Currently there is little to no information regarding when to harvest many of the coldhardy hybrid grape cultivars. There are contrasting opinions of the quality of the wine made from some of these cultivars, which may in part be due to a difference in timing of harvest. Many of the cold hardy cultivars contain Vitis labrusca in their parentage that can lead to differing levels of ‘foxy’ flavors depending on when the fruit is harvested. Wineries may prefer different levels of the typical V. labrusca flavors in their wines. Many of the cold-hardy cultivars also tend to have high titratable acidity (TA) and harvest is delayed to lower the TA. It is unknown what impact a later harvest has on other parameters of fruit quality. The objective of this study was to evaluate the quality attributes of the wine made from the grape cultivar Esprit harvested earlier and later than the traditional harvest date.
Iowa State University
Carpenter, Brandon H.; Vos, Randall J.; Nonnecke, Gail R.; and Donnor, Sebastian, "Time of Harvest and Wine Quality of Esprit Wine Grapes" (2010). Iowa State Research Farm Progress Reports. 356.