Nothing sends me more regularly back to my reference books than the need to understand grape varieties. Over the last decade or more, though, the insights of genetics have reshaped the varietal horizon, and made the old books redundant. We’ve all, consequently, become a little nervous about definitive varietal pronouncements, in case the ground had moved under our feet. What if Viognier turned out to be genetically identical to Fiano, or Merlot proved to be Sangiovese’s aunt? And what do we call Zinfandel this week?

That’s why an almost audible sigh of relief will go up across the wine world on Thursday: at last the wine world can lay its hands on the reference grammar we all need. Wine Grapes by Jancis Robinson MW, Julia Harding MW and Dr José Vouillamoz (all 2.66 kg of it) is a magnificent achievement: colossally informative, illuminating and intriguing. No one but Jancis Robinson could have marshalled such a project, galvanizing and coordinating the efforts of the international wine community. The genetic researches of Dr Vouillamoz and his colleagues provide the book’s wow factor, while the painstaking scrupulousness of Julia Harding surely lies behind its seamless grafting of scholarship and academic rigour to informative, descriptive prose.

Once I’d ripped the cellophane off the book’s fabric-coated box, I couldn’t resist road-testing it with a couple of... read on