Index of all articles, click here
Winemaking, or vinification, is the production of wine, starting with selection of the grapes or other produce and ending with bottling the finished wine. Although most wine is made from grapes, it may also be made from other fruit or non-toxic plant material. Mead is a wine that is made with honey being the primary ingredient after water.
Winemaking can be divided into two general categories: still wine production (without carbonation) and sparkling wine production (with carbonation).
The science of wine and winemaking is known as oenology. A person who makes wine is traditionally called a winemaker or vintner.
After the harvest, the grapes are taken into a winery and prepared for primary ferment. At this stage red wine making diverges from white wine making. Red wine is made from the must (pulp) of red or black grapes that undergo fermentation together with the grape skins. White wine is made by fermenting juice which is made by pressing crushed grapes to extract a juice; the skins are removed and play no further role. Occasionally white wine is made from red grapes; this is done by extracting their juice with minimal contact with the grapes' skins. Rosé wines are either made from red grapes where the juice is allowed to stay in contact with the dark skins long enough to pick up a pinkish color (blanc de noir) or by blending red wine and white wine. White and rosé wines extract little of the tannins contained in the skins.
To start primary fermentation yeast may be added to the must for red wine or may occur naturally as ambient yeast on the grapes or in the air. Yeast may be added to the juice for white wine. During this fermentation, which often takes between one and two weeks, the yeast converts most of the sugars in the grape juice into ethanol (alcohol) and carbon dioxide. The carbon dioxide is lost to the atmosphere.
After the primary fermentation of red grapes the free run wine is pumped off into tanks and the skins are pressed to extract the remaining juice and wine. The press wine is blended with the free run wine at the winemaker's discretion. The wine is kept warm and the remaining sugars are converted into alcohol and carbon dioxide.
The next process in the making of red wine is secondary fermentation. This is a bacterial fermentation which converts malic acid to lactic acid. This process decreases the acid in the wine and softens the taste of the wine. Red wine is sometimes transferred to oak barrels to mature for a period of weeks or months; this practice imparts oak aromas to the wine. The wine must be settled or clarified and adjustments made prior to filtration and bottling.
The time from harvest to drinking can vary from a few months for Beaujolais nouveau wines to over twenty years for top wines. However, only about 10% of all red and 5% of white wine will taste better after five years than it will after just one year. Depending on the quality of grape and the target wine style, some of these steps may be combined or omitted to achieve the particular goals of the winemaker. Many wines of comparable quality are produced using similar but distinctly different approaches to their production; quality is dictated by the attributes of the starting material and not necessarily the steps taken during vinification.
Variations on the above procedure exist. With sparkling wines such as Champagne, an additional fermentation takes place inside the bottle, trapping carbon dioxide and creating the characteristic bubbles. Sweet wines are made by ensuring that some residual sugar remains after fermentation is completed. This can be done by harvesting late (late harvest wine), freezing the grapes to concentrate the sugar (ice wine), or adding a substance to kill the remaining yeast before fermentation is completed; for example, high proof brandy is added when making port wine. In other cases the winemaker may choose to hold back some of the sweet grape juice and add it to the wine after the fermentation is done, a technique known as süssreserve.
The process produces wastewater, pomace, and lees that require collection, treatment, and disposal or beneficial use.
As with the rise of brewing one's own beer, many people have taken on the rewarding hobby of amateur winemaking. Winemaking equipment can be purchased from homebrew and wine shops for around $100, and winemaking kits derived from fruit juice concentrates range from $70–$200, depending on the varietal and region of the grape. These kits will make about 30 - 750 ml bottles of wine, at a price of about $3–$8 per bottle.The wine kits and the equipment such as glass and plastic carboys are geared to produce 23 litres of wine. Juices can be purchased in six gallon pails for forty five to sixty dollars a pail. Five pound bags of sugar can cost several dollars and yeast for about one dollar. Five gallon (23 litre) glass jugs can cost about thirty dollars along with a stopper and air lock.
The quality of the grapes determines the quality of the wine more than any other factor. Grape quality is affected by variety as well as weather during the growing season, soil minerals and acidity, time of harvest, and pruning method. The combination of these effects is often referred to as the grape's terroir.
Grapes are usually harvested from the vineyard from early September until early November in the northern hemisphere, and mid February until early March in the southern hemisphere. In some cool areas in the southern hemisphere, for example Tasmania, harvesting extends into May.
The most common species of wine grape is Vitis vinifera, which includes nearly all varieties of European origin.
This article uses material from the Wikipedia article "Winemaking", which is released under the Creative Commons Attribution-Share-Alike License 3.0.