Without wood, Scotch wouldn’t have a lot going for it. Many of the flavors that come through in a fine Scotch are imparted by the barrel, notes Stuart MacPherson, Master of Wood at The Macallan, one of the first distilleries in Scotland to be legally licensed and one of the world's leading single malt whiskies.
"The character of the distillery, the ingredients used, the size and shape of the stills and its location are all important, but the major factor is the type of oak cask used for maturation," says MacPherson, who has spent much of his life studying the art of cooperage and what goes into the perfect barrel. "Wood is full of naturally occurring oils called vanillins. It is these oils that are drawn out of the cask by the spirit and over the period of maturation they add to the whisky’s flavor profile."
MacPherson was drawn to cooperage at a young age -- but it wasn't his first career choice. "I happened to work in the cooperage during the school summer holidays and became fascinated how casks were repaired and constructed, plus the skill and physical effort which was involved," MacPherson recalls. "After working for six weeks in the cooperage, I went back to school to carry on my studies, but all the time thinking about this fascinating and wonderful craft. After a long discussion with my parents I decided that this was the career I wanted to follow and have never looked back."
So MacPherson has devoted his life to barrels -- specifically oak barrels.
Historically, MacPherson says any type of wood could be used to make casks but now, by law, they now must be constructed of oak. "Oak is selected for its toughness," he says adding that it is also easy to work with- it can be bent by heat without splitting and its tight grain prevents leaking, yet it is porous, allowing oxygen in and out of the cask.
All Scotch whiskey must be matured in oak barrels, but not all oak is created equal. There are two fundamentally different species of oak, MacPherson says: American white oak (Quercus Alba) and the various European oak species (Quercus Robur and Petrea). American white oak grows faster and has a mellower, finer and more contained aroma, while European oak provides full, intense aromas and more tannins. An American oak can be harvested after 70 years, while the slower-growing European oak takes at least 100 years to reach harvestable size.
While MacPherson says there is not a specific wood or cask that is particularly suited to luxury products, The Macallan mostly uses Spanish oak and on occasion American oak, seasoned with sherry, which gives that whisky a lighter color and brighter vanilla and citrus fruit characteristics.
"Sherry seasoned casks are at the very heart of The Macallan, and this defining factor has contributed to the fame of the brand today," MacPherson says. "Each expression has its own profile and character taken from the type of wood and time of maturation to allow us to create our 100 percent naturally colored products."
In general, the single malt segment is enjoying solid progress, driven largely by The Macallan. With several high-end launches over the past few years, including that of The Macallan Rare Cask, a highly coveted expression aged in the top 1 percent of Sherry oak barrels from The Macallan distillery, the brand's reputation for uncompromising quality and upscale positioning have become solidly established.
With the growth of The Macallan, ensuring that supply of new barrels is available is critical --MacPherson has recently taken on the role of Spanish operations manager, concentrating on working with cask suppliers and seasoning bodegas in Spain.
"As the demand for Macallan increases worldwide, so does the requirement for new casks," he says, adding that cooperages have to plan far ahead to have sufficient timber in stock --the long natural air drying process means that from the felling of the trees to the delivery to the distillery takes up to six years.
These days, 90 percent of the world's whisky is aged in American oak casks, making Macallan something of an outlier, and one with expensive taste. The Spanish oak barrels Macallan favors can cost 10 times as much as American oak, due in part to the decline in the sherry industry and growth in the bourbon industry, meaning those used barrels are easier to come by. MacPherson says Spanish oak, primarily from the Galicia region of northern Spain, yields a spicier finished product, with notes of sherry, dried fruits like sultanas, raisins, and candied peel, as well as cinnamon, nutmeg, wood, caramel, orange, and Christmas cake. By contrast, MacPherson says American oak age imparts flavors of vanilla, honey, coconut, almonds, hazelnuts, butterscotch, fudge, and ginger spice.
Whatever your pleasure, high-end whiskey is seeing solid growth across the board. Consumption of $100-and-above bottles of spirits increased by 60% in 2013, and The Macallan, as the second-largest single malt by volume in the U.S., saw 15.1% growth, to 214,000 cases, last year.
