Jim Clendenen of Au Bon Climat, at his loquacious best and with plans to celebrate his son's birthday in Piemonte on the way back to the US, strung observation and anecdote into a positive river of consciousness at a tasting in London this summer past, organised by London wine merchant   Roberson . It will surprise no one who has ever come within a few hundred yards of him to know that he barely drew breath as he talked about his wines and his approach to winemaking: 'Ten minutes is all you need to learn the science in winemaking. Artistic and agricultural aspects are best learnt on the job.' (He was a student of law.) Whereas once...