Juicy, oak & vanilla

Where flavour comes alive

March has arrived and with it, the promise of spring and longer days. The first shoots and flowers provide much needed comfort after the long darkness. Oaks in the glens shake off the rigours of winter in the warming breeze and tree sap flows back to the tips of the branches, awakening shyly greening buds. Since this month is a celebration of rebirth, trees and coconut-scented gorse, Julien Willems takes a good look at the whiskies in the Juicy, Oak & Vanilla flavour profile

The aromas and perceived flavours borne by these drams are a celebration of oak and more specifically what happens when American oak casks tip the flavour balance their way.

Think tropical coconut, oiled wood, honeysuckle, a pineapple sorbet, banana split and passion fruit and a nice chunky piece of millionaire’s shortbread… and that’s you, off to a spring picnic at the sawmill! For the flavour profile to boast a juicy side with a nice abundance of fruity flavours, you need the right spirit.

As with Sweet, Fruity & Mellow, esters play a key role in the fruity range of aromas we perceive in Juicy, Oak & Vanilla whiskies. These esters are created as by-product of fermentation and can create a wide variety of fruity impressions that are more or less perceptible depending on their concentration and interplay with other esters and flavour-active compounds.

This remains no less true for Juicy, Oak & Vanilla profiles, but here the fruity flavours may not always come through as distinctly when compared to Sweet, Fruity & Mellow whiskies.

To understand why that is, we need to look at the most important actor in creating Juicy, Oak & Vanilla whiskies: the cask.

A look at lactones

Oak can impart many aromatic layers to a whisky, and in this case, we can pin the dominant flavours on specific flavour compounds. Cis-oak lactones (lactones from here on), for one, provide the delightful aromas of gorse and coconut.

Lactones are naturally occurring ‘free compounds’ in most oaks but can vary in quantities and are particularly abundant in American oak (Quercus alba). European oak (Quercus robur) isn’t the first choice for this profile due to its tannic, spicy and gum-drying characteristics.

The reason for the flavourful bounty bestowed by American oak is at least partly genetic, intrinsically linked to the species, but we know there must be environmental factors – in other words, where these trees grow.

This is not fully understood, however. “Lactone concentration varies considerably from tree to tree of the same species, even in the same parcel of woodland,” explains the Society’s spirits educator Dr Andy Forrester.

This is when coopers come in. Their work is not simply the art of putting together a superb cask in a record time, it’s also about choosing, drying and seasoning the wood properly.

Some cooperages such as Seguin Moreau even go so far as testing every individual oak stave for lactone content prior to heat treatment – to discover high lactone casks produced at Seguin Moreau cooperage, try Batch #12 Clementine Confit or Cask No. 80.33: Advocaat snowball. However, as you may have guessed, it’s not just about lactone content.

Don’t discount European oak matured whiskies though, advises Dr Andy: “If the oak is from the right part of the continent, it can also be high in lactones. We know from research that oaks from Hungary, Croatia and Romania are rich in these sweet coconuty compounds.”

Check out SMWS small batch single malt Pomegranate Gremolata, which was matured in Caucasian oak… and expect more releases from these casks.

Feel the heat

The other dominant element in the Juicy, Oak & Vanilla profile is vanilla, or the molecule associated with that flavour: vanillin. This compound is not naturally present in oak, but lignin, its precursor, makes up most of the vegetal cell wall and therefore, most of the wood. To transform lignin into vanillin, oak needs to be heat-treated. Once exposed to flames and heat, lignin breaks down into a multitude of different flavour-active compounds, including a huge amount of vanillin. And this is again where coopers show that they’re not only skilled craftsmen, but they are also masters of wood chemistry.

They know the highly sought-after flavourful extractives lie in the ‘toasted wood’ immediately below the char layer in a bourbon (or charred oak) cask. “American coopers recognise the importance of creating flavour, that toasting is seen as just as important as the legally required charring,” says Dr Andy. “Huge amounts of research have gone into this in recent years – and experts like Kelvin Cooperage, to name but one, provide us casks they specifically toast to the right temperatures to create exactly the flavour profile distillers, or the SMWS, are looking for.”

It’s no surprise then that out of the 588 Juicy, Oak & Vanilla whiskies bottled by the Society since 2014, 93 per cent have matured in charred oak casks and 87 per cent have matured in bourbon casks. These casks are designed to impart a huge amount of flavour to the spirit they mature. Dr Andy explains: “US law dictates that bourbon must be matured in charred virgin oak barrels, meaning that they can only be used once. After only four years maximum maturing bourbon in its previous life, the wood is well ‘seasoned’, with the more intense woody character now mellowed but still has lots to give to the spirit. This makes the casks ideal for maturing Scotch whisky. The charring also ‘opens’ up the wood and increases spirit penetration, enhancing the maturation potential of the cask.”

Nature’s gifts

As a result, bourbon casks provide such intense oak-, vanilla- and coconut-laden flavours that it has the potential to overtake and mask the lighter fruity characteristics of a spirit, while complementing those fruity flavours that can withstand the woody influence.

Crack open the bottle of Juicy, Oak & Vanilla whisky closest to you, look out of your window and take a moment to celebrate the slow return of lighter, longer days and pay homage to the many delights of oak casks.

Or if, like me, you like to get a bit closer to nature, pour yourself a generous measure in your hipflask, lace your boots and head out to the hills to find a blossoming patch of gorse, a sunny hillside or a sheltered oak grove. Then with every sip, let that early spring elation free you from the chains of winter and remind you of the wonderous gifts nature has bestowed upon us.