As we enter a new year, it seems appropriate to consider wine and time, and Riesling is one of the grape varieties that can benefit most from seriously long ageing - much longer than most Chardonnays, for instance. In fact I'd say that a top-quality Riesling's ageing curve is remarkably similar to that of a fine Cabernet. (Discuss...) Here are notes on the fourth and last of the tastings at last November's International Riesling Symposium, a collection of nearly two dozen mature and maturing Rieslings. (J J Prüm wines seem to need decades rather than years in bottle.) The oldest of the wines was one from the great 1959...