As a sommelier and brewer, I can confidently say that white wine does not necessarily go bad once it is opened, but it does begin to deteriorate over time. The oxidation process starts as soon as the bottle is opened and the wine comes into contact with oxygen. This can lead to the wine becoming flat, losing its aroma and flavors, and ultimately becoming undrinkable.
The speed at which white wine oxidizes can vary depending on several factors. One important factor is the type of white wine. Full-bodied white wines, such as Chardonnay and Muscat, are more likely to oxidize quickly because they have been exposed to more oxygen during the aging process. On the other hand, lighter white wines like Sauvignon Blanc and Pinot Grigio may last a bit longer once opened.
Another factor that affects the lifespan of an opened white wine is how it is stored after opening. If you re-cork the bottle and store it in the refrigerator, the wine can last for three to five days. The cooler temperature slows down the oxidation process and helps preserve the wine's freshness to some extent. However, it is important to note that even when stored properly, the wine will gradually lose its vibrancy and complexity with each passing day.
It is worth mentioning that the quality of the wine also plays a role in how long it can last once opened. Higher quality white wines, with more acidity and structure, tend to have a longer shelf life compared to lower quality wines. This is because acidity acts as a natural preservative, helping to slow down the oxidation process.
I have personally experienced situations where I have opened a bottle of white wine and enjoyed it over the course of a few days. However, I have noticed that the wine's flavors and aromas start to diminish after the second or third day. It becomes less vibrant and lacks the freshness that was present when the bottle was first opened.
To summarize, white wine does not go bad once opened, but it does deteriorate over time due to oxidation. Full-bodied white wines are more prone to oxidation and may only last a few days after opening, while lighter white wines may last a bit longer. Storing the opened bottle in the refrigerator can help prolong its lifespan, but it is important to consume it within three to five days to enjoy its optimal flavors and aromas.