Aroma compounds in barrel aged apple distillates from two different distillation techniques

The major fermentation and maturation related congeners in apple distillates from two different distillation techniques (alembic and column), matured in oak for 18 months, were measured by GC-MS and HPLC. Together with a higher ethanol content, column distillates had higher ethyl acetate, methanol and n-propanol levels compared with alembic distillates. A higher content of acetaldehyde was characteristic of the alembic distillates. The concentrations of i-butanol, n-butanol, amyl alcohols and n-hexanol were not affected by the distillation technique used. Increasing the ageing time of distillates in oak resulted in an increase in the contents of acetaldehyde, ethyl acetate and amyl alcohols while the content of methanol decreased during ageing. Throughout ageing, there were no significant changes in the concentrations of n-propanol, i-butanol, n-butanol and n-hexanol. Among the maturation related compounds, gallic acid, ellagic acid, vanillin and syringaldehyde were determined in apple distillates with ellagic acid being the most abundant. The contents of gallic acid and ellagic acid increased during ageing whereas vanillin and syringaldehyde slightly increased throughout the 18 months of maturation