Impact of the maturity and the duration of maceration on phenolic composition and sensorial quality of Divico wines

Abstract

Following its approval in 2013 by Agroscope, Divico became the first interspecific grape variety in Switzerland with high resistance to downy mildew (Plasmopara viticola) and grey rot (Botrytis cinerea), and medium resistance to powdery mildew (Uncinula nectator). Extremely riche in color, Divico grapes showed great enological potential to different styles of wine. Quickly, many wine growers were interested in planting this promising variety. Many of its potential are to be explored in the coming years.

The objective of this study is to evaluate the impact of the harvest date and the duration of maceration on phenolic composition and sensorial quality of Divico red wines. During two consecutive vintages, 2019 and 2020, Divico grapes grown on two terroirs in Switzerland, Pully and Leytron, were harvested at commercial maturity (1st maturity) and 2-3 weeks later (2nd maturity). Two wine making processes with 6 days and 13 days maceration duration were applied to the same grapes. Grape and wine phenolic composition analyses were conducted during maturation, during wine making and after bottling. Sensorial analyses were conducted only after bottling.

Divico wines obtained were riche in phenolic compounds. Total polyphenol index with DO280nm were higher than 100. The concentrations of proanthocyanidins in obtained Divico wines varies from 3-5 g/L. 13 days maceration wines presented higher concentration of proanthocyanidins due to extra extraction of seed tannins. The values for anthocyanins were close to 3 g/L. Wines obtained with the 2nd maturity grapes and with 6 days maceration were preferred for higher fruity intensity, less acidity, more velvet tannins and better mouth equilibrium. 13 days maceration wines presented more aggressive tannins and bitterness in mouth. These results indicated that Divico grapes probably didn’t reach the optimum seed phenolic maturity even for the 2nd harvest day. Moreover, aroma management during prolonged maceration should be mastered if this practice is desired.