Since 1980, the major thrust of my research program has been the impact of viticultural practices on grape and wine composition and quality.
Viticultural practices have a great influence on the quality of wine grapes and wines.
Problems during vinification can sometimes be averted by altering viticultural production techniques. Altering wine quality in the field by altering grape composition is preferable since correcting problems in the winery means additional processing steps during vinification. The more wine is handled during processing the greater the chances that quality will be adversely affected. In Washington, V. vinifera production must contend with a unique combination of characteristics - very cold winters, very low rainfall, relatively short growing season, high light intensity and warm to hot temperatures in the summer, and wide diurnal temperature fluctuations particularly during the summer and fall during fruit development and ripening. Due to these unique characteristics, research conducted in other regions is not necessarily applicable.