Vitis vinifera L. cultivars Müller-Thurgau, Muscat Ottonel, Gewürztraminer, and Kerner were studied for 1 year to document changes in fruit terpene levels from berry stage to free-run and press-juice stages. Substantial amounts of free volatile terpenes (FVTs) and potentially volatile terpenes (PVTs) were lost between berry and juice stages. PVTs were higher in press juices of `Gewürztraminer' and `Muscat Ottonel' than in free-run juices. In another experiment, juices from `Miiller-Thurgau', `Muscat Ottonel', `Kerner', `Optima', `Pearl of Csaba', and `Siegerrebe', harvested 10 to 20 days after a designated initial harvest date, contained higher FVTs and PVTs than initially. A third experiment with `Kerner', `Müller-Thurgau', `Optima', and `Siegerrebe' found highest FVTs and PVTs in juices from grapes subjected to skin contact compared with grapes crushed and immediately pressed. Sensory evaluation showed aroma differences between wines from free-run and press juices of `Miiller-Thurgau' and `Muscat Ottonel', aroma and flavor differences due to harvest date for all cultivars except `Pearl of Csaba', and aroma and flavor differences due to skin contact for `Siegerrebe'.
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