The sharp, repetitive sound of hammers steadily beating copper into shape echoes around the fabrication hall on an industrial estate just outside Edinburgh. At McMillan Coppersmiths in Prestonpans, metal workers wield heavy wooden mallets, steel hammers and steel moulding tools called flatteners as they coax curved sheets of copper into new stills for Scotland’s malt whisky distillers.
They talk about planishing, where the welds that join the seams in the rose-gold metal are hammered flat, and of tafting, where the copper is formed by their hammers into the gentle curves of the still around hefty steel moulds.
In a world where factories make parts with 3D printers, robots and computer-controlled laser cutters, whisky stills at McMillan’s are handmade. The coppersmiths estimate it can take a million hammer blows to form each still – 30,000 hammer strikes a day for weeks on end.
They use chalk and marker pens, metal rulers and compasses to mark out where to cut. On the curved shoulders and the tall swan neck which transports the heated spirit vapour as it cools and condenses, hammer strikes are faintly visible. The largest stills will take 15,000 hours of work.
“You’re pretty much given the freedom to create art,” said Louis Black, 27, one of McMillan’s 24 coppersmiths, who include several young apprentices. Once the flat sheets of copper have been cut by guillotines or water jets and rolled into curves by machine, the shaping is largely done by eye. “We’re hardly using tape measures or any sort of measuring equipment. Every hammer blow makes a difference,” Black said.
McMillan’s coppersmiths have been finishing two new stills for a new malt whisky firm, Ardgowan, at Inverkip on the Firth of Clyde. Business is booming. The firm also supplies whisky, rum, tequila and gin distilleries around the world, from the Lake District to China, South Korea, Mexico and Australia.
Martin McAdam, the founder of Ardgowan, said their stills, which were finished in late October, were designed to work with his distillery’s new technique to recycle all the waste heat from the spirit production cycle, cutting energy use by 40%.
Copper stills are mandated by law for Scottish malt whisky; using the premier Scottish stillmaker made sense. “We love the ethic of this,” he said. “In a world where we have automation everywhere, here’s something which is fundamentally a handworked, crafted object. We love the idea that 2m hammer blows have gone into our stills.”
Despite the costs involved, copper is highly prized by distillers because of its particular chemical properties: as well as being an excellent conductor of heat, it strips out unwanted sulphides from the spirit and encourages the production of esthers, which adds to the whisky’s taste. And once a special finishing lacquer has been applied, it adds a salmon pink glow to the metal.
Robert Goudie, McMillan’s operations manager, said every still was different. Each company’s master distiller will have a specific design, hoping to maximise the characteristics of their whisky. Some visit regularly while the stills are being made. He said theirs is the only stillmaker that would hammer out every weld.
“The heritage and traditions of the Scotch whisky industry are key,” Goudie said. “New distilleries have their concept and design, and we build to that design. You’ve got conical shapes, round shapes and tapered as well. We’ve got to make sure it’s right.”