For all the attention given to malting and peat, to age, region or even still size, what's often left out of the discussion about what makes Scotch whisky so popular is wood. Barrels of diverse origin, which have nearly always held something other than Scotch and often have been put through incredibly precise steps of reconditioning, represent one of the industry's critical secrets.
One of the pioneers of finishing Scotch whisky in various used barrels, Dr. Bill Lumsden, Head of Distilling & Whisky Creation at The Glenmorangie Company, is unequivocal: "All the different parts of the process are important, from the source of water to the choice of raw materials to a well-controlled distillation. But at the end of the day it doesn't matter how good your spirit is; if you don't have good quality oak you simply can't make good whisky."
The wood's work is responsible for up to 70% of the flavor in whisky, says Dr. Nicholas Morgan, Head of Whisky Outreach at Diageo, and that's due to a number of causes. "The first is subtractive, that's when the cask is taking out undesirable elements in new make spirit. You don't want many of the heavy sulphury elements, and the wood manages that," he explains. "Secondly is the additive process, which begins about halfway through and that's when wood starts giving character."
American oak, specifically once-used bourbon barrels, is known for adding vanilla and sweet flavors.The third process is interactive, when flavors and aromas mingle and produce a rounded quality that completes the whisky. "It can take six, eight, ten or 12 years, but you need to get all those parts of the process right to make sure you get a good whisky," says Morgan. Read more>>