Experimental vinification of withered grapes of Vitis vinifera “Muscat of Alexandria”

Abstract

AIM – The objective of the present work is to investigate wine produced from dehydrated grapes and vinified according to classical Roman manuals.

METHODS: Locally produced Muscat of Alexandria’s grapes were used for the sweet wine production, grown in the experimental vineyard of Instituto Superior de Agronomia (Lisbon, Portugal). The grapes were harvested manually slightly over-ripe and subjected to greenhouse drying. After 7-10 days dried grapes were transported to an experimental winery for various operations (e.g., grape weighing, sorting, crushing/destemming). Several maceration protocols were used comprising the addition of saltwater and white wine to whole bunches or destemmed grapes. Fermentation was conducted with the addition of commercial yeast. The standard physico-chemical parameters of wines were determined according to the OIV standards.

RESULTS: The results showed that all the samples had higher alcoholic content and residual sugar, ranging between 14.7 and 17 (% v/v), and 0.8 g/l to 18 g/l, respectively. Volatile acidity was less than 1 g/l in all wines, except in that obtained from withered grapes alone, probably due to stuck fermentations. In some of the wines, after fermentation, mousiness was clearly perceived.

CONCLUSIONS:

The obtained wines showed that it is possible to obtain acceptable products closely following the relevant protocols described in classical Roman manuals. The main problem was the detection of the mousy off-flavour that can be associated with the absence of sulphur dioxide addition to the musts before fermentation.