Sherry cask masters

Fruit cake, toffee, chocolate, nuts...sherry casks can contribute distinctive characteristics to their whiskies, to the extent that the label “sherried whisky” is a style in its own right.

Some distilleries – such as The Macallan – use sherry casks exclusively across their range. Others do special expressions, for example Glenmorangie Fino Sherry Wood Finish, Talisker Amoroso and Laphroaig PX, to choose a few.

So there are elements both of tradition as well as experimentation when it comes to the use of sherry casks. BenRiach master blender Billy Walker, for example, took on that tradition when he acquired GlenDronach distillery, which has always focussed on ageing its spirit in sherry casks.

“From the historical richness of the whisky’s colour there was clearly a significant contribution from Pedro Ximenez sherry casks,” says Billy. “So when we inherited the distillery, we began the process of re-racking casks that had been filled into bourbon casks into the right balance of PX and oloroso sherry casks.” Billy says the heavier PX sherry gives the whisky a sweeter, richer finish. He has experimented with the lighter fino sherry and other varieties, but says the “traditional” characteristics he wants comes from a mixture of PX along with oloroso casks.

Both The Macallan and Highland Park use dry oloroso exclusively, to give their whisky an amber colour and spicy, dried fruit notes, although Edrington’s master of wood, Stuart MacPherson, says the barrel itself is still a more important factor than the sherry. Edrington uses oak from both Spain and the US for the casks it prepares in Jerez.

“Around 60 per cent of the final character and aromas come from the wood,” he says. “From European oak the levels of cask extractives, including vanillin, eugenol and tannins, are higher, giving more sweet, woody and spicy characteristics. In American barrels the levels of oak lactones are higher, which contribute more coconut and fresh fruit.

“Oloroso sherry casks seem to work well with the Macallan spirit. It may also be that we used to get oloroso shipped to Scotland in casks, which is not likely to have happened with fino sherries – my understanding is that the layer of flor on the top of a fino would have been disturbed during transit.”

With Bunnahabhain, Burn Stewart master blender Ian MacMillan also inherited a 12-year old oloroso-influenced whisky. His innovation was to do away with the chill-filtration process, which he says has allowed more of the sherry flavours and influences to come through in the final product.

He has also experimented with different types of sherries, including fino, amontillado, manzanilla and PX, but he prefers oloroso for its balance. “Oloroso is not overly sweet, it’s a medium sherry, it has a nice rich flavour and it balances out well,” he says. “You never want the sherry to be too prominent right at the front where it might disguise the whisky. Sherry should always be a backing singer, it should never be a lead vocalist.”

Ian makes regular visits to Jerez where he deals with different bodegas to source barrels for Bunnahabhain. He says that in the past, sherry casks were in greater supply, but as the whisky market for sherry wood increased, the sales of sherry were in decline. That led to distillers starting the process of getting casks made specifically for them, and having the bodegas fill them with sherry for two or three years before shipping the casks to Scotland.