As we begin to approach Spring, for many people that means dustinga round the home bar and pulling out that bottle of Scotch someone bought you last year. So the question naturally arises, “can I drink it or has it gone off?” To be fair, at all times of year the question of how long whisky will last in its bottle is among the most common I receive. The Spring Cleaning season just makes the answer more relevant to more folks, so today I will try to answer it for you.
We must begin by discussing the case of the closed, sealed, un-opened bottle. First of all, this should never have happened. When someone gifts you a whisky, it is etiquette to open the bottle and offer the giver, guests, and of course yourself, a drop of the amber nectar. It shows appreciation and is common courtesy, in my experience in Scotland and beyond. This is the tradition. And if it is not “the tradition,” then I, as a whisky giver, am determined to make it one!
But if, for whatever reason, the bottle has remained sealed, you can rest easy in knowing that it should last indefinitely and never ‘go off”. This is why many whisky lovers (myself included) have more than one, ten, or twenty open bottles on their shelves. Variety is the spice of whisky life and because they all taste different, it is often worth having a variety on hand to ensure we have a dram to suit our given mood.
Now, depending on the quality of the seal (not all screwcaps or corks are created equal) variable amounts of evaporation may take place, but this takes decades, not years. This is why some collectors and auctioneers will speak of ‘fill-levels’, referring to how far up (or down) the bottle neck the liquid sits. That being said, the effect on the taste of the spirit is negligible. However, it is also worth noting that in my experience whiskies opened 40 or 50 years after their filling dates will deteriorate quicker than more recently filled bottles… which brings us to the next naturally question: once opened, how long will my whisky last?
The short answer is that whisky will never “go bad”, but that does not mean that it’s chemical make-up and flavour(aroma and taste) will not change. Once opened, whisky (ethanol) is being actively exposed to air (oxygen) and thus, oxidation begins to occur. With wine, port, or wine-based spirits, this process can be desirable for short periods of time, and the same can be said for whisky. But if we assume that we will open our bottle of whisky 30 times before it is empty we are allowing new oxygen into the bottle 30 times. Naturally, the spirit will start to change by evaporation and by this exposure to air, but again, this change will be largely unnoticeable. However, should these 30 openings take place over, say, 30 years, then we have something to worry about.
As a general rule, my advice would be to drink your bottle at a comfortable pace. However, once the ‘headspace’, the amount of empty space (where the air is), in the bottle is larger than the full space (where the whisky is), changes might begin to become noticeable.
SO you have a few options. Many people recommend decanting the whisky in to a vessel with less headspace, ie. a smaller bottle. This makes sense, I suppose, but if you have more than one bottle this can create a mess of miniatures all over the kitchen, living room, etc. Instead, Dr. Whisky’s advice is to finish the darn thing. You can do this alone, but no one should drink alone. Whisky is a communal spirit. So, call a few mates, tell them “I have something really important I need to discuss with you,” invite them over, and finish the bugger.
Then go buy another.