South Africa is a nation reinventing itself. Its wine industry is doing likewise, and one challenge it faces is to meet the future without abandoning the best of what has come before. It's a balancing act, and a difficult one. South Africa is making better wines than ever, thanks in part to new plantings of international blue-chips such as Cabernet Sauvignon and Syrah. Yet much of its potential is rooted in its past, still hidden in old-vine vineyards. And much of that valuable history is now at risk. Wine Spectator's James Molesworth explains.