How do we authenticate what's believed to be the world's oldest whisky?

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A discovery like the whisky found hidden at Blair Castle is hugely significant. Not only do they form an important part of the heritage of the estate, but they are also artefacts from the wider history of distilling. This latter point cannot be understated and, believed to be close to two-centuries old, their appearance is a shock that reclaims a lost era of whisky production from the unknown. As such, there are certain challenges, both obvious and complex, when it comes to authenticating such items.

At Whisky Auctioneer we take the issue of counterfeit whisky, its detection, and the prevention of its circulation incredibly seriously. The procedures involved in doing so require, firstly, the establishment of the provenance of a bottle and, secondly, an assessment of its presentation in order to determine accuracy or inconsistency with what we expect from the appearance of the labels, bottle types, closures and various other elements. As an auctioneer, opening a bottle to assess the whisky itself is generally not a viable option, however we can make confident and reliable assertions to the authenticity of the liquid inside a bottle by developing an expertise in everything on the outside.

These procedures have been developed through years of experience, record-keeping, and research, meaning they are ultimately predicated upon what is knowable and verifiable about a particular bottle of whisky. An initial inspection of the bottles confirmed that while the glass bottles appear to be of 19th century origin, the wax seal and cork closures are in line with methods we have observed from the 1930s and earlier decades. Beyond this however, with the Blair Castle whisky we are dealing with the unknown. A discovery like this was entirely unprecedented and the bottles are likely the only of their kind still in existence. There is no scope for additional comparative study, neither via our standard techniques nor a sensory assessment of the liquid and as such, alternative methodology is required.

Joe Wilson inspecting bottles of the Blair Castle c.1833 Scotch Whisky


Having said that, provenance is still the starting point. To set the scene, the bottles were discovered in late 2022 by Blair Castle resident trustee, Bertie Troughton. While clearing out storage areas one day, he discovered an old cellar bin that contained, among other things, around 40 bottles of whisky. Alongside them was a wooden plaque that reads “Whiskey, small still,” casked 1833, bottled 1841 and rebottled in 1932. After discussing the find with his mother, Bertie then established that elder generations of the family had been aware of the existence of these bottles, although they had been largely forgotten having been secreted away for so many years. With the Atholl Estates covering huge tracts of Perthshire at this time, known to be home to a number of both legitimate and illicit distillers, it is believed that the castle acquired the cask from one of these tenants.

Thankfully, the Blair Castle archives are some of the deepest and most comprehensive of any heritage site in Scotland. This does not mean they are complete, however, and despite best efforts no direct reference to these particular bottles has been found. This means that unfortunately we are unable to say with any authority that the dates on the plaque are correct to-the-year, however research has enabled us to build a case by which we have been able to alleviate certain doubts.

Firstly, items known as Bin Books (or cellar inventories) have been found that show both the storage of bottled and in-cask whiskies during the time periods reflected on the plaque. One dated 1834, for example, specifically notes a cask containing 40 gallons be contained in bin 65. There is also evidence of spirits being bottled at the castle, including in the year 1841 when a Household Book details the filling of four-dozen bottles of brandy. Evidence of distilling on the Atholl Estates is also plentiful, with archival material that includes distilling equipment, as well as letters between estate factors and tenants that reference whisky production there in the early 19th century.

While the provenance obtained leaves us unable to confirm the vintage and bottling years stated on the plaque found with the bottles, we believe that the supporting information that was uncovered provides a solid foundation for the belief that they are highly possible, or even probable. As such, the decision was made to progress with the whisky and move authentication to a scientific analysis stage. The number of bottles of the whisky discovered was not only significant in that it has facilitated the bringing of 24 of them to market, but also that some were able to be opened. All scientific analysis requires samples to be taken, meaning in most instances it is not an option given bottles must remain sealed in order to be sold at auction. Mostly it is also not required given our ability to authenticate bottles from other means, however in cases like this where we are dealing with incredibly old and incomparable bottles, it is a necessity.

Keren Guthrie, Archivist at Blair Castle, looking at archival references to whisky


The first and most obvious requirement was to establish that the liquid in the bottles was indeed whisky. To achieve this, a sample was submitted to the Scotch Whisky Research Institute (SWRI) in Edinburgh where gas chromatography and an additional analysis of maturation related congeners was conducted. The results of this testing found that, allowing for the differences in raw materials and production methods, this was a whisky with a good probability of being produced in accordance with malt whisky distilling practices of the time. It was also confirmed that the whisky was aged in a barrel made from oak. We are pleased to be continuing this partnership with SWRI and another lab at the University of Edinburgh in order to conduct further and more in-depth analysis to be published at a later date.

A second sample was then submitted to the Scottish Universities Environmental Research Centre in Glasgow where a radiocarbon dating analysis was conducted – this is a method by which the age of an object containing organic material can be determined by using the properties of radiocarbon, a radioactive isotope of carbon. The testing produced an F14C value of 0.9846 ± 0.0025, calibration of which gave a range of potential 19th century vintages, including that of 1833.

While carbon dating is valuable science, it is sadly not an exact science and such testing will never provide answers to those looking for specific vintages. What it can do, however, is eliminate doubts about the authenticity of a claim to a whisky having a certain dating. Without better archival evidence to corroborate the 1833 vintage stated by the plaque found with the whisky, this sadly cannot be confirmed. What we do know, however, is that this is a very, very old Scotch whisky. We know that whisky was produced on the Atholl Estates, stored at Blair Castle both in cask and bottle in the early 19th century, and that residents have long been aware of the existence of these particular examples – including the stock take and cellar consolidation that is thought to have resulted in the 1932 rebottling of the whisky that is referred to on its plaque.

For our part, what we know is that this is an incredible opportunity that could not be overlooked just because the specifics of a vintage could not be ascertained. For an exceptionally old (potentially the oldest) Scotch whisky to have been found bottled in such numbers has created an almost certainly unrepeatable opportunity to allow others the chance to collect, sample and ultimately experience a fascinating artefact from the history of the spirit we know and love.