As an expert sommelier and brewer, I can confidently say that wine cannot be fermented for too long. Fermentation is a natural process that occurs when yeast converts the sugars in grape juice into alcohol. It continues until all the available sugars have been consumed or until the yeast reaches its alcohol tolerance limit.
During fermentation, yeast consumes sugar and produces alcohol and carbon dioxide as byproducts. The yeast will continue to consume sugar until it is either depleted or the environment becomes unfavorable for its growth. In the case of winemaking, the winemaker usually controls the fermentation process by monitoring the sugar levels and deciding when to stop it.
It is important to note that the length of fermentation can vary depending on the type of wine being produced. For example, white wines are typically fermented for a shorter period compared to red wines. The winemaker's goal is to achieve a balance between alcohol content, acidity, and desired flavors in the final product.
In some cases, winemakers may choose to stop fermentation before all the sugar is consumed, resulting in off-dry or sweet wines. This can be achieved by either chilling the wine to inhibit yeast activity or by adding sulfur dioxide to kill off the yeast. The residual sugar left in the wine gives it a touch of sweetness.
However, it is important to note that if fermentation is stopped too early, there is a risk of residual sugar remaining in the wine, which can lead to refermentation in the bottle. This can result in unwanted carbonation or even the wine becoming completely dry if all the remaining sugar is consumed.
In my experience, I have come across wines that were intentionally left with residual sugar to create a sweet or off-dry style. These wines can be enjoyable and pair well with certain foods or desserts. On the other hand, I have also encountered wines that have undergone an unintentional refermentation in the bottle, resulting in unexpected carbonation and altering the intended flavor profile.
To summarize, while it is not possible to ferment wine for too long, winemakers have the ability to control when to stop fermentation to achieve their desired style. The decision to stop fermentation and the amount of residual sugar left in the wine is a crucial step in winemaking, as it greatly influences the final taste and sweetness of the wine.