The Wine Making Process
on October 28th, 2009 in wine making tagged
The science or study of wines and winemaking is known as oenology. The wine making process, or vinification, is an elaborate procedure that combines several steps – from the selection of grapes to the bottling of finished wine. Winemaking can be classified into two broad categories: still wine making (without carbonation) and sparkling wine making (with carbonation).
The quality of a wine is highly dependent on the quality of the grapes used to make it. The quality of the grapes is further governed by their variety, the soil, the weather during the growing period and the time of harvest. The grapes are usually harvested in autumn.
Harvesting can be regarded as the first step in the wine making process. Grapes are picked from the vineyard and transferred to the winery in open bins. Grapes can be either harvested by hand or by using machines. However, harvesting grapes by hand ensures that only the best grapes reach the winery.
After the harvest, the grapes are transferred to a destemmer/crusher where the stems are separated from the grapes and the grapes are crushed. After de-stemming and crushing, the grape juice is poured into fermentation vats, where yeast converts most of the sugars in the grape juice into alcohol. This procedure is called primary fermentation and takes about one to two weeks.
After the primary fermentation, the resulting liquid is poured into vessels for secondary fermentation, where the wine becomes clear as the residual sugars are slowly converted into alcohol. After fermentation, some wines are allowed to age in oak barrels or stainless steel tanks, while other are bottled directly.
A winemaker, or vintner, may follow variations on the above procedure depending on his/her target wine style. For instance, with sparkling wines such as Champagne, carbonation (trapping carbon dioxide to create bubbles) takes place inside the bottle. After ageing, the wines are filtered to stabilize them.
The last stage in the wine making process is blending and bottling. This is when the winemaker may rectify inadequacies by mixing wines from different batches in order to achieve the desired aroma and taste. Before bottling, a measured quantity of sulfite is added as a preservative and to prevent undesired fermentation inside the bottle. The wine bottles are then sealed with a cork or screw cap.