Production

Return and burn

Neil Ridley visits Diageo's main cooperage to find out how cask life is being extended
By Neil Ridley
Last Year, Diageo introduced its£10 million super cooperage at Cambus in Clackmannanshire, redefining the future of this traditional, and historically artisanal business. But what does the cooperage mean to the legacy of a cask?

On my first visit to Cambus, I must confess to feeling slightly apprehensive about what I was about to experience. Coopering is perhaps one of the most essential elements within the process of maturing whisky – and comes hand in hand with decades of tried-and-tested craftsmanship, each cask a living, breathing vessel, which the cooper has painstakingly (and skillfully) bought to life. I wondered whether the influence of the 21st century and the greater emphasis that whisky companies place on efficiency would somehow jeopardise the legacy of the cooper as an artisan; machines replacing highly skilled individuals, whose human touch is individually etched into each and every stave they shape.

I was, of course, way off the mark. As I experienced first hand (in issue 99), coopering is now a thriving business, with the appointment of Cambus’ new apprentices and a rigorous training scheme demonstrating Diageo’s commitment to maintaining tradition alongside a modernist approach to meeting the increasing demands for whisky across the globe. But what was also abundantly clear was the greater emphasis placed on extending the life of the seven million-plus casks that Diageo currently own.

“Casks could be around for 150 years old before they become redundant”


When it comes to wood management, the Cambus cooperage has five different areas of expertise: rejuvenation, repairs, enlargement and a two-stage process of rebuilding casks, using different types of stave.

For Alan Hadden, Cambus cooperage project delivery manager for Diageo, the cooperage’s most interesting aspect focuses on bringing casks back to life through rejuvenating them. Cambus is expected to produce around 250,000 rejuvenated and rebuilt casks a year, which poses quite a challenge for the new facility.

“In 2009, Diageo had two cooperages, which together produced approximately 200,000 casks per annum,” he explains. “The challenge we faced was the requirement to increase cask production by around 25 per cent and unfortunately, the existing facilities were not suitable for expansion.”

For Hadden and his team, consolidating all the coopering facilities under the roof of one purpose built, automated site has meant that not only have the more physical and inherently dangerous aspects of the coopering trade been made safer and more efficient for those involved, but the transport operation of physically moving casks around from site to site has been reduced by around 7,000 vehicle movements per year.


The Resurrection


So how does the rejuvenation process take place at Cambus?

Casks at the end of their current usable life (usually after the 5th fill) are initially broken down and stripped of their ends and quarter hoops, to be reunited with them later at the end of the automated production line, using an ingenious RF (radio frequency) tagging system that keeps the removed parts in perfect syncronisation with the cask on the conveyor belt. The first process of de-charring is done via a machine using a unique circular ‘shaving’ process, which takes the cask insides back by around 3-4mm, removing the undesirable elements of the used wood and exposing a layer of fresher, newer wood. Traditionally a crude flailing system removed the spent char, but the new system gives an optimal level of consistency to each cask.

At the next automated stage, Cambus employs robotic technology to lift the de-charred casks into heating chambers, where they receive three minutes of re-charring, toasting the fresh wood. They are then re-hooped and have their existing ends fitted.

From start to finish, the whole process takes ten minutes, which means that around 500 casks can be processed per shift, with two shifts a day each employing 16 fully trained coopers.

Diageo’s laboratories closely monitor samples of spirit taken from casks nearing the rejuvenation process by using a specialised tint meter, to measure the colour of the whisky, which will ultimately determine how much life a cask has left in it. James Carson is one of the men tasked with effectively deciding the fate of a tired cask. “With our current rejuvenation process we’ve really extended the life of our existing casks,” he explains. “It’s possible that casks could be around 150 years old before they become redundant, which highlights some additional sustainability benefits.”

Sampling a whisky matured in a rejuvenated cask, next to one from the stage before is enlightening and certainly goes some way to explain why the cooperage has placed such a huge emphasis on the process.

Whereas the spirit from a 5th fill ex-American Bourbon cask is pale, spirity and lacking much in the way of direct character or aroma, the rejuvenated cask imparts a surprisingly pronounced woody, spicy character to the spirit, alongside additional notes of rich vanilla and clove. “Our future blended whiskies will use a proportion of rejuvenated wood,” points out Carson.

Some critics will no doubt argue the merits of extending the life of a used cask in the production of a consistent blended whisky.

But when you take a second to consider the spiraling costs of purchasing quality fresh Bourbon casks, coupled with a mounting pressure on storage facilities, the Cambus cooperage has certainly set the benchmark in helping to create a more efficient, cost effective and ultimately sustainable whisky business.