The quality of sweet wines (liqueur-like): comparison of various techniques of concentration | Qualite des vins doux (liquoreux): comparaison de diverses techniques d'elaboration
Cuenat, Ph. | Bregy, Ch.-A. | Lorenzini, F. | Viret, O.(Agroscope RAC Changins, Station federale de recherches agronomiques, Nyon (Switzerland))
Swiss sweet wines are traditionally elaborated from late harvested grape. The success of this process strongly depends on the weather conditions. Over-ripening of the grapes in the vineyard (late grape harvest), self-enrichment of must by evaporation, cryoextraction and passerillage (raisining) under controlled conditions were compared over three different years. Among the techniques of over-ripening lowest population of acetic and lactic acid bacterias is recorded in the late grape harvest proceed and in the passerillage carried out at high temperature. The malic acid content of grape berries varies according to the temperature of the passerillage. The self-enrichment of the musts gives the wines with the highest levels in acidity and volatile acidity and with the lowest in sulphur dioxide. The compared techniques show significant differences both for sensory quality and chemical composition of sweet wines. The passerillage, carried out under adapted conditions of temperature, gives wines with equivalent quality to those issued from late vintage. The combination between over-ripening and cryoextraction also gives interesting sensory results.
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