Abstract: The present invention relates to a process permitting the modification of the chemical composition of the inner face of a barrel, consisting in heating and in moistening the inner face of the shell (1) of this barrel, characterized in that it consists in alternately heating and moistening, according to a specified heating power and liquid flow rate, and for a specified time, the heating being distributed over the entire height of the shell.It also relates to a machine implementing this process and comprising a rotating support (12), heating means (19) and moistening means (20, 21, 22) which are vertically displaceable with respect to the main axis of the barrel.Application: barrels for wines and alcohols.