What makes reds age well?

Old age is complicated, for wines as for people. Should old wines that have weathered the chemical interactions of their years in bottle automatically be worthy of respect? Is longevity the prerogative of finer wines, or is it their hallmark? Most difficult of all, what enables a wine to age well, and is 21st-century winemaking – should such a thing exist – conducive to this process?

These are the sorts of questions that have irritated my thoughts over the last few days, prompted afresh by my first experience of judging in the Old Mutual Trophy Wine Show in Paarl...