By Lenn Thompson, Executive Editor Disappointingly few rieslings made in the Hudson Valley from Finger Lakes fruit maintain the true character of the fruit's origin. There are many reasons why this could be, some unavoidable. Trucking fruit or juice from central New York to the Hudson Valley certainly isn't going to make for a pristine start to the winemaking process. That can't help. Add manipulative or extremely low-tech winemaking techniques (lack of temperature control during fermentation for instance) and it's easy to see why many rieslings made and bottled in the Hudson Valley under the "New York State" AVA can…