Barrel Making: Shaping and toasting

Research has shown that the heating process is one of the most important in barrel manufacture, modifying the wood’s physical and chemical composition and profoundly influencing any wine stored in the barrel. Heating allows the cooper to shape the barrel. Toasting degrades the wood structure and thereby produces aromatic compounds. There is controversy as to which type of toasting is best, with some suggesting that slower toasting is better for both the flavour and the structure of a wine matured in that barrel. A deep medium toast produces the most desirable character for most woods, but there is variation in effect depending on geographic origin of the wood, the seasoning of the wood, and the wine style. Ellagitannins from the barrel, which combine with phenolics in the wine to form new and softer tannin compounds and improve colour stability, are reduced by toasting.