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Whisky aged in native oak  

Forget bourbon or Sherry casks. An increasing number of distillers are choosing to age their whiskies in barrels made from locally planted oak trees. Richard Woodard finds out more and recommends six great bottles to try. 

Whisky is emphatically a product of place. The flavours in the glass conjure images of the spirit’s origin, from an Islay malt’s distinctive peat smoke to the exotic perfume of a Japanese blend.

Traditionally, however, that local accent is lost when spirit is filled into cask. The vast majority of Scotch malts and blends, for example, are matured in oak sourced from thousands of miles away, and previously used to age bourbon or Sherry.

Some whiskies might venture into more exotic territory. Think rum casks, perhaps, or Madeira, Port or red wine. Fewer still are exploring the possibilities of native oak casks sourced from their own locale. But here the results, in terms of both provenance and flavour, are increasingly impressive.

Going local

So impressive, indeed, that Aberdeenshire distillery Fettercairn has planted 13,000 oak saplings on nearby Fasque Estate. The project is an effort to create a local and sustainable source of Scottish oak casks for the future. And we do mean the future – it might be 200 years before the fully mature oaks are ready for felling.

In the meantime, we have the newly released Fettercairn 18 Year Old (see below). This single malt is finished in Scottish oak casks, which are sourced from three sustainably managed forests in Ross-shire, Stirlingshire and Perthshire.

Beyond the back-story, what’s immediately impressive about the whisky itself is the full-on flavour. This is a richly spiced and structured whisky; the oak adding a fresh dimension to the distillery’s tropical fruit signature.

Close-up shot of a cross-section of oak wood

Different types of oak add their own signature to whisky

Scottish signature

Partly that’s the result of predominantly using ‘virgin’ casks – oak that hasn’t been softened by a previous maturation (as is the case with ex-bourbon or ex-Sherry wood). But it’s also clear, even at this early stage, that Scottish oak has a flavour identity all of its own.

So assertive is this character that Fettercairn master whisky maker, Gregg Glass, decided to ‘condition’ some of the casks with a pre-maturation of new make spirit for six months, just to tone it down a little. Glass is the driving force behind distillery owner Whyte & Mackay’s Scottish oak programme.

Glass’s approach won’t come as any surprise to Royal Salute master blender Sandy Hyslop, given his experience in creating Royal Salute 26 Year Old Kingdom Edition Scottish Oak Cask Finish. So concerned was Hyslop by the speed of maturation that he and his team were checking the casks every two weeks. The fear was, in Hyslop’s words, that the blend might become ‘too strong, too powerful, too dark’.

He explains: ‘After four months, it was beginning to freak me out a little bit. Are we going to have to sample it every week or it’s going to fall over? It was all about experimentation in the end – and fortunately this one absolutely worked out perfectly. But I’ve never seen a take-up of flavour like that.’

A man stands next to a large oak tree in a forest

Midleton uses Irish oak grown in Kylebeg Wood

Sustainability focus

As the example of the Fettercairn forest illustrates, these native oak projects are often as much about sustainability as flavour. It’s a recognition of the fact that Scotland – and indeed, the UK in general – simply doesn’t have the culture of managed forestry that has been in place in France since Napoleonic times.

As in Scotland, Ireland’s oak population has been exploited and decimated over the past millennium or more. Forests have been stripped for agriculture, ships and construction. The pendulum is now slowly swinging back as replanting occurs in places such as Kylebeg Wood in County Laois, boosted by the investment of private sector operators such as Irish Distillers.

Kylebeg is the backdrop for the latest chapter in the Midleton Dair Ghaelach project that began in 2009 (‘dair ghaelach’ means ‘Irish oak’). The Midleton Very Rare Kylebeg bottlings take provenance to a new level. This is a range of seven blended whiskeys, each matured in American oak for 13 to 25 years, then ‘finished’ for 15 months in Irish oak casks. Those casks are made using the wood of seven specific oak trees felled at Kylebeg.

‘Every bottling is traceable to a single tree,’ explains Midleton master distiller Kevin O’Gorman. And every tree plays a slightly different tune… Tree 7 combines plummy fruit with pot-still spice. While Tree 1 shows an elevated sweetness: black banana, caramel and crème brûlée.

‘There are subtle differences, tree to tree,’ says O’Gorman. ‘And you have to pick the right whiskey to go into these Irish oak barrels, because Irish oak matures quite fast and has lots of tannin. They’re heavy hitters… We’re definitely learning as we go.’

Two rows of whisky barrels in a cellar

Mizunara oak barrels at Yamazaki

Around the world

Ireland and Scotland are not the sole pioneers here. Japan’s distillers have long been exploring the fragrant, exotically spiced nature of their own mizunara oak (Quercus cispula). Meanwhile in the Pacific Northwest of the US, the Westland distillery is enhancing its own story of provenance, with a series of single malt whiskeys matured in locally sourced Quercus garryana oak.

At their best, these ventures do more than just create exciting new whiskies for drinkers to enjoy. The oak replanting programme at Kylebeg has lured pine martens back to the surrounding forest. And pine martens, it turns out, like eating grey squirrels, in turn allowing red squirrels to return. Trees, it appears – rather like whiskies – are powerful things.

Four bottles of whisky against a white background

Whiskies aged in native oak to try


Fettercairn 18 Year Old

Known for its tropical fruit character, Fettercairn is lured into darker, forest fruit territory by a finish in virgin Scottish oak. Wonderfully textured and punctuated with oak tannins and an array of spices – ginger, cinnamon, clove – plus a roasted arabica note. Alcohol 46.8%


Midleton Very Rare Dair Ghaelach Kylebeg Wood Tree 2

The seven bottlings in this series – each matured in casks that were coopered from a different tree – are all fascinating. But Tree 2 is my pick: mouthfilling and creamy, with an elevated, fragrant mix of spice, anis and white pepper. Hard to find, but worth seeking out. Alc 56.1%


Royal Salute 26 Year Old Kingdom Edition Scottish Oak Cask Finish

A muscly, structured Salute blend that marries fleshy berry fruits with darker scents of treacle and molasses. With a whisper of smoke from Caperdonich peated malt – and from the Scottish oak – this is densely packed, but lifted by Longmorn’s juicy fruit. Alc 40%


The GlenAllachie 15 Year Old Scottish Virgin Oak

Another Scottish oak ‘finish’, this is a ripe and satisfying dram, with stewed plums and candied orange peel alongside dark honey and black banana. There’s also zesty citrus fruit and butterscotch mingling with treacle toffee and white chocolate notes. Alc 48%


Westland Single Malt Garryana 5th Edition

This single malt from Washington State has the highest proportion yet of whiskey matured in locally sourced Quercus garryana (aka Garry oak) casks. Sawmill aromas vie with zesty lemon, caraway, cinnamon and feral smoke from some peated spirit. Alc 50%


Yamazaki Distiller’s Reserve

A vatting of Bordeaux wine, Sherry and mizunara casks makes for an über-fruity whisky, full of ripe strawberry and white chocolate. Mizunara oak brings a lovely fragrance – dried flowers and sandalwood – and it’s a lot more affordable than a fully mizunara-matured Yamazaki 18. Alc 43%


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