CAN YOU PLACE THAT WINE? AN EXPLORATION OF TRACE ELEMENT COMPOSITION OF WINE AND SOIL

In viticulture, many factors contribute to site individuality (terroir) including temperature, aspect, slope, bedrock geology, and soil chemistry. Though regional differences in wines have long been acknowledged, some experts discard the idea that inorganic element content contributes to these differences. Our hypothesis is that wine inherits elemental abundances from its terroir. This study presents trace element abundances such as K, Rb, Ca, Sr, Mn, Fe, Zn, Zr and Mo in soil substrata, vineyard vegetation, and pressed juice. In the Walla Walla Viticultural Area vineyards are planted on three different terroirs– basalt cobble loam, silt loam, and silt loam with underlying lacustrine substratum. Samples were acquired from one representative Syrah vineyard from each terroir. Chemical analyses for 9 soil samples from each terroir and 36 samples from each vineyard's cultivar were obtained with a Portable X-ray Fluorescence spectrometer. Chemical analyses of the grape juice samples were obtained with an ICP-MS. Concentrations of Ca and Fe are a factor of 2 and Zn and Mn are a factor of 1.5 higher in the basalt cobble loam relative to other substrata. The silt loam sites have lower concentrations of Fe, Ca, K, Zn, and Mn and also retain more water than the silt loam with lacustrine substratum sites, possibly indicating leaching of elements in the silt loam site. Initial plant data show that these soil differences are broadly incorporated in plant stems, roots and leaves.