A Broad Analysis of Vineyard Soils, Grape Juice and Wine Chemistry
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Portland State University PDXScholar Dissertations and Theses Dissertations and Theses Spring 6-2-2016 The Terroir of Pinot Noir Wine in the Willamette Valley, Oregon : A Broad Analysis of Vineyard Soils, Grape Juice and Wine Chemistry Kathryn Nora Barnard Portland State University Follow this and additional works at: https://pdxscholar.library.pdx.edu/open_access_etds Part of the Environmental Sciences Commons, Geology Commons, Soil Science Commons, and the Viticulture and Oenology Commons Let us know how access to this document benefits ou.y Recommended Citation Barnard, Kathryn Nora, "The Terroir of Pinot Noir Wine in the Willamette Valley, Oregon : A Broad Analysis of Vineyard Soils, Grape Juice and Wine Chemistry" (2016). Dissertations and Theses. Paper 2941. https://doi.org/10.15760/etd.2936 This Dissertation is brought to you for free and open access. It has been accepted for inclusion in Dissertations and Theses by an authorized administrator of PDXScholar. Please contact us if we can make this document more accessible: [email protected]. The Terroir of Pinot Noir Wine in the Willamette Valley, Oregon – A Broad Analysis of Vineyard Soils, Grape Juice and Wine Chemistry by Kathryn Nora Barnard A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Environmental Sciences and Resources: Geology Dissertation Committee: Scott F. Burns, Chair Robert B. Perkins Andrew Fountain Martin LaFrenz Teresa Bulman Portland State University 2016 © 2016 Kathryn Nora Barnard Abstract Terroir is determined by a combination of factors in the vineyard including the grape varietal, geology and soil, soil hydrology, physiography, and climate. Although most studies have examined regional differences in wine flavors and associated provenance of wine based on chemistry, few have examined the chemistry of the soil and the ability to trace that chemistry to grape juice and, finally, to the wine. This dissertation examines what soil physical and chemical differences specific to this region might influence grape juice chemistry and wine chemistry. Wine-grapes in the Willamette Valley, Oregon, are grown on three major soil parent materials: volcanic, marine sediments, and loess/volcanic. Winemakers have observed differences in the flavor of Pinot Noir wine made from grapes grown on these different parent materials. This dissertation examines differences in the soil properties and elemental chemistry of the soil parent materials at various vineyards to document their effect on wine chemistry as a step towards understanding differences in flavor. All aspects of the terroir are controlled by carefully selecting vineyards with similar exposure and elevation, the same grape varietal and wine making techniques, and only the soils vary. The hypothesis is that the chemistry of the grape juice and wine reflect the soil in which the grapes were grown and that the three parent materials have soils that can be distinguished by their physical and chemical characteristics. i Soil pits were excavated in 20 vineyards, soil properties were described in the field, and soil samples were later analyzed in the laboratory particle size, organic matter, color, pH, cation exchange capacity (ammonium acetate method), clay mineralogy (x-ray diffraction), and elemental chemistry (ICP-MS/AES). X-ray fluorescence was used to examine the pisolites. ICP-MS/AES was used for elemental analysis of grape juice and wines produced from these vineyards. Principal component analysis was used to compare soil physical and chemical characteristics, grape juice and wine chemistry. The physical characteristics of soils from all the three parent materials indicate: they are old (>50,000 years) based on their high clay content, low cation exchange capacity, red colors, and high Fe and Al content. These features indicate enough time has passed to reduce organic matter and other cations at depth, leave behind insoluble Fe and Al, and develop pedogenic clays. In my study region, volcanic and marine sediment soils are more developed with slightly lower acidity than the loess/volcanic soils. A new finding for this region is the presence of pisolites (Fe/Mg concretions) in the volcanic and the loess/volcanic soils, but absent in the marine sediment soils. Winemakers hypothesized that pisolites were present only in loess soils and influenced wine flavor in some way. Volcanic soils have the highest P, S, Fe, Co, Mn, and V concentrations and the lowest As and Sr values. Marine sediment soils have higher Cl and Sr and lower P, Co, Mn, Ba, and V concentrations than volcanic soils. Loess soils have the highest values of ii K and Mg and are similar to volcanic soils with higher P and V values and similar to marine sediment soils with higher Sr values. The main elements found to be significant in determining one parent material from another are V and Mn (volcanic soils), Mg and K (loess soils), and Sr (marine sediment or loess soils). Sr is slightly higher in grape juice and wine from vines grown on marine sediment parent material compared to volcanic and loess parent material, whereas Mn is higher in the juice and wine from grapes grown in volcanic parent material. P, S, Fe, Co, V, Cl, Ba, Mg, and K did not maintain their relative concentration levels from soil to grape juice to wine. The principal component analysis shows that soil and wine chemistry differs between parent material, but is inconclusive for grape juice chemistry. iii Dedication To Seth D. Boss 1983-2010 Knowing that you and I will always have a bond as strong as the bows we climbed, as constant as the flowing creeks we crossed, as deep as the waters we navigated, and as eternal as the darkness in which we both desperately grasped for the light, I surrender this effort to your memory. Your death, as much as your life, gave me the courage to discover my brokenness and begin the arduous journey of healing and growth. Without you I would have surely fallen and your spirit would not have been there to help me up. This work is dedicated to you, Seth, my best friend and partner in crime in this life and the next. RIP iv Acknowledgements I would like to give my deepest gratitude to my advisor Dr. Scott F. Burns. His support, enthusiasm, and undying optimism are the backbone of my success. I would like to thank my committee for comment and criticism that encouraged my reflection throughout this process: Dr. Robert B. Perkins, Dr. Andrew Fountain, Dr. Martin LaFrenz, and Dr. Teresa Bulman. Thanks to other professors and classmates who helped me with my dissertation. I thank my mother for encouraging and supporting me throughout this long and difficult process. There is nothing more motivating than knowing someone is proud of you. I thank the wineries and vineyards in the Willamette Valley for allowing access and having patience for results they are eager to utilize: Elk Cove Vineyards, Willakenzie Estate Winery, Chehalem, Lange Estate Winery and Vineyards, Rex Hill, and Ken Wright Cellars. Many thanks to APEX Laboratories, Dr. Reed Glasmann of Willamette Geological Services, Oregon State University, and Washington State University for their lab analyses. I am grateful for the support of the Erath Family Foundation for funding much of the outside lab work, and to the NSF Cascades to Coast GK-12 Program for financial support and connecting me to many in the Portland community with whom I can share my knowledge and grow. I also want to thank Cooper Mountain Vineyards, Gilles de Domingo, Barbara Gross, and Dr. Robert Gross for their support, knowledge, and a love for organic and biodynamic farming. v Table of Contents Abstract ................................................................................................................................ i Dedication .......................................................................................................................... iv Acknowledgements ............................................................................................................. v List of Tables .................................................................................................................... xii List of Figures ................................................................................................................. xxii Chapter One – Introduction ................................................................................................ 1 Objective of This Study .......................................................................................... 5 Study Area .............................................................................................................. 7 Limitations ............................................................................................................ 10 Chapter Two – Background .............................................................................................. 12 Implications of Research....................................................................................... 12 Terroir ................................................................................................................... 14 Terroir and Soils ............................................................................................ 18 Willamette Valley Geology ........................................................................... 20 Soils and Geology.......................................................................................... 23 Climate .........................................................................................................