Phenolic compounds in oak wood extracts used in the ageing of brandies

The oak wood extracts used in brandy production are extremely varied because of the different ways in which they are made: by infusion, by boiling or by maceration, with or without prior physical or chemical treatment of the wood. Such extracts release a large quantity of phenolic compounds and a very small amount of partially degraded lignin into the brandy, unlike spirits aged in oak barrels. Among monomer compounds derived from lignin, the presence of vanillic and syringic acids, vanillin, syringaldehyde, coniferaldehyde and sinapaldehyde can be noted. In the wood extracts, phenolic compounds and aromatic acids frequently dominate the ligno‐complex and aromatic aldehydes respectively, which is not the case in brandies. Two samples of liquid extracts of oak wood displayed statistically aberrant vanillin contents.