It’ll never go bad unopened. What will happen is angel share (evaporation) slowly over time. Will result in a weaker proof but more flavorful. This is like 100 years I’m talking. If yoj mean for a couple months or years, it will taste the same regardless of when you open it. All the flavor maturation was done in the cask. Once bottled there’s no active yeast or anything or agent to affect taste.it gets no better or worse.Yummm... View attachment 21618