News of Glenfiddich’s new “Rich Oak” whisky raised some eyebrows in the Esquire office: this single-malt is – deep breath – finished in virgin oak barrels. In terms of the Scotch industry, this is nothing short of a revolution.
Traditionally, single-malts are matured in the barrels that have previously been used to age spirits such as bourbon – the benefits of which are three-fold: firstly, bourbon has to be matured in new oak by law, so it is cost-effective to re-use casks in this way; secondly, the bourbon absorbs some of the wood’s tannins, extracting the less subtle flavours from the oak; lastly, the bourbon soaks into the wood, adding depth to the Scotch’s flavour when it is later added to the used barrels.
So why should a single-malt Scotch want to use virgin barrels? We asked Glenfiddich malt master Brian Kinsman to explain.
ESQUIRE: So we thought that Scotch whisky was always matured in old oak casks. Is this not the case? Are there any laws about what you can/can't use?
BRIAN KINSMAN: Yes, the Scotch Whisky Laws state that the whisky must be matured in oak casks of a capacity not exceeding 700 litres for a minimum of three years. The traditional sources of casks for maturing Scotch whisky are the American bourbon industry, Spanish sherry industry and also various other smaller sources such as port, madeira, wine, rum, etc.
ESQ: What inspired the decision to try new oak?
BK: As a pioneering company we are always looking for innovative new products. Working directly with our own coopers and cooperages in the USA and Spain we developed casks that would bring the favours we desired to the finished Glenfiddich Single Malt.
ESQ: Tell us about the barrels: where are they from, and how long/how were they seasoned before you used them?
BK: Our own coopers travelled to cooperages in Kentucky and Jerez to oversee the production of the casks. The key for the flavour in this particular whisky is that the casks have held nothing before and have not been seasoned with any other spirit or wine. The American oak casks are toasted and charred in the same way as they would be for filling with bourbon but sent to us directly with no bourbon filling. The Spanish oak casks are only gently toasted and not charred, this maximises the rich oaky flavour.
ESQ: How long does the "finishing" process take?
BK: Because the casks are virgin oak the finishing period is very quick. The 14-year-old Glenfiddich is already well matured and sweet therefore filling into new oak casks means the whisky starts to pick up intense oak flavours immediately. It is important to sample the casks every couple of weeks to ensure the oak doesn’t overpower the final flavour balance. Typically the finish is between six and 12 weeks with the Spanish oak being quicker.
ESQ: And what characteristics does this new wood give the whisky that you wouldn't normally find?
BK: The Spanish oak gives rich, deep flavours with nutty, dried fruit and oak. It adds texture and “mouthfeel”. The American oak adds lighter, sweet, vanilla character with fresh fruit and toffee. When they are combined together the result is a balance of sweet, vanilla fresh fruit and rich oak notes with a beautiful silky mouthfeel.
Rich Oak, £30 at Sainsburys, www.sainsburys.co.uk