Do spirits "go bad"?
I always thought that liquor would survive a nuclear winter... but then I had a bottle of cassis that clearly "went bad."
We're currently debating whether an ancient bottle of cherry heering has gone off. How long can liqueurs live on the shelf (uncorked, but only very sporadically imbibed) and how does one know when they have gone off??
Somebody posted on another thread that over 40% (80 proof) would last forever. I don't know the science behind that but do know that things like vodka, scotch, etc. don't go bad. So maybe it IS the lower proof. I'm sure someone will weigh in with more accurate advice. I'll look forward to it cause I too have some ancient liquers.
I've committed the sin of allowing a bottle of fine whiskey to go bad. It does happen.
If you do not open the whiske and no air gets to it, then nothing should happen that detracts from it's taste. No spirit is going to age and improve in the bottle though either. Nothing should ever be able to grow in a spirit. Nothing pathoogenic can grow in beer (according to the "New Complete Joy of Home Brewing" by Charlie Papazian) because of the alcohol. Distilling that amount of alcohol and concentrating it is not going to make it easier for something to grow in it.
The bottlle that went bad on me (a fine bottle of Connemara) did so because of evaporation, I believe. The cork in it did not quite close tightly in the bottle. When I looked at the bottle after a number of months of not drinking from it (I was sampling occasionally from other bottles), the level of liquid was down from what I expected it to be. When I sampled the remains, it was slightly muddy and rather watery tasting. Alas, I lost some to the Angels' Share.
I've also had some corks get very dry and brittle in some of my bottles of whisky/whiskey, after which I had to work hard to deprieve the Angels.
Could a spirt go bad because of other things, maybe. But I am not aware of those ways.
I attended a few seminars hosted by Paul Pacult who writes The Spirits Journal (www.spiritjournal.com). I remember him saying something along the lines that you should consume the whole bottle within 2 months once opened. He has a very gifted sense of taste so I am sure most of us wouldn't notice any changes that quick.
Also, cream type liquors (Bailey's) should always be stored in the fridge. Same with Vermouth.
He repeats that recommendation here:
I can't say that I agree, and I'm thinking that if indeed he can taste differences after only a month, then perhaps having a gifted sense of taste is not so nice after all. To consume every bottle in my collection within two months would make me both very drunk and completely broke (if I were to attempt to replenish the stocks on such a regular basis)... I'll stick with not worrying about it!
Cassis isn't a 'spirit', it's a liqueur, and since many are relatively low alcohol they can go bad or oxidize.
Spirits can go 'bad' if the cork isn't a tight fit. Just in the past week I have had two bottles of really high end spirits that had been in storage for a few months that went bad. Both had corks/caps that weren't a tight fit. A small amount of the spirits had evaporated and the spirit turned cloudy and tasted lousy. One was a $80 David and McMurray rum, the other Laird's 100 proof bonded applejack.