2 METHODS OF PORT VINIFICATION - A COMPARISON OF CHANGES DURING FERMENTATION AND OF CHARACTERISTICS OF THE WINES

A traditional lagar (stone trough) fermentation, with crushing by trea ding, was compared with fermentation in a tank with mechanical crushin g. For the tank fermentation, pigment extraction was increased by pump ing juice drawn from the bottom of the tank through a spray head at th e top of the tank. Yeast growth, sugar depletion, ethanol formation, a nd changes in amino acid composition were monitored during the two kin ds of fermentation. No marked differences in these fermentation charac teristics were found between the lager and tank systems. The effect on the quality of the end product was assessed by color analysis and sen sory assessments of the wine during maturation. The results showed ini tial differences in pigment extraction and significant differences in sensory attributes; but as the wine matured over three years, this dif ference in sensory quality became insignificant. Hence, the sensory qu ality of the finished wines did not depend on the method of production .