I have been told that one of the benefits of whisky is that it is supposed to keep very well once opened, and many of my friends and simple (perhaps not directly whisky related) online forums seem to suggest this. However, I was interested to explore this after some of my own observations.
I recently had another go at a bottle of mine (century reserve lot 15-25), and noticed it wasn’t quite what I had remembered. I had noticed before with peaty scotch that the peat diminishes over time as the bottle remains open, but I wasn’t sure how things would go with rye and bourbon. As Century Reserve Lot 15-25 is a good quality and relatively cheap whisky I decided to purchase a new bottle and compare how the new bottle was to the old one.
I had bought the old bottle roughly one year ago, and had kept it open (although I had used wine preserver gas to try to keep it fresh). You can see the level at which it was kept below, where the old bottle, with a lower level of whisky, is shown beside the newer bottle with more whisky in it.I conducted three blind tastings, with the two whiskies for comparison. Whiskies do vary from batch to batch, although most blends are made in such a way that the tasters cannot tell the difference between the old batch and the new one. Thus, I am assuming that the batches started with more or less the same flavour. Additionally, this is just one case for one whisky, and the results of this experiment may not be representative of all whiskies. However, it seems to confirm some of my hunches….
The link to my review of this whisky is here, and this describes the tasting notes of the newer (i.e. recently opened) bottling that I purchased.
The whiskies, of course, were very similar, but there were noticeable differences. Even at the first tasting I guessed correctly which was from the recently opened bottle and which was from the bottle that had sat opened for some time. At the two subsequent blind tastings, I also found that I could easily pick apart the “new” bottle from the “old”.
Here are differences, along with how I rated each of the whiskies so that a reference is put in place for a quantification of the effect of the air in the open bottle. For the sake of simplicity I will call the whisky from the newly opened bottle the “new” whisky, and the whisky from the old bottle the “open” whisky.
Nose: The open whisky is more fruit-forward, with more sour notes and the rye seems duller.
For the new whisky, the nose is sharper – there are sharper distinctions between the different parts of the nose, and the vanilla develops more prominently as the whisky sits. The rye is sharper, and features more prominently in the nose. It seems as if it is just a much clearer expression of what this whisky is trying to do. It’s a bit creamier, too.
open whisky score: 25.5/30 (85%)
new whisky score: 26.5/30 (88%)
Taste: The taste between the two was quite similar, but the mouthfeel, surprisingly enough, was different. The new whisky was thicker, and more mouth-filling. The rye in the new whisky was sharper, the taste was less sour, and the spice more firmly held its ground.
open whisky score: 25.5/30 (85%)
new whisky score: 26/30 (87%)
Finish: The finish was more clear cut in the new bottle, lasted longer, and was less bitter. From the open bottle, I found the rye flavour developed to a climax 6 seconds after I had swallowed it, and lasted for a good 40 seconds before it started to fade and become a touch bitter. For the new bottle, I found the climax of rye flavour occurred at 9 seconds and was still rye and spice heavy 30 seconds in, and didn’t fade until over a minute after I swallowed. The peaks were more prominent, more clearly defined, and the experience was longer for the new whisky.
open whisky score: 13/15 (87%)
new whisky score: 13.5/15 (90%)
Conclusion: I could tell which was which because I recognized the aging in a similar way as I would in wine – the oxygen from the open bottles appears to bring the fruit a bit more forward, dull out the edges of the whisky, and mellow it out a little. Unfortunately, the extra air in the open bottle appeared to accentuate the worse parts of this whisky for me and dampen the good bits. Upon each of my three blind tastings the results were quite similar.
open whisky conclusion score + overall score: 16.5/20 (83%); 85/100
new whisky conclusion score + overall score: 17.5/20 (88%); 88/100
As seen, in this case, it affected my own overall score by 3 percentage points. I could see how, perhaps with some whiskies, this extra exposure to oxygen may even be a bit of an advantage. However, my advice would be to try to limit the number of open bottles you have, where possible. Perhaps nursing a very special bottle over months or even years (there are probably some of you out there!) is not as good a strategy as just having one extraordinary whisky month or two. There’s some balance between this and having different open bottles for you and your friends to sample from together. Once I have a bottle dipping below the halfway mark, I think it’s good to concentrate on enjoying that before the oxygen takes too much away.
On a somewhat-related note, on the topic of storing whisky, if you are interested in knowing more, I recommend this link (from the entertaining Ralfy).