The Milroy's Measure
Why are older whiskies so rare, anyway?
‘Old’ and ‘rare’ are two words commonly used together – especially when it comes to whisky. But why are older bottlings so hard to come by, and what’s age got to do with scarcity? Let’s unpack it.
We hear a lot about age in the whisky industry. Older is more expensive. Older is tastier. Older is better. While there certainly are a load of myths flying about (fact check: delicious whisky comes at every age statement!), there is truth to the sentiment that older bottlings are pretty rare indeed.
To understand why, it’s helpful to look at what age statements mean and how maturation works. That big number you see on a bottle? “10 Years Old”? “Aged for 15 years”? That’s the age statement – a guarantee of the minimum length of time the youngest component part of that whisky has been maturing in a cask for.
In many parts of the world – and certainly in the UK – whiskies must be aged for at least three years in a wooden cask to even be officially labelled as “whisky”. And that’s important. Because cask ageing will contribute an enormous amount of the aroma, flavour, texture and character of a whisky.
We hope our casks are watertight (no-one likes leaks, right?!). But they’re not airtight. And therein lies the magic. Casks can breathe – which means that they let in oxygen, allow evaporation, and in doing so, draw the spirit within into its wooden staves. How intense or otherwise that interaction is will be influenced by many things, from how new the wood is, the climate, and what (if anything) has been in that cask before. And, of course, how many years the whisky has been ageing for.
The angel’s share
We’ve already mentioned evaporation. During the maturation process, some of the spirit inside the cask will be lost into the atmosphere. In Scotland, this is usually around 2% a year, and this is called the angel’s share (a rather evocative idea – the angels getting their measure!). This annual percentage evaporation increases with warmth. For example, in Kentucky – where the evaporated portion is known as the devil’s cut – around 5% of maturing whiskey will be lost in a year. In India where the climate is much hotter, it can hit as much as 15%. Obviously, over time there will be less and less whisky left in the cask. Which is one reason why older whisky is much scarcer – it will literally vanish before your eyes.
- ~2% ScotlandLost each year to the angel’s share
- ~5% KentuckyKnown there as the devil’s cut
- Up to 15% IndiaWhere the climate is much hotter
Here’s the other thing – as the whisky evaporates, the ABV in the cask will usually drop. The legal minimum alcohol strength for whisky in the UK? 40% ABV. Casks often get filled with the spirit at 63% ABV. There’s some headroom, sure. But you’ve got to bottle that whisky before it drops below that.
Balancing the books
A far less romantic reason you don’t see older whisky: distilleries need to make money. Producing whisky is an expensive business. If you’ve got very tasty 10-year-old whisky, why wouldn’t you sell it? It’s already been a decade since you shelled out on the raw materials and the energy to craft the thing in the first place.
The balance sheet literally demands sales. If you can start making a return at 10 years, it can be challenging to hold whisky back for another three, four, or even five decades.
The flavour piece
Perhaps most importantly, there’s the character of the whisky and its flavour profile to consider. Over time, casks impart more and more flavour. Very few casks can actually hold whisky for 25-plus years without overwhelming it. Think about making a cup of tea – leave the bag in too long and it’ll get overstewed. No-one wants that when it comes to whisky.
That said, there is a very specific charm that comes with long-aged whiskies. That dusty, deep, savoury, forest-floor-and-furniture-polish note? It’s often referred to as ‘rancio’. And you only get it with long-aged spirits. There’s no way to hack it – and it can be so evocative, complex and downright mesmerising.
While older spirits aren’t better than younger ones, they are absolutely very different.
And when you get to taste something over, say, 25 years old? It is a special moment indeed.
There are so many reasons why it’s unusual to see whiskies aged into a third decade and beyond. Given the inherent challenges that come with maturation and the realities of business, it is a treat to taste long-aged expressions.
Auchentoshan 38 Year Old 1987
Looking to sample something extraordinary? Our Auchentoshan 38 Year Old 1987 just landed, bottled as part of our Vintage Reserve collection. It’s got the intricate lightness of a Lowland Scotch, aged for over three decades in a sherry cask. Scarce, rare, and very, very tasty – it’s the perfect place to start if you’re looking to explore long-aged Scotch.
