Can your 10-year-old bottle be considered a 20-year-old whisky if it’s been sitting unopened in your bar for a decade?

When it comes to whisky, age is the essence. You may have seen (pop culture) savants Don Draper from Mad Men or Harvey Specter from Suits pulling out a 20-year-old bottle of scotch for special occasions, because, in most cases, older whiskies taste better than the younger variants. This is due to three main factors: aged whiskies have a more unique and complex flavour profile, a full-bodied flavour and a longer finish.

Going by this logic, an 18-year-old whisky is far more preferable than a 3-year-old bottle. However, there’s been widespread confusion about the factors that determine the age of a whisky — and more importantly, whether the usquebaugh continues to age once it's bottled. For instance, what if you come across a 15-year-old bottle of Glen from your grandfather’s prized collection? Since it’s been 20 years since he purchased it, does that mean that the whisky is now 35-years-old? Here’s what you need to know.

Does whisky age in the bottle? Here’s everything you need to know

What is the ageing process? Before delving into the pertinent question on whether whisky ages in a bottle, let’s first understand how the whole process works. It all starts when the spirit is maturing in the oak casks. The longer the whisky spends in the cask, the more flavour it will impart from the wood that it matures in. Various categories of the golden elixir have distinct requirements for this method. For instance, scotch whisky has to be matured for a minimum of three years (and a day) to be legally classified as scotch, while American bourbon must be aged for a minimum of two years in fresh charred oak barrels.

Temperature of the surrounding environment also plays a crucial role in the ageing process. If the cask is kept in a warmer climate, the whisky will mature much faster than one placed in a cooler climes.

Does whisky age once it's bottled?

Once whisky is poured into a bottle, it stops ageing. The usquebaugh gets its flavour from the barrel it is matured in. This is because the spirit penetrates the wood fibres, breaks down compounds like wood sugars, and then pulls them out of the wood and into the whiskey. Simply put, it’s the interaction between the whisky and wood that enhances the entire ageing process. Once the whisky is poured into a bottle, the ageing process stops immediately.

So that bottle of Glen from your grandfather’s collection isn’t 45-year-old whisky. If it’s unopened, it’s still a 15-year-old scotch and will taste exactly as a 15-year-old scotch would.

It would only reflect changes in flavour depending on its oxygen exposure, light exposure, and temperature fluctuations.

[via GQ India]