As an expert sommelier and brewer, I can confidently say that whiskey can indeed go bad if stored in a glass decanter for an extended period of time. While whiskey does not oxidize as quickly as wine, it is still susceptible to changes in flavor and quality over time.
When whiskey is exposed to air, it can undergo a process known as oxidation, which can alter its taste and aroma. This is why many whiskey enthusiasts prefer to store their bottles in airtight containers, such as the original bottle or a tightly sealed decanter, to minimize contact with oxygen.
However, even when stored in a decanter, whiskey is not completely immune to changes. The longer it sits in the decanter, the more likely it is to experience some degradation in flavor and intensity. This is particularly true for delicate and nuanced whiskeys, where any subtle nuances can be easily lost.
One of the main factors that can contribute to the deterioration of whiskey in a decanter is the exposure to light. Direct sunlight or even prolonged exposure to artificial light can cause the whiskey to degrade more quickly, leading to a loss of flavor and potential discoloration. Therefore, it is important to keep your decanter in a cool, dark place to minimize these effects.
Another consideration is the quality of the decanter itself. If the decanter is not made from high-quality, non-reactive glass, it may interact with the whiskey and affect its flavor. Cheaper decanters may contain lead or other chemicals that can leach into the whiskey over time, altering its taste and potentially posing health risks.
Furthermore, if a decanter is not properly cleaned and dried before storing whiskey, it can introduce unwanted flavors and aromas into the spirit. Residual soap or moisture can contaminate the whiskey and lead to off-flavors. Therefore, it is crucial to thoroughly clean and dry the decanter before transferring whiskey into it.
In my personal experience, I have noticed that whiskey stored in a decanter for an extended period of time tends to lose some of its initial vibrancy and complexity. The flavors can become muted, and the overall drinking experience may not be as enjoyable compared to a freshly opened bottle. I have also observed slight discoloration in some cases, particularly with whiskeys that have a higher concentration of natural colorants.
To summarize, while whiskey can last for a considerable amount of time in a glass decanter, it is best to consume it within a reasonable timeframe to fully enjoy its flavors and aromas. Prolonged storage can lead to discoloration and a loss of flavor intensity. Therefore, it is advisable to keep an eye on the duration of storage and consider finishing the decanted whiskey within a year or so to ensure optimal taste.