Niepoort and late-bottled longevity

Niepoort LBV ports, made in the style once designated 'traditional', ie the produce of a single year, bottled 4-6 years after harvest and unfiltered, are unusual in their capacity for long ageing, as rather whimsically demonstrated by Dirk Niepoort at a tasting in London of eight vintages, from 1975 to 2009. This is definitely not the style of LBV, probably the most common today, where much of the wine's character may be stripped out by fining and filtration.

I say whimsically not because Dirk is a whimsical winemaker, far from it. In fact he seems methodical and patient when he...