Wine Tanks Used in the Fermentation Process
During the fermentation process, the cellar manager can choose from oak, enameled metal, stainless steel, concrete, or even plastic wine tanks. Each tank has its own advantages and disadvantages. The widely used stainless steel cabinets have the advantage of being easy to clean and cool, but it is now possible to install temperature control devices in oak cabinets to maintain a stable temperature that is not easily achieved with stainless steel metals.
In order to make rare white wines with long aging potential, French winemakers use oak barrels. Winemakers in the region have been making “small quantities” of fine white wines, especially long-lived white wines made from Chardonnay varieties.
A “small amount” (about 228 liters) is the ideal amount for making white wine. It does not require temperature regulation: the temperature can be raised to 25°C and is always maintained at that temperature. The direct contact between the fermentation process and the oak gives the wine a special flavour. This method of winemaking allows the wine to remain in the mash (the fine sediment produced during fermentation), which prevents oxidation of the pulp and creates a full-bodied taste.
The winemaker often stirs the wine with a “stick” to ensure that the wine is in full contact with the mud, giving the wine a rich structure and a thick texture. This is commonly referred to as the “stick blending process”. Often, after trying to make wine in stainless steel tanks, prestigious wineries are slowly returning to the traditional method of making wine in oak tanks.
Secondary Malolactic Fermentation
Normally, after alcoholic fermentation, wines with high acidity undergo a secondary lactic fermentation to reduce the acidity, but rarely in hot areas, which can affect the fruit expression of the wine. In general, white wines should be made without stirring the wine repeatedly to avoid bacterial contamination.
At the end of the winemaking process, a small amount of sulfur dioxide can be added to prevent oxidation, and the wine can be centrifuged to remove impurities or microfiltered and finally filled aseptically.
Barrel Pouring Process
The fermentation and winemaking process can now be said to be complete. However, the wine still needs to be clarified. It consists of a wine sludge composed of precipitated impurities such as yeast. After the fermentation process, the wine sludge settles at the bottom of the wine tank. The wine is removed from the tank to separate out the precipitated impurities. This operation is known as the barrel pouring process.
This operation is repeated several times during the incubation process. Some wine making processes, such as the muscadet variety from Nantes, France, require incubation in wine mud until bottling. This method gives the wine a unique flavor profile, such as the presence of tiny air bubbles that make the wine fresher and cooler.
The details make the difference, and winemaking is no exception.
