The seasoning of the staves is accompanied, in addition to the drying, by the elimination of unwanted green tannins. During the first 6 months of seasoning, the water-soluble substance contained in these green tannins is eliminated from the wood (green wood > 60% moisture content) by rainfall. Tonnellerie Saury also sprays the wood with water to facilitate and accentuate this process.
On arrival at the cooperage, the staves are sprayed with water before being transferred to the seasoning yard. The stacks of staves are sprayed in a dedicated area equipped with an automated horizontal spraying system, which goes off every 30 minutes, wettening the staves to the core. The spraying cycles last about 10 days, during which 70-80% of the undesirable tannins are eliminated. After this process, the staves’ moisture content gradually decreases and the wood fibres tighten up. The extractable tannins of interest to us remain trapped inside the staves.
The water used for this operation is drawn from the water table and then treated with UV lamps before spraying. Each cycle uses 250 m3 of water. The water is then collected in a treatment tank before being returned to the stormwater system.
