Combine clam juice and wine in heavy small non-reactive saucepan. Bring the liquid to a boil until reduced to 1/3 cup, about 9 minutes. Reduce heat to medium.
Whisk in creme fraîche. Boil until reduced to 1 cup which should take about 5 minutes. Remove the sauce from the heat. Stir in the dill. Season with salt and pepper.