The storage of grape marc: Limiting factor in the quality of the distillate

Waste grape skins thermal dehydration: potential release of colour, phenolic and aroma compounds into wine

“…High moisture content of waste grape skins together with a large production volume are the main factors affecting their exploitation because of spoilage and consequently loss of potential reuse (Corte´s et al, 2010). Following results present thermal dehydration as a pre-processing step to enhance handling and avoid spoilage of waste grape skins.…”

“…During the grape harvest season, regional manufacturers generate approximately 523,000 MT of grape marc (a mixture of grape skins, seeds and stalks) as a residue. In the present time, part of this industrial waste is re-fermented and distilled to produce different spirits or processed into fertilizers (Arvanitoyannis, Ladas, & Mavromatis, 2006;Baran, Ç ayci, Ku¨tu¨k, & Hartmann, 2001;Corte´s, Salgado, Rodrı´guez, & Domı´nguez, 2010;Ferrer et al, 2000;Ruggieri et al, 2009). However, disposing and incinerating substantial amounts of grape marc has become an important economic issue for producers as well as a significant environmental problem.…”

“…The stability and quality of stored grape marc for distillation has been evaluated in terms of different plastic and concrete containers (Corte´s et al, 2010), because spoilage is responsible for off-flavours in the final product (Da Porto, 2002). Dehydration is an adequate alternative to prevent deterioration providing simultaneously mass and volume reduction.…”

Advances in Distilled Beverages Authenticity and Quality Testing

“…Despite common laboratory methods used to test de-fermented marc quality, recent studies applied advanced methods. The quality of raw material subjected to fermentation, yeast specie and the inoculum amount, type and hygiene of the vessels [65], temperature and duration of the process are parameters intensively tested in the past years [20,26,28,66,67]. Yeast species used in fermentation have an important role in defining the final bouquet of the beverage, a gas-chromatography analysis proved [68].…”

“…When distillation columns are used, a significant increase of esters is observed, 20% more higher alcohols, less aldehyde (a decrease with 40%) and 10% less methanol, when compared to alembic distillation. Higher concentrations of methyl and ethyl acetates indicate the incorrect fractions separation (heads) during the distillation process [65]. Lactate ethyl (found in tails fraction), with unpleasant aroma, is considered a marker of the long fermented marc storage before distillation, when unwanted malolactic fermentation takes place.…”