The Macallan's Master Of Wood, Stewart MacPherson

The Macallan’s Master Of Wood, Stuart MacPherson (Photo by Rob McDougall)

If it weren’t for the humble barrel, we’d all be drinking white spirits. Wood barrels, which have been around since at least the Ancient Egyptians, provide 100% of the color of a spirit (unless artificially colored), and 50-90% of the flavor. As whisky is the spirit most often associated with barrel aging, I asked several industry experts about the relationship between barrels and the booze aged inside them.

I first spoke to Stuart MacPherson, who was appointed “Master of Wood” for The Macallan in 2012. Although not a distiller, he came up through the ranks by training as a cooper and is now solely responsible for purchasing and storing The Macallan’s wood and barrels. The Macallan is one of the three best-selling whisky brands in the world, alongside Glenfiddich and The Glenlivet. The Macallan is unusual- rather than switching to cheaper ex-bourbon casks as many other Scottish distilleries did in the 1930s, The Macallan uses 100% ex-sherry casks to age its whiskies.

“At The Macallan, up to 80 percent of our whisky’s characteristics and 100 percent of its natural color comes from our casks, which is why we invest significantly in our wood.” He continues, “Our casks are the single greatest contributor to our outstanding character, distinctive aromas and flavors, and the natural color of our whisky.”

He explains that selection starts with visiting the forests whose trees will provide wood for barrel staves. The Macallan gets some of its wood from Ohio, Missouri, and Kentucky, harvested when the trees are about seventy years old. MacPherson travels to the USA regularly to be directly involved with the selection. Other wood comes from forests in northern Spain and southern France.

The selected wood ships to cooperages in Jerez, Spain, for use in sherry casks. Once built, they’re toasted, which adds to the flavor of the final whiskies. They’re then seasoned with sherry for 12-18 months before being emptied and transported to The Macallan’s Speyside distillery.

“Toasting the barrel is very important during the whisky-making process,” MacPherson explains. “Wood is full of naturally-occurring oils called vanillins. These oils are drawn out of the cask by the spirit, and over the period of maturation, they add to the whisky’s flavor profile. The Macallan casks are toasted in a process that heats the wood for longer at a lower temperature. The slower temperature process is designed to break down different chemical compounds in the oak to yield spice notes like nutmeg and cloves and the desired subtly smoky aromas that oak is known to yield.”

Speyside in the northeast of Scotland is probably the best-known of the country’s five whisky regions (six, if you count the Islands as a separate region). Campbeltown in the southwest is less prominent, with only three working distilleries. At one of these, Glen Scotia, Master Distiller Iain McAlister, and his team are among many today experimenting with what different barrels bring to their whiskies.

“Over the last few years, we’ve used rum, tawny and ruby port, red wine, and this year, Pedro Ximénès barrels,” McAlister told me. “All have a direct association and historical connection to Campbeltown and its seafaring, industrious past, but importantly convey that wonderful oily, salty, fruit-flavored character, with a little peat influence.”

By way of example, I asked McAlister what tawny port barrels bring to Glen Scotia’s whiskies. I obviously picked the right one.

“Ah, tawny!” he replied with great enthusiasm. “I think some of the best whisky produced at the Glen Scotia distillery has come from tawny port casks. These add a lot of robustness, depth, and, when combined with peat, a very punchy fruit-flavor profile, one that encapsulates the region as it should be: Campbeltown, the region that produces a unique coastal whisky, a little dirty at times, but full of interesting flavor characters.”

On a different coast, in Seattle, Washington, is Westland Distillery. There, like MacPherson at The Macallan, blender Shane Armstrong is an enthusiast for sherry casks. Their Garryana Edition 6 special release matures in brandy and Pedro Ximénez sherry casks, plus casks made from the Garry Oak (also known as the Oregon oak), which grows all along the U.S. west coast, but particularly in the Pacific Northwest.

“Garry oak lends an ineffable spice,” Armstrong continues. “It’s more akin to French oak than American. The tannins can be tumultuous at times, and wood sugars are limited, so the crux is taming the former and leveling the latter.’

Not all barrel-aging experiments are successful, though, as Armstrong freely admitted. Westland aged one of its single malts for four years in a cask that had previously contained one of the world’s leading hot chili pepper sauces. He won’t name names, but you don’t have to be a genius to figure out what it was. They then bottled it at its full cask strength of 58.4% ABV (116.8 proof) and released it on April Fools Day, 2016, describing it as a ‘very (thank God!) limited edition’.

One reviewer described it as “one of the two worst whiskies he’d ever tasted in his life.” As Shane Armstrong succinctly put it: ‘Full term maturation in a hot pepper cask did not register many positive remarks. We call it our Mortal Sin.’

It is abundantly clear that barrels are fundamental to every aspect of what we know as whisky. The type of wood and prior contents of the barrels bring a lot to the aroma and taste of your favorite whiskies. However, the need to choose the right barrel is equally clear- just ask Shane Armstrong!

(Photo by Rob McDougall,,, 07856222103)