In 1938, the estate was bought by Professor Jean Ribereau-Gayon who was to become the forefather of modern oenology. The story begins around 1850 when the Great French Wine Blight began to destroy French vineyards and as a consequence of this national tragedy which destroyed 40% of French wines between 1850 and 1865 the great chemists of the time turned their attention to wine, including Louis Pasteur. Professor Ribereau-Gayon’s grandfather, Ulysse Ribereau-Gayon was a pupil of Louis Pasteur and invented “Bouillie Bordelaise” or Bordeaux mixture which combines copper, sulphites and lime and is still used today as a fungicide to protect the vineyards of Bordeaux.

Beginning with his important papers in the 1930’s, Jean Ribereau continued his family’s important role in the history of oenology. And the vineyard and wine cellars of Les Conseillans were to play as supporting part. After planting the vineyard in 1938, Professor Ribereau-Gayon set up an experimental cellar and built a chemistry laboratory in a small utility room off the kitchen. In the old vat room, which is now the Chateau’s wine-tasting room, Professor Ribereau-Gayon discovered the chemistry of malolactic fermentation, which completed the basic science required for modern oenology.
In 1949, Professor Ribereau-Gayon and his colleague Emile Peynaud founded the Bordeaux Institute of Oenology which continues to produce the foremost oneologists in the world. For the rest of his life, Professor Ribereau-Gayon continued his teaching and his study of the vineyard and its wines. He remained very attached to Chateau Les Conseillans until his death in 1991.