At Loch Lomond Distillery we have retained our own highly skilled coopers who continue to practice this age old trade on-site.
Back in the eighteenth century about one third of all goods for exports were contained in barrels.Wet coopers made barrels for containing liquids like beers, wines, cider, tar and molasses.
Dry coopers made those for flour, grains, fish, fruit, vegetables and almost anything that could be stored in a barrel. Other open ended items like pails and churns were also made by coopers.
At the same time someone started using oak barrels for whisky and it was soon realised that storing in oak for a period of time did much to improve the flavour of the end product. Initially any barrels that could be found were used, but the distillers soon came to realise that those that had previously been used for the storage of bourbon, port and sherry added a new smoothness and sweetness to the whisky. Eventually a shortage of barrels created the need for distillers to start making their own and from these roots the whisky cooperages were born.
More recently American bourbon casks have been widely used (pictured left).
To be called "bourbon" their whiskey must be aged in virgin oak casks which have been charred or fired on the inside.
The stencilled lettering on the cask pictured on the left tells us that this cask was originally used to store "The Old Grand Dad" Bourbon from Kentucky.
These bourbon casks become available to the Scotch whisky industry after just one use. They do, however, require some maintenance so that coopers nowadays are more often employed in barrel rebuild, repair and maintenance than barrel making.
As part of this process the "firing" of the barrels extends their life. This is done by decharring or shaving the barrels back to fresh wood and then refiring them to put a new carbon coat on the inside. All of these processes contribute to the flavour of the whisky.
Watch a video of a barrel being fired in our traditional cooperage.
Watch a video of a craftsman cooper at work on the barrel after firing.
(Note that these are quite large files and they may take time to download if you don't have broadband.)
Whisky barrels, being made from a natural material, cannot be perfectly sealed. Indeed the ability of the barrels to "breathe" is vital to the final taste of the product.
When a barrel is filled, there is an initial ‘in-drink’ of about 2% and then during the years that a barrel spends in the bonded warehouse about two percent of the contents are lost to evaporation each year.
When barrels are opened after say four years maturing, around 10% of the contents will have disappeared. This loss is known in the trade as "the angel's share"