Book Description

It is often said that high quality grapes must be used in order to create high quality wines. This production begins in the vineyard and is impacted by viticultural and environmental conditions that may or may not be able to be controlled. Weather conditions are among these uncontrollable factors, and the influence of weather conditions on final grape and wine quality has been the subject of investigation in both research and industry for many years. Many studies have determined that factors such as rainfall, sunlight exposure, and temperature play an important role in the development of phenolic and aromatic compounds and their precursors in berries, which ultimately affects wine aroma, taste, and flavor. Examination of weather conditions and climate in wine regions have been the subject of studies not only to understand impacts on wine quality attributes, but also to determine if regional trends exist for particular areas. The concept of regionality, or the particular style of wine that a growing region produces, is a new area of study for the Eastern United States, including Pennsylvania, which is the focus of this study. Determining regional characteristics can assist growers in predicting the quality of grapes before harvest and can also identify viticultural and sensory factors that can improve marketing strategies to wine consumers. Grüner Veltliner (Vitis vinifera; GV), an Austrian grape variety, is a relatively new grape to wine growers and producers in the northeast United States including Pennsylvania (PA). While climatic conditions are favorable to its growth, the PA wine industry is still becoming familiar with the varietal characteristics of GV grown and produced across the state. The aim of this study was to characterize the chemical and sensory factors that drive regional differences in PA GV wines through a controlled winemaking study. GV grapes were harvested from experimental sites in four PA growing regions over two vintages. A total of 9 sites were chosen in order to capture climate variability of the growing regions and to be representative of the various regions that currently grow GV in PA -- two in the Northwest (NW), one in the North Central region (NC), one in the Northeast (NE), and five in the Southeast region (SE). Weather data was collected from each site during both growing seasons as well. Wines were vinified using a standard vinification method to eliminate the influence of winemaking style on samples. Chemical analysis included headspace solid phase microextraction gas chromatography mass spectrometry (HS-SPME-GC-MS), high performance liquid chromatography (HPLC), and color analysis using CIE-Lab. Descriptive analysis was used to evaluate aroma, taste, mouthfeel, and flavor intensities in wines vinified from each experimental site. Finally, Pearson's correlation was used to examine if any relationships existed between sensory and instrumental variables. Two descriptive analysis panels (one for each year of study) found significant differences (p