Review: Steam distilled spirits from fermented grape pomace

Grape pomace is the solid residue left after juice extraction from grapes, and represents in Mediterranean countries the most important by-product of the winemaking industry. Steam distillation of fermented grape pomace will eventually produce a spirit, designated as bagaceira in Portugal, orujo in Spain and grappa in Italy. This paper comprehensively reviews fundamental a nd applied aspects of the manufacture of these spirits, encompassing their composition as well as metabolic reactions and microbial ecology that deter mine such composition during fermentation. These spirits adhere to maximum levels of methanol (potential toxic compound) and 2-butanol (potential flav or defect) fixed by EC regulations. Available studies pertaining to bagacei ra, orujo and grappa have indicated that the final quality of these spirits depends strongly on the quality of the fresh grapes, the storage condition s, and the distillation equipment and procedure employed.