WHISKY KNOWLEDGE
Cask variety
There are plenty of things that make The Scotch Malt Whisky Society’s single malt bottlings special – their individuality, their variety and of course their rarity. It’s no secret that lots of the magic takes place during the spirit’s maturation, but it might come as a surprise just how many strings the Society’s Whisky Team have to their bow, as Duncan Gorman reports
PHOTOS: PETER SANDGROUND AND MIKE WILKINSON
There’s always been a big debate over how much influence a cask has over a whisky’s final flavour. At the Society we’re most passionate about single cask whisky, meaning that a cask’s influence over the whisky changes from bottle to bottle because each one is entirely unique. There is however one thing we can be certain of – that there is an infinite number of flavours waiting to be discovered. In the past year alone, the Society bottled over 160 different spirits and used around 100 different wood types.
QUALITY AND VARIETY
Bourbon casks are in some respect the workhorses of the Scotch whisky industry, and are renowned for offering a sweet, honey and vanilla character to the whisky. Alongside the notes of coconut from the high lactone count found in American oak, these casks can make for a very approachable dram. In recent years sherry casks have also rocketed in popularity, whether it’s the well-balanced nuttiness from oloroso, or the decadent dark fruits from Pedro Ximenez (PX).
First fill sherry casks are known for having a large influence on the whisky over a relatively short period of time and are often used during periods of additional maturation (a process where the spirit is moved from its initial cask to a new cask for further aging of two years minimum) here at the Society.
The Scotch Malt Whisky Society thrives in sourcing a diverse variety of casks as cask operation planner, Ed Furmston-Evans, says: “We have an established approach to experimenting and expanding the range of cask types in our inventory, based on evaluating the impact that different casks have on different spirits, which allows us to match the best casks to let our whisky really shine,” he says. “There are two main objectives to our cask selection process – we aim to deliver the best possible quality and a high level of variety. By proactively engaging with our wide variety of suppliers, visiting wineries and cooperages, we are able to ensure we get the best quality casks available, and also hear about novel casks that we can share with our members.”
ABOVE: The SMWS thrives on sourcing a huge variety of cask types
PICTURED: A fresh load of casks is delivered to the SMWS warehouse
FREEDOM TO EXPERIMENT
Over the years our Whisky Team have been responsible for more than a few unique bottlings, letting their imaginations run wild, as Society whisky and Tasting Panel coordinator Julien Willems elaborates: “I would say that a great example of unique casks and experimentation by the Society has been the hybrid cask series made up of both European and American oak. It included gems like Cask No. 64.138: Perfect for tannin’. We’ve also been working with casks where each stave had been handpicked at cooperages for its high lactone content, which is associated with coconut aromas, giving us a somewhat bonkers Cask No. 80.33: An Advocaat snowball.”
There are a huge number of parameters that can change the way a cask interacts with its spirit. The easiest one to spot is usually whatever the cask has been used to hold beforehand.
ABOVE: SMWS whisky and Tasting Panel coordinator Julien Willems
Casks that have previously held rum offer a tropical twist over the spirit, creating flavours like exotic fruits or molasses. Meanwhile in a similar fashion to sherry, port casks offer hints of ripe fruit, spice and subtle sweetness. The Society has even experimented with the use of stout beer barrels, although we’re still waiting patiently to get a taste of the finished article.
Julien adds: “Recently, we have also seen a number of rarer wine casks such as cosecha wine casks from a bodega that only uses PX grapes, no matter the style of wine they produce, with bottlings such as Cask No. 1.286: The finesse and energy of a hummingbird, and since we are on the topic of bodegas, we’ve had a number of actual bodega sherry casks, or things that are unchartered territory such as French oak Jamaican rum that gave our members new flavours to explore in Batch 20: Whisky Baba or Cask No. 6.66: The Devil’s call.”
However, our Whisky Team need to be careful not to push the limits too far, with the Scotch Whisky Association (SWA) enforcing strict maturation laws. Casks that have been used to hold fermented liquid, or that’s been distilled from stone fruits, are off limits. Sometimes even using the correct cask type isn’t enough to pass requirements, with the clause stating: “Regardless of the type of cask used, the resulting product must have the traditional colour, taste and aroma characteristics of Scotch whisky.”
This is an addition Julien has come close to, as he explains: “One of the challenges we sometimes encounter are casks that conform with SWA requirements but yield unexpected results. Think of Cask No. 48.104: Punnets of pink, which was maybe a bit too pink for its own good!”
PICTURED: Toasting or charring the cask’s staves for different times can dramatically change how the spirit interacts with the wood
LIMITLESS PARAMETERS
It’s also worth noting that a cask’s impact over a whisky will fade after time, and this is why most casks are categorised as being ‘first fill’, ‘second fill’ or ‘re-fill’. As you can imagine this refers to how many times the cask has been used to mature whisky, with ‘re-fill’ covering any cask that has been used more than twice. However, these terms can only be used as a loose guide, as not every cask’s history is known, so it can be impossible to know how long they’ve been used for.
You might also have heard our Whisky Team discussing a cask’s toast or char level, which again can completely alter how spirit interacts with wood. Although it may sound a bit bizarre, this really is as simple as it sounds. A cask is toasted by flaming it at around 290°C, while charring is at a higher temperature of around 315°C. Toasting or charring the cask’s staves for different times will offer various levels of influence, but generally this enables compounds like vanillin and eugenol in the wood to bring out more flavour in the whisky. Heat treatment also makes it easier for the spirit to penetrate the staves, again making it easier to extract these compounds. It’s also quite common for used casks to be given an ‘STR’ treatment where they are shaved, toasted and re-charred, which helps make wine barriques quality vessels for whisky maturation.
ABOVE: Wine casks such as amarone in the SMWS warehouse
These are just a few of the almost limitless number of parameters used to influence the impact of each individual cask. By experimenting with a range of various spirits, wood types, toasts, chars and additional maturations, each cask released by the Society is a unique fingerprint never to be repeated again.
Julien finishes by saying: “In the last year alone, we have bottled over 160 different spirits coming in just about 100 different wood types, and this is not even taking into account the number of fills of these casks. So the number of permutations you could imagine – and the ones we’ve already produced – are just eye-watering.
“We are always searching, discovering, experimenting, sometimes following traditional guidelines, sometimes going against the grain, all for the sake of variety, flavour exploration and discoveries.
Our mandate is to create the widest possible variety of quality drams, faithful to the idea that there is a whisky for everyone. So, in a nutshell, the ‘usual’ you can look forward to is our inherent unusually wide expansion of the flavour horizons we strive to create for our members.”