(RFI) - American wine guru Robert Parker, whose ratings could make or break Bordeaux vintages for the past 38 years, is to turn his power over to a successor on Sunday, his magazine announced.

It will be the end of an era for the 68-year-old oenologist, who has however been retiring in stages, in 2014 leaving his British successor Neal Martin to rate "en primeurs" (futures) while continuing to evaluate top Bordeaux vintages.

It is this prestigious baton that will pass to Martin on Sunday, while Parker holds on to his role scoring northern California wines, such as those of the Napa and Sonoma valleys.

Parker's extraordinary nose has earned plaudits from the likes of former French president Jacques Chirac, who said he was "the most followed and influential critic for French wines in the entire world."

Parker will also stay on as president of Wine Advocate, even though he sold the market-moving magazine to a Singapore consortium in 2012.

His parting Bordeaux evaluation will be the top score on his vaunted 100-point scale that he awarded recently to a Pape Clement 2009, a Graves "grand cru" created by the millionaire philanthropist Bernard Magrez.