, some of these steps can be combined or omitted to achieve the winemaker's particular goals. Many wines of comparable quality are produced using similar but different approaches to their production; The quality is dictated by the attributes of the starting material and not necessarily by the steps given during the vinification.
There are variations in the above procedure. With sparkling wines like champagne, an additional "secondary" fermentation takes place inside the bottle, dissolving carbon dioxide trapped in the wine and creating characteristic bubbles. Sweet wines or dry wines are made by stopping the fermentation before all the sugar is converted into ethanol and leaving some residual sugar left. This can be done by cooling the wine and adding sulfur and other additives allowed to inhibit the activity of the yeast or the sterile wine filter to remove all yeasts and bacteria. In the case of sweet wines, initial concentrations of sugar are increased by late harvesting, freezing the grapes to concentrate the sugar (ice wine), allowing or encouraging the fungus botrytis cinerea to dehydrate the grapes or allow the grapes to The vine or on shelves or straw mats. Often in these high sugar wines, the fermentation stops naturally as the high concentration of sugar and the increasing concentration of ethanol slow down the activity of the yeast. Similarly, in fortified wines, such as port wine, high-grade neutral brandy (brandy) alcohol is added to stop fermentation and adjust the alcohol content when the desired sugar level has been reached. In other cases, the winemaker may opt to retain part of the sweet grape juice and add it to the wine after fermentation, a technique known in Germany as süssreserve.
The process produces wastewater, marc and lees that require collection, treatment and disposal or beneficial use.