By Lenn Thompson, Executive Editor Morten Hallgren, winemaker at Ravines Wine Cellars, makes dry wines and dry riesling… and that's it. That's unique in a region where just about every winery has at least two rieslings — "Dry" and "Semi-Dry" — and often more. Having a portfolio without at least one sweeter wine — 1% residual sugar is as high as it gets at Ravines — is somewhat risky in a region visited by throngs of sweet wine lovers. Most wineries stock at least one or two wines "for the masses" but Morten and his wife Lisa seem to be…