The largest bill for any whisky distiller is the wood. At least, it should be.
Usually the cask bill is the first budget to be slashed, it’s the easiest to cut. Millions are tied up in an inert container – the accountant thinks – so why not recycle? Buy cheaper? Cut corners?
It’s a false economy: any compromise on wood is a compromise on whisky.
A cask is not only a convenient container but a microcosm surrounding the new spirit. The fresher the oak, the thicker the staves, the more wood flavour compounds there are to add to the spirit; conversely, the more tired and over-used a cask is, the more banal it becomes.
The first spirit to enter a virgin cask will quickly absorb flavours; a quick wham bam as the wood’s flavour compounds of lignin, vanillin and tannin are rapidly extracted via the alcohol – the higher the strength, the quicker and greater the effect. These supplementary flavours are added on top of the spirit’s own barley-derived flavours. This can be clumsy or it can be subtle depending on the wood policy in place.
The standard industry procedure is to re-use casks once they have been emptied of their mature spirit at bottling. This in itself is a wise use of an asset, assuming the wood has not been flogged to death, and still has life.
A second filling of new spirit and there will be substantially less for the alcohol to extract. Unless, that is, the strength is higher than the previous alcohol, in which case some extracts will be obtained.
A third usage and there is very little for the wood to give; the oak is then more or less a passenger – it might as well be plastic if it wasn’t for the much more important micro-oxygenation of the spirit’s intrinsic flavours constantly occurring via the oak’s pores.
Some commentators even claim that ’70% of a whisky’s flavour is derived from the cask’. If that was genuinely the case producers would bypass expensive distillation altogether and simply add water to oak shavings! Why bother using barley, the most flavoursome grain? Certainly the amelioration of a spirit’s flavour compounds by micro-oxygenation occurs thanks to porous wood. While the supplementary ‘icing on the cake’ flavours – both tannins and cask-contents – can play their part, it should never be so clumsy as to dominate the spirit’s own flavours.
To replace a comprehensive wood policy, to save money, casks can be manipulated: heat, music, vibration – even ultrasound – can save maturation time. Others believe that oak essence, caramel, wood chips or tannin injections will speed things along. But there is no honest short cut. Oak is too vitally important to the maturation of whisky.