The Coopers Art
The weathered or kiln-dried, oak planks need to be carefully shaped in to tight-fitting staves. This was where the experience of the dry cooper excelled over all others.
Originally there were four grades of coopering skill – white, dry, dry-tight and wet – depending on the suitability of a cask for it’s purpose. Wet coopers were at the pinnacle of their craft making casks with such precision that they were leak-proof. The cooper, like the mason, commanded respect in society.
The challenge is to make 35, three foot long staves (depending on size) fit together – without glues, nails or fillers – in to a solid, water-tight container in three hours.
To achieve this each stave needs to be scalloped and curved on both sides; bevelled along both edges and tapered at each end.
Once this was done by hand, using wonderfully named tools such as a crumming knife, trussing adze, topping plane, chiv, croze and a roundshave.
Now each cut is performed by a specialised dedicated lathe. Then there is the angle between staves that must be precise, dependent on the diameter and circumference.
The American bourbon barrel is the industry standard. Racked and palletised for storage, the typical belly bulge of the cask has evolved in to a slimmer, less rotund form, as manoeuvrability has become mechanised and stowage methods have changed.
While beer is now transported in aluminium kegs, whisky, thankfully, is still matured in oak casks by law in Scotland, yet oddly not so in Ireland. Admire the skill, history and craftsmanship that each cask represents. It’s as humbling as the work of art it represents.
(The main photograph is of the Cooperage that was once on this site.)
Oak Tree Cutting Plan
Staves Scalloped and Curved on Both Sides
Cross Section of Stave
The anatomy of the staves
1. Hollowing (Evidage)
2. Backing (Dolage)
3. Tapering, beveling (Ecourtage)
4. Groomed to hovel shape (Bouge)
The Coopers Precision
L’Art de la Tonnellerie