In 1973 Winroth enrolled in a tasting course for wine growers given by Professor Émile Peynaud at the University of Bordeaux. He stayed with M. Wainstein, a wine broker. After a full day of intense classes and wine-tastings, Wainstein would subject him to a blind tasting of about ten wines. Exhausted, Winroth felt he could not distinguish a Beaujolais from a Bordeaux wine. Finally, the last evening, the miracle occurred: he identified each wine correctly, and even picked out the "pirate", a foreign wine. He said that evening gave him almost as much pleasure as the certificate signed by Professor Peynaud.