Winemaking is the process of turning grape juice into wine. There are are myriad of styles, options and choices that a winemaker to shape the final product. There are entire winemaking school-of-thought that the best wines are ‘natural’ and many seek ‘low-intervention’, organic and or biodynamic practices to bring a harmonious cultivation of the grape vine and making wine.
The common winemaking process is as follows:
Crushing– by splitting rape skins, the juice gets released.
Pressing– pressed grapes are squeezed into a press to extract as much liquid as possible. This stage is either before or after fermentation, respectively. For red wines, pressing occurs after fermentation. For white wines, pressing occurs before and rose wines are pressed after a short maceration (time on skins) and remaining juice continues to ferment.
Alcoholic Fermentation– The process that creates alcohol and is the common thread between all wines. It is made possible by microorgansims called yeast. Another byproduct is Carbon Dioxide and Heat. When the yeast has consumed all the sugar, the yeast die off and fermentation stops naturally. This will result in a dry wine. The level of alcohol in a wine depends on how much sugar there is in the grapes. Alcohol levels in most dry wines range from 11.5-16%.
Storage/Maturation-Newly made wine is stored for a period of time in a vessel. The time can range from a few months to years. Maturation is applied to wines that are held for an extended period of time.
Most wines take 5–21 days to ferment sugar into alcohol. A few rare examples, such as Vin Santo and Amarone, take anywhere from 50 days to up to 4 years to fully ferment!
After the fermentation, vintners drain the freely running wine from the tank and put the remaining skins into a wine press. Pressing the skins gives winemakers about 15% more wine!
Winery Vessels:
Stainless Steel or concrete vessel– These can be used for both fermentation and storage. They are both inert and do not add any flavor to the wine. They can also be adjusted to be airtight, therefore blocking oxygen to interact with the wine.
Oak Vessels- wooden vessels can be used for both fermentation and storage. Most are made out of oak and there are two main reasons a winemakers would use a barrel. First, oak can add flavors directly to the wine and second, it can also allow flavors to evolve as a result of the interaction between wine with oxygen during maturation.
Choices of Toast, Age, Type and Size– The more toasted the barrel, the more intense the flavors will be imparted on the wine. Toasting can produce sweet-spice and charred wood aromas and flavors. If a barrel is new and has not been used before it can a lot of flavor to the wine. These flavors can include vanilla, coconut, charred wood, and spice. If a barrel has been used before, the barrel will add less flavor to the wine. Oak vessels are water-tight but not airtight, meaning that during maturation, oxygen from the atmosphere can enter the barrel and interact with the wine. The interaction of air to wine can add oxidative flavors like caramel, dried fruit, and nutty flavors to develop.
Wine Making Process Video: One Year at a Vineyard and Winery