Definition: Cooperage

This term refers both to the profession of cooper and to the objects they make. Some large, renowned estates have their own cooperage, so that they can better control the provenance of the wood, its drying and the delicate charring of the inside of the barrel. Although mechanised, the manufacture of casks and barrels has remained very traditional.

The main stages are:

The selection of logs in the forest, a selection made on site by the cooper. After felling, the trees are pruned, cut into logs and transported to the cooper's workshop. It is generally oak trees over a hundred years old that are selected for cooperage. The logs are sawn into billets, which are split along the grain into quarters, then into doubles and finally into staves. At this stage, the staves are left in piles in the open air for several years to dry, but also to be washed by rainwater, which removes unwanted coarse tannins from the wood. The staves are then transformed into body staves or bottom staves according to a very precise cut that will ensure the barrel is watertight.

The cooper assembles the staves using mounting hoops. Before bending, the cooper places a brazier with a fire of wood chips inside the rosette, whose flames heat the inside of the staves. To help soften the wood fibres gradually and prevent the wood from overheating, he wets both sides of the barrel under construction with a mop. Once all the hoops are in place, the body of the barrel is complete. The ends of the staves are bevelled (the jable) so that they can be assembled at the bottom. The hoops are assembled using wooden pegs, with a river rush joint between each stave. The assembly hoops are replaced one by one with the final galvanised steel hoops. All that remains is to drill the bunghole stave and test the barrel by filling it with cold water and compressed air to clean the inside and ensure it is watertight. Finally, the finishing work, planing, polishing and signing are carried out. The barrels of the great châteaux are often fitted with chestnut finishing hoops at the ends, bound with wicker. This type of barrel is more attractive, ensures better rolling, prevents wear and tear on the floor and reduces the risk of injury during handling.