Oak barrels and booze have a long and intimate relationship. Prior to the 3rd century CE, the storage vessel of choice for storage and transport of food and drink was the clay amphora.
The origin of clay amphorae has been lost in the mists of time, but there is archeological evidence of their existence as far back as 8000 years ago in the Mediterranean and Mesopotamian regions.
The usage of clay amphorae peaked in the days of the Roman Empire. Essentials like wine and olive oil were transported by ship to all corners of the Empire, and clay amphorae were the preferred vessel.
If you have never seen an amphora in a museum, it is a clay container with a tapered bottom and a long slim neck to minimize oxygen contact with the contents. Handles were typically attached to each side to make transport easier.
As the Roman Empire expanded and came into contact with other cultures, new technologies would be adopted. It was in the first century BCE that the Julius Caesar began military incursions into the land of the Gauls, in what is now modern-day France, quickly adding that territory to the Roman Empire.
Much to the surprise of the Roman soldiers, the Gauls transported their beer in wooden barrels, which were far easier to transport over land than clay amphorae.
The Roman armies quickly switched over from clay amphorae to wooden barrels for transporting goods through military supply lines, and the rest of the Empire followed suit shortly after.
By the 3rd century CE, clay amphorae had almost entirely disappeared, not only because of the logistical advantages of barrels, but it was a happy coincidence that wine stored in oak barrels was much improved after contact with the wood.
It was around this time that the Romans recognized that the region of modern-day Bordeaux produced exceptional wines, and with wooden barrels, those wines could be more efficiently transported throughout the Empire.
The winemakers of the day did not understand the chemistry involved with maturing wine in oak, but it quickly became apparent that a few months in oak would take the tannic sharpness off a wine, and imbue notes of vanilla, smoke, and other attractive flavours.
Centuries later, greater understanding of the chemical composition of wood explained that the vanillin and lignin compounds that make up wood fibres were interacting with the compounds in the wine, and the ability to make the barrels practically airtight avoided the oxidation and spoilage that was so common with the less precise closures on clay amphorae.
Today, nearly two millennia later, the wines of Bordeaux are still the gold standard by which all others are judged, and are still aged in oak barrels handcrafted by local coopers.
Different types of booze will use oak barrels in various ways. By law, Bourbon from the USA must be aged in new oak barrels that have not previously been used.
Since a barrel can only be used once in a Bourbon distillery, a common practice is for the used barrels to be shipped to Europe, where they are used to age Scotch Whisky, Irish Whiskey, and assorted other spirits. We even have quite a few ex-Bourbon barrels right here in Canada, as our domestic distilling industry has no problem aging whisky in once-used barrels.
Since oak barrels are quite expensive, winemakers will try to reuse them several times. A new oak barrel will have the greatest effect on a wine, with the phenols in the wood softening the harsh tannins and adding bold and spicy notes to the wine.
Each time a wine barrel is used, it imparts less and less into the wine, and by the third usage, wine barrels are considered neutral, meaning they no longer significantly impact the taste of the wine.
Wineries will still use neutral oak barrels for storing wines, as the slight porosity in the wood grains allows miniscule amounts of oxygen to help mature the wine without spoiling.
Here in Canada, our domestic wine and whisky industries use mostly North American oak barrels for aging, with a smaller portion of the more expensive European oak imported from overseas.
Most North American oak grows in the eastern parts of the continent, so take a closer look at the treeline on your next vacation, and you might just spot some future wine barrels!