In the world of Scotch whisky, two is the magic number. Twice-distilled spirit has been the bedrock of Scotland’s national drink for centuries. But deep in the highlands and on the wave-battered coast of Campbeltown, a quiet rebellion is taking place – one calculated to three decimal places.

From Mortlach’s precisely calculated 2.81 times distillation to Springbank’s mythical two-and-a-half times process, these mathematical mavericks are proving that thinking beyond double distillation can yield extraordinary results. Welcome to the world of fractional distillation, where the most interesting whiskies often come from the most unusual numbers.

The Beast of Dufftown’s Mathematical Mystery

Deep in Speyside, Mortlach Distillery performs what might be whisky’s most complex ballet of distillation. While most Scottish distilleries stick to distilling their spirit twice, Mortlach proudly declares their whisky is distilled 2.81 times – a peculiarly precise figure that has puzzled whisky enthusiasts for generations.

The secret lies in an intricate dance between six stills of varying shapes and sizes, including a diminutive still affectionately known as the ‘Wee Witchie’. Two stills operate conventionally, producing the first spirit stream through standard double distillation. But it’s what happens next that makes Mortlach unique.

The remaining four stills create two additional spirit streams through an elaborate process. The distillery splits the output from two wash stills between two spirit stills – 80% flows into one, while the remaining 20% enters the Wee Witchie. This weaker portion undergoes an additional distillation, creating a third spirit stream that’s been distilled three times.

When these three streams combine, condensed through traditional worm tub condensers, they create what locals call the ‘Beast of Dufftown’ – a supremely meaty, sulphurous spirit. This robust character, born from this mathematical oddity of distillation, has become Mortlach’s signature, proving that sometimes the most distinctive whiskies come from breaking conventional rules.

The Art of Half Measures: When 2.5 Times Equals Excellence

In the quaint coastal town of Campbeltown, Springbank Distillery has perfected what seems mathematically improbable – distilling whisky two-and-a-half times. This isn’t a marketing gimmick but rather a meticulously calculated process that has helped define their distinctive spirit for generations.

The technique begins conventionally enough, with malted barley being distilled in the wash still to produce low wines. But then things get interesting. The distillery splits these low wines, with one portion undergoing an additional distillation to create feints. These feints are then mixed with the remaining low wines before a final distillation in the spirit still. The result? A complex spirit where some portions have been distilled twice, others three times, averaging out to that mythical 2.5 figure.

Until 2007, another distillery, Benrinnes in Speyside, employed its own version of partial triple distillation. Their process involved separating strong and weak feints, with the weaker portion getting an extra run through an intermediate still. Though they’ve since switched to conventional double distillation, this historical approach helped establish their reputation for producing remarkably full-bodied whiskies.

These unconventional methods aren’t merely mathematical curiosities – they create whiskies of exceptional complexity. Springbank’s approach yields a spirit with both the robustness of double-distilled whisky and the refinement of triple distillation, while Benrinnes’ legacy lives on in their distinctively meaty character.

Innovation in the Spirit of Tradition

As Scotland’s whisky industry evolves, these mathematical mavericks have shown that thinking outside the traditional double-distillation box can yield extraordinary results. Modern distilleries like The Glasgow Distillery Company are taking note, experimenting with their own innovative approaches to distillation and maturation.

Yet these numerical experiments represent more than just technical curiosity. They demonstrate how Scotland’s whisky industry continues to find new paths to excellence while honouring its heritage. In an era where efficiency often trumps tradition, these labour-intensive methods prove that sometimes the most rewarding innovations come from embracing complexity rather than avoiding it.

The question for Scotland’s next generation of distillers isn’t whether to follow tradition or embrace innovation – it’s how to do both at once, just as Mortlach and Springbank have done for generations.

Read the full article at Rebel Distilleries Are Using Bizarre Distillation Numbers