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It’s Not Just About the Wood
July 23, 2017 | article | 10 minute read

President George W. Bush, it is claimed, once uttered, “The problem with the French is that they don’t have a word for entrepreneur.” Except he didn’t.

For as Churchill never quipped, “A lie gets halfway around the world before the truth has a chance to get its pants on”. The oft-quoted “80% of a whisky’s flavour comes from the cask” is a similar old chestnut. Rumours stick if they are surprising, easily quoted, and flatter an existing bias. This one’s been going for 20 years.

As with many so-called whisky facts it derived from a single source. Glenmorangie’s PR department. I believe it was from Bill Lumsden, their Head of Distilling & Whisky Creation, that I first heard a subtler promotion of this suggestion – though at 60% – in about 1998; I had sold them some surplus Madeira casks, as they were experimenting with finishing techniques at the time. Whisky writer Pip Hills certainly ran with it around that time, but cart, horse? Anyhow it now appears accepted as Gospel.



The marketing trick here, I suggest, is the creation of a narrative to account for the remedial action inflicted on a mature spirit suffering from old, over-used, exhausted, wood.

Unfortunately, the economic short-sightedness of the seventies and eighties, when single malts were destined to be a mere flavour component of blended whisky, meant casks were recycled excessively four, five, even six times. When single malts took off in the mid-eighties (Macallan, Glenfiddich, Glenlivet and a couple of others had been around for a while) distillers – or rather bottlers – were caught short: finishing, it’s euphemistically called, came to the rescue.

We’ve all seen the bottles: double, treble, quadruple wood; wine casks, quarter casks, chateau X, Y and Z. Qualitatively, it is a remedial action: how to reinvigorate a whisky that has languished in a cask where the wood is nigh on inert, having been stripped of its flavour elements by several previous occupying spirits. Done well it can be most effective; clumsily, and it’s a disaster.

At Bruichladdich we pioneered the use of French oak wine casks much to the amusement of fellow distillers. Now those critics are all doing it. Certainly, for us, the driving force for this laborious and expensive process was to improve, naturally, the uninspiring wood program of Invergordon days.

But the concept has proven to be an effective retail proposition by the marketing departments, aware they can use this method to increase their margins, listings and sales; and by swinging off the coat-tails of another famous brand printed on the label, gain reflected glory by association. Hence it’s gone crazy: wood, wood, wood, as each new bottling tries to out-wood the previous. Shame the industry didn’t think about it back in 1970.


Undoubtedly there are flavour compounds associated with oak, notably the tannins, lignins, and vanillins that are leached out by the spirit in a relatively short time frame. Depending on the oak’s freshness, origin, grain, genus, coopering etc., certainly these flavours will impact on the spirit and its flavours in varying intensities, and depending on the strength of the alcohol.

If one was to fill a cask with flavourless, neutral alcohol as close to 100% ABV as possible (illegal for whisky production incidentally) after a couple of months the resulting spirit would be brown, smell of caramel and taste tannic. It may look like a whisky, but it would not taste like it. That’s why it would be banned. You could try the same thing with plain water.

Indeed, nor would it taste of calvados, cognac, rum, or bourbon. This is because the identifying flavours of those spirits comes not from the ubiquitous oak casks, but from the primary ingredient from which the alcohol is derived.

Eau de vie, an excellent spirit derived from the distillation of fruits such as raspberry, cherries, plums, quince etc. has no contact with wood at all. Each spirit has it’s own character derived from the fruit from which it was distilled, each spirit deliciously discernible one from the other.

For single malt whiskies – and that’s all I’m interested about here – barley is the source of the extraordinary complexity of flavour that differentiates it from all other spirits. After all, the whole brown spirit world uses the same casks and they don’t taste the same! And barley is acknowledged as producing the most flavour compounds of any grain or fruit.

Quite how many flavours have been discovered in barley to date is hard to track down accurately. At the risk of starting another ‘rumour as fact’, I have heard over the last two decades of between 60 and 110 identified flavour compounds, mainly of the ester and aldehyde families, associated with barley. The mash extracts those flavours, others are added/converted during distillation.

What goes into the cask, flavour-wise, is crucial. For the oak, as well as being the source of the overt extractive flavour qualities mentioned above, is a mini maturing microcosm. Here the oak acts as a permeable membrane, a kind of osmotic Gore-tex, that allows alcohol and water molecules to pass out and oxygen in. Hence the flavour compounds, thus micro-oxygenated, are transformed over time into the flavours we associate with maturity. The cork on a great bottle of wine does the same thing.

But let’s turn it around. Suppose one takes three new make spirits distilled from, let’s say, grapes, cane, or barley and fill them in to the same type of casks. After three years would they really be identical? Or readily identifiable as cognac, rum and whisky? In fact why bother at all in buying a rum or a cognac or an Irish or a Scotch if they all taste the same thanks to the 80% claim?

The defence of this bizarre 80% claim is perhaps, on the one side, a sad reflection of industrial whisky production policy; and on the other, a blindness to the realities of multinational marketing, naivety at best. After all, in big operations the distillation side often has no idea what the bottling side gets up to, let alone the marketeers. But the reality is surely that if wood was really that impactful on flavour there would be no need for E150 or finishing…


Now the argument is: do the 100 or so flavour compounds of the new single malt spirit trump the flavour compounds of the oak? Well, if the oak is over-used and exhausted then clearly it does. Professional tasters will, like me, have tasted 20 year old single malts from such casks where the whisky is fully mature – but colourless. The oak flavours played no part.

Adding E150 will disguise this, as will changing the cask. Both are legal. The trouble with the former is it can be abused. And as for the latter the flavours of the new wood are often brashly out of synch with the micro-oxygenated mature spirit. It’s quite an art to get it right. Here perhaps the perception of these clumsily extracted wood flavours could be allowed to dominate the spirit.

But what about inert alcohol in new oak? Vodkas in oak do exist; I’ve tasted a couple, though I use the verb loosely. To find out the exact impact of oak alone we will need to fill a new oak cask with a neutral, flavourless alcohol to prove it. My guess would be that the flavours extracted would be crude and simplistic. But remember, that very crude brashness is precisely what is being sought by a bottler: a little goes a long way in remedial action. And there is plenty of research going on about how to short cut this process: oak essence, oak chips, extra staves, flavour injections, de-char/re-char, grating, ultrasound etc.



It’s semantics: to simply state that 80% of a whisky’s flavour comes from the cask is inaccurate and disingenuous. That’s not to say it is impossible – just that if it did, not many would want to drink it. On the other hand, to say a whisky’s flavour undergoes a complex evolution during maturation in cask – via interaction with oak and oxidation – is perhaps a little more accurate. After all that’s why we bother to mature it in the first place rather than drink it off the still.

Then you could say 100% of a whisky’s flavour is ameliorated by exposure to cask maturation.

Mark Reynier
Mark Reynier
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