There is some truth to this.

It is hard to separate the folktales from the verifiable history here, as most of the academic sources remain vague on this point.

Storage in Wooden barrels

By the eighteenth century, Scotch whiskey production generally repurposed wine, port, and sherry casks to transport their product. Several competing explanations are given for this: it could arise from widespread illicit distillation of Whiskey in Scotland from roughly 1700-1830, with smugglers using these casks to disguise their product during shipment. It could be simply that new casks were expensive in Scotland, so distillers repurposed casks to save money, especially given the large number of small-scale producers.

Whiskey did undergo a pre-shipment storage period (in wooden barrels) due to the seasonal nature of Whiskey production. Several months of unavoidable maturation could also occur when casks were shipped internationally. Whiskey was then sold in barrels, with bottling remaining rare until the late-nineteenth century. Publicans would buy a barrel of whiskey, and then transfer whiskey from the barrel to a decanter for serving.

But while Whiskey did inevitably spend some time maturing in wooden casks, “the majority of whiskey distilled in the eighteenth and nineteenth centuries [was] probably drunk unmatured” (Stewart and Russel, 2014). It would be more accurate to say whiskey was stored in wooden barrels than to say it was “aged” in wooden barrels.

Intentional maturation and the Scotch Boom

At some point between about 1850 and 1900, it was discovered that maturation in wooden casks improved the flavor profile of Whiskey. This development coincided with a massive expansion of Scotch Whiskey exports.

The Scotch boom was driven by earlier 1824 reforms which had lowered the excise taxes on Scottish distillers causing market consolidation and a shift to larger-scale (and legal) production, and the development of blended whiskeys which were likely more acceptable to the market than single-malts. Legal changes in 1868 also allowed distillers to mature whiskey in casks for up to twenty years before having to pay excise taxes on it, which likely gave a boost to cask maturation.

But the real expansion in Scotch whiskey exports is usually tied to the decimation of European wine production by Phylloxera, an aphid-like commercial pest which destroys grapevines. Native to North America, Phylloxera reached France in the 1860’s and destroyed 60-90% of European vineyards between 1870 and 1880. The resulting shortages of wine and brandy left upper-class British drinkers searching for replacement beverages. Blended Scotch production largely met this demand.

France?

As for your story. France did not have a King by this point, the Second French Empire had Emperor Napoleon III from 1852-1870. But I have not seen any evidence that any French monarch or French exports had major effect on the development of aged Whiskey. It would make more sense for the longer ocean-voyages of whiskey sent to far-off colonies to have spurred intentional cask maturation. Most of the sources I’ve read describe the boom as initially limited to the British market, and none mentioned France.

So while the rise of barrel-aged Whiskey likely occurred in the same period as the Whiskey boom and the Phylloxera blight, this is likely coincidence rather than causation.

The superiority of aged whiskey was widely-accepted enough by 1902 that the Oxford English Dictionary stated “a lengthy process of maturation in sherry casks is required to make whisky a wholesome beverage.” But it was not until 1915 that a set maturation time was established in Britain, with Whiskey now required to spend 3 years in the cask. Though multiple sources attributed the law to government attempts to reduce drunkenness in munitions factories and the homefront; and distillers’ desire to raise prices; rather than any actual concern about the quality of whiskey.

Conclusion

I would say there were few rules in Scottish Whiskey production prior to the nineteenth century. Distillers added honey, botanicals, and a wide range of other flavoring; they distilled from malt or grain or a combination of various things. A large proportion of Whiskey was small batch and either sold illicitly or consumed locally. The processes were not well documented, and this history has largely been obscured by subsequent corporate marketing about 'timeless traditions' and the establishment of formal standards and rules for Scotch whiskey production. So prior to the widespread adoption of cask maturation after 1850, there may have been regional or hyperlocal traditions of aging whiskeys, but nothing concrete in the sources I have read.

Sources:

• Bevan, Andrew. "Mediterranean containerization." Current Anthropology 55.4 (2014): 387-418.
• Lockhart, Robert Bruce. Scotch: the whisky of Scotland in fact and story. Neil Wilson Publishing, 2012.
• Minnick, Fred. Whiskey Women. Potomac Books, Inc., 2013.
• Stewart, Graham, and Inge Russell, eds. Whisky: Technology, Production and Marketing. Elsevier, 2014.
• Work, Henry H. Wood, whiskey and wine: A history of barrels. Reaktion Books, 2014.

I’d just like to correct one small part of your premise, namely the suggestion that “peat-smoked barley whiskey was invented in Scotland”. This might go a little overboard given it is a throw away line in your broader question, but I can’t help myself haha

Although Scotland and especially Islay is known today for its smoky, peated whiskeys this does not mean that they ‘invented’ the idea. Obviously pinpointing agricultural traditions like this to any definitive birthplace is basically impossible, but in a broad sense to claim that “Scotland” invented peated whisky is absolutely not true. In actual fact we can trace the use of peat-smoked whisky (or what would become whisky) to Ireland for every bit as long.

The reason I place Scotland in inverted commas above is because it’s also misleading to think of entirely discrete nation states and borders in pre-modern times. Now that's not to say that there were no ‘national’ forms of identity, but these were very different from what we would recognise today. Ireland and the highlands/western isles of Scotland formed a common cultural unit, a single Gaelic world or Gaedhealtacht.

The western isles of Scotland - including Islay - were particularly connected to the Ulster coast. Far from a dividing line, the Irish sea acted as a unifying feature for trade and travel. You can look to early medieval kingdoms like Dál Riata, or you can look to connections in later centuries like the powerful Lords of the Isles and the MacDonnell’s of Antrim/MacDonald’s of Scotland. One example I like is a poem addressed to Alexander MacDonald, third lord of the Isles (c. 1423-49) whom it describes as both “the leopard of Islay” and “Pride of the Gaedhil |The champion of Ulster”.

Now what the hell does this have to do with whiskey! Well this is simply to emphasise that Islay and Ireland weren’t two totally different places for much of history; they were effectively the same place. Or at least part of a shared cultural unit, linked by family, history, language and trade, even though they were not directly linked politically. Again this goes for the whole of the western Scottish seaboard and much of the highlands. This area - Argyll, that is - is even named for these connections. It comes from airer Goídel (borderland of the Gaels).

The earliest reference to distillation in Ireland comes over a century earlier than the evidence we have for Scotland (from the “Red Book of Ossory” c.1324 vs. a 1494 reference in the Scottish Exchequer Rolls). Now this isn’t a reference to whisky as we would know it. This was a medicinal product which would have been doctored with herbs, a bit like modern liqueurs or even gin. Actually the flavour most associated with this earlier stuff is anise or licqorice. It took many many centuries for this aqua vitae or uisce beatha (usquebaugh, as it became known to English speakers) to eventually become anything that we would begin to recognise as whiskey. Originally it would have been distilled from wine too, though naturally enough we do see grain before long.

The main thing to note though is that within this common Gaelic World, ie. Ireland and these parts of Scotland, people quickly develop a fondness for this medicinal substance, knocking it back as a recreational drink….so it moves from this scholastic context in the late medieval period into a broader agricultural one. Particularly within the world of Gaelic hosting, feasting and hospitality.

As we enter the early modern period we start to see other agricultural distilled spirits emerge more clearly out of the original usquebaugh (though this herb-flavoured stuff lingers on into the early eighteenth century too as a kind of aristocratic holdover). This process is taking place in Ireland, but of course it’s also happening in those Gaelic parts of Scotland too. Now the old Medieval Gaedhealtacht collapsed as we move from the 17th century to the 18th, but these cultural links persist for a long time yet of course. History is obviously fluid that way.

In Ireland we find something called bulcán (or bulcaan, to English observers) - from the Irish buille ceann, meaning knock/blow to the head - which was distilled from malted oats and malted barley. Using what fuel source they had available to them, these malted grains were naturally smoked with peat (or turf as we say in Ireland). Killowen distillery have released a revived version of this drink actually. Around about the same time we find in the Scottish isles a drink called Trestarig which is triple distilled from oats, and ‘Usquebaugh-baul’ which is also made from oats but distilled four times.

Those shared early modern traditions would eventually morph into what was known as poitín in Ireland and poit dhubh in Scotland, proto-whiskey made in the illicit stills of the remote islands and glens. Although the specific recipes or mashbills of these proto-modern ‘whiskeys’ were extremely variable in step with whatever the hell was available locally, the essential point is that the concept of drying malted grains using peat or turf emerged in Ireland exactly at the same time as it did in Scotland. It was the same tradition within the same shared cultural space and basically the same landscape. They used peat because that was what they had to hand.

In Scotland these illicit stills crystallised into the distilleries we know today - like Laphroaig and Lagavulin. This was a consequence of tax incentives. Unfortunately the Irish excise did not have the same foresight to coax the illicit distillers there to turn legal and eventually the tradition died out. So in hindsight we look back to Islay and Scotland as smoky and peated, and Ireland as light and fruity. But the reality is, of course, much different. Now the distilling tradition further south, in Dublin and elsewhere, was different. But North Ulster shared this tradition with those parts of Scotland to which it was historically linked.

We can see evidence of this peated tradition within Irish whiskey/poitín well into the late 18th and early 19th century too. For instance, one Belfast magazine noted in 1809 that:

“In taverns, where smokey whiskey is sold, as much is charged for it as for old Antigua rum; and if we purchase it by the gallon, we will pay from two to three shillings more for it than for the whiskey that has paid the excise duty - but then we are told, it is good Malt whiskey, real peat reek, or right good pot-yean…”

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