Unopened bottle of St Germain
I recently discovered an unopened bottle of St Germain that was originally purchased at the tail end of 2008. It has been in a temperature-controlled environment for the past 4+ years. Is this still good for drinking? I have heard that unopened St Germain is only good for about two years, but am not sure if I buy that.
Otherwise, I am a cheap bastard, so I suppose the second part of that question would be if it's not still "good," is at the very least safe for a less discerning drinker?
For the most part, liqueurs don't spoil in the sense that you're thinking; it should still be safe to drink. However, over time, fruits and aromatics can oxidize and taste less good than they used to. If you've taken good care of the bottle, it may well still be as good as new. The first indicator is color; St. Germain should be pale gold. If it's a darker hue, it's obviously past its prime.
re: JK Grence the Cosmic Jester
I've had some older St. Germain bottles, and yes they do turn darker and cast a little sediment (brown particulate at the bottom), but they still retain floral notes, have that pear-like flavor, etc.
Originally, St. Germain claimed that the liqueur was good indefinitely. When people complained that it sedimented out, they put at first a 12 month and later 6 month declaration of when it should be finished by. Except for people who throw parties or drink a lot of St. Germain, this is not likely. I have had decent luck with 2+ year old bottles. Perhaps not as perfect as fresh, but it is not off like vermouth can get.