Learn How White Wine is Made
White wine can be made from any color grapes, even red grapes, as long as there is no contact with the skin of red grapes or maceration.
When making wine, the grapes are picked and sorted, the rotten ones discarded. The grapes are then quickly taken to the winery, to avoid being crushed by their own weight and then oxidizing.
If a winemaker is going for a lighter, unwooded style of dry white wine, the grapes are crushed and then seperated from their stalks by a crusher or a de-stemmer. Sulfur dioxide is then added to the grape juice to prevent the juice from oxidizing and spoiling. The sulfur dioxide helps to kill bacteria and any unwanted wild yeasts.
Sometimes when a bottle of wine is opened, you get a whiff of burnt matches. The smell is the sulfur dioxide. Once the wine is allowed to breathe a little, the smell quickly goes away.
The crushed grapes are then pressed, which forces the juice out, while leaving the skins. The grape juice is then pumped into a cold stainless steel tank and allowed to settle. Yeast is then added. Winemakers have the option of using either “wild” yeasts or cultured yeasts. Most winemakers today use cultured yeasts, because they are more predictable. Some winemakers who choose to use “wild” yeasts argue that using “wild” yeasts gives a wine more complexity.
Fermentation begins once the yeasts is added. The fermentation can be slow, warm, slow or cool. The normal temperatures for white wines is 50-77 degrees Farenheit (10-25 degrees Celcius).
Modern wineries can monitor and control the temperature of each vat through control panels. The winemaker can dictate the flavors and the character of a wine by controlling the fermentation temperatures. In general, cooler fermentation temperatures produce wines with a fruitier character. White wines, which mainly depend on primarily on fruit aromas, are almost always fermented at cooler temperatures than most red wines.
Fermentation can take between a few days and a few weeks, with a few days being more common.
The winemaker then pumps the top of the level of the wine into another tank and leaves the lees (dead yeast cells and other sediment that has settled at the bottom of the tank).
The temperature is then lowered, and a claryfying agent, such as egg whites, is added to gather up any other gunk that is floating around any extra sediment that may be floating in the wine. This process is called finning. Any clarifying agent that is added is later removed.
Grapes that did not receive enough when they were on the vine may be relatively low in its’ grape sugars, when this happens, sugar may be added to increase the alcohol level. This is called chaptalization. If these is not enough acidity in the wine, tartaric or citric acid can be added to balance the wine. This is called acidification. A winemaker can choose to do chaptalization or acidification, but not both.
The wine is then filtered and bottled.
Making Full-Bodied White Wine
To make full-bodied, wooded white wine, the process is followed up until the stage of fermentation. Before fermentation is finished, the wine is then pumped into oak barrels. The wine stays in the wine barrels for around 6 to 8 months to absorb the oaky vanilla flavors and to add complexity and character to the wine. Tannin is also absorbed by the wine, which allows the wine to age. Not all white wines are suitable to be aged in oak barrels.
The wine is then pumped into a tank, like before, then stabilized, fined, filtered and then bottled.
More on Oak Barrels
The type and size of the oak barrel that the winemaker chooses has a big influence on the flavors and character of the wine. New barrels give the wine a more oaky flavor than old barrels. Smaller wine barrels give the wine a more oaky flavor than larger wine barrels. American oak gives wine a more powerfull, oaky flavor as compared to French barrels. Oak barrels from one forest differ from oak barrels from another forest.
Oak barrels, of course, cost money, and winemakers sometimes look for a cheaper way to add woodsy qualities to their white wines. Some winemakers will use oak chips or staves. When dry white wine is fermenting in stainless steel tanks, winemakers may add oak chips or staves to the wine to add an oak flavoring. This, however, does not add the complexity and character that comes with aging wine in oak barrels.
Each winemaker has his or her own way of doing things, and skill level, which contribute to the wines’ style. The temperature of fermentation, the length of time in which the wine is allowed to ferment, the choice of barrel (if any) that is used, the strain of yeast that is used, and more, are part of a winemaker’s style.
Almost all red wines, and some white wines (mostly wooded), undergo this second, “softening” fermentation. During malolactic fermentation, the crisp, hard malic acid is converted by bacteria to much softer, lactic acid. This can happen naturally, but winemakers can choose to induce it. This can be done by either keeping the new wine at relatively high temperatures, and/or by deliberately introducing the lactic bacteria. As well as making the wine more stable, malolactic fermentation also makes the wine taste softer, fuller and more complex. When winemakers overdo this, the wine becomes too buttery.
A winemaker can choose to add a little bit of complexity to the wine by stirring up the lees at the bottom of the wine.