A study on the composition of distillates obtained from smoked marc

Fermented marc is the traditional raw material of grappa. The effects of a controlled smoking process applied to fermented marc for 120, 240 and 460 min on the composition of the corresponding distillates (spirits at ca. 40%, v/v ethanol) were studied. The smoked marc samples were distilled using a pilot plant and the distillates collected by volume and analysed. Longer was the exposition of the marc samples to the smoking process higher resulted the reduction of ethanol, higher alcohols and ethyl esters. Instead, the volatile phenols and the polycyclic aromatic hydrocarbons (PAHs) increased with the extended of smoking time. Good correlations between the time of smoking and the concentrations of higher alcohols and PAHs have been found. In relation to the content of benzo(a)pyrene, it must be noticed that it was detected always in concentrations which did not exceed the limit of 0.03 μg kg−1.