By Lenn Thompson, Founder and Publisher If the Napa Valley is cabernet sauvignon country and Long Island is the land of merlot (and cabernet franc), the Finger Lakes region is definitely the U.S. region where riesling shines brightest. The deep, narrow lakes that give the region its name gather and hold a significant amount of heat in the warm summer season, extending the grape-growing season just long enough to ripen grapes as well as protect vineyards against potentially catastrophic early frosts. Recently, James Molesworth, on WineSpectator.com rated several Finger Lakes Rieslings well — in the high 80s —…