Ever been at a whisky festival, seeing someone shaking the bottle saying "I am checking if it really has higher alcohol strength as the label says"...Yes it did happened to us. But as it turns out, it is not that strange approach after all. Our whiskipedia Brendan Pillai is here to confirm the theory behind this phenomena.
Enjoy his short article for better understanding.
" Whisky is known for having a multitude of aromas and flavours, but sometimes the former can be rather muted when you're nosing directly from the bottle. This could be due to a number of reasons including the whisky needing time to aerate in order to fully open up and showcase its depth. But would there be a shortcut that one could resort to instead of pouring out a dram (which is also a fantastic option as one would then be able to taste it)?
The easiest way to do so, while not guaranteed, would be to give the bottle a shake before opening it and nosing it.
This is a common occurrence at whisky shows as some higher strength whiskies tend to be closed off in the bottle and therefore not be as aromatic initially, so patrons and exhibitors alike will sometimes shake the bottles vigorously in order to agitate the whisky within and allow for the aromas to manifest.
Shaking the bottles for higher strength whiskies which have not been chill-filtered would also allow for the congeners within to be activated and these would then provide patrons with a better nosing experience, although it still would not be as prominent as when compared to nosing it from a dram glass.
Shaking the bottle is also another method (albeit not a foolproof one) of checking if the spirit within is of a higher or lower strength. The general consensus would be that the bubble that form after shaking would take longer to dissipate if the spirit is of a higher strength and also tends to dissipate much faster if the spirit was bottled at 40% ABV due to the lower amount of congeners and lipids within.
While it is an inexact science, shaking a bottle of whisky does have some benefits and it provides a glimpse into the true nature of a whisky.
That being said, nothing beats a good measure in a dram glass!"
...No matter how long you are in the business, you always learn.