Grape phenolic compounds, which are secondary metabolites that develop in grapes during ripening are associated with grape and wine quality. 

The phenolic synthesis and accumulation in grapes and the resulting grape phenolic content are influenced by terroir.  In particular, the vineyard soil is a key terroir element contributing a substantial control on the grapevine nutritional and water status; thus, the properties of vineyard soils influence the quality of the grapes and sensory attributes of the wine produced in that vineyard. 

This study presents an evaluation of the relationships between soil characteristics (parent material, depth, texture, chemistry, water holding capacity, and organic matter) and the classes and concentrations of phenolic compounds developed in syrah grapes from vineyards located in the four different terroirs of Walla Walla Valley American Viticultural Area, exploring the link between grape quality and terroir in a step toward quantifying and further deciphering the terroir effect. 

Keywords: Walla Walla Valley, Terroir, Phenolic Compounds, Syrah Grapes, Soil Properties

Paper presented at the XI International Terroir Congress, July 2016, McMinnville, Oregon (USA).

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