A. J. Adam takes us to Dhron, just off the much-beaten path of the Mosel river. Dhron is named for a river that flows into the Mosel. Its steep, slatey vineyards form the tributary's northern bank. The sites are steeper and at higher altitude than most of Mosel. The wines are a little wispier and saltier. The fruit is cooler and whiter. Adam is Dhron's undisputed star. He makes extraordinary dry Rieslings and Kabinetts from Hofberg, the top site in Dhron.