March 1, 2016
Sémillon: For exceptional Sweet Bordeaux wines
Louis Bordenave, engineer at the Institute of Sciences of the Vine and Wine, says that Semillon is the best grape variety to create great sweet Bordeaux wines.
Sweet Bordeaux‘s perfection simply comes from the nature surrounding. While the winemaker brings his expertise and sensitivity, he also needs a suitable weather, neither too dry nor too humid, a suitable soil with clay and limestone or gravel, an ideal location on good hills… But most important, he must have the best grape variety: Sémillon. It’s this variety, mainly found in the Sweet Bordeaux area, Sauvignon and also to a lesser extent Muscadelle, which bring this great taste. The Sémillon, white grape that can be classified in old vines, is in Bordeaux better than anywhere else. It is used to bring softness and taste to Bordeaux’s sweet white wines. « It’s difficult to date the arrival of Sémillon in the Bordeaux area, but we know that it’s a native grape variety. It appeared, several centuries ago in the Sauternes region, as the result of a long selection. It’s obvious that its cradle is the best place to give an excellent sweet wine « says Louis Bordenave, engineer specialized in Bordeaux grape varieties at the Institute of Vine and Wines Sciences (French National Institute for Agricultural Research). « The Sémillon is also probably the single variety native of Bordeaux among white and red wines together » says the specialist.
The Botrytis cinerea
Here is something that anchors the Sémillon in a unique soil. A grape which naturally allows the creation of unique sweet white wines. It’s not by chance that the delicious grape can reach its peak in the Sauternes region, Barsac, Sainte-Croix-du-Mont, Loupiac or Cérons. « The Botrytis cinerea, the fungus also known as noble rot, which enables with the Sémillon, to obtain a perfect juice, well balanced between sugar and alcohol, can develop favorably, ie without degrading grapes, under the conditions provided by this particular type of soil « says Louis Bordenave. Sauternes, Sainte-Croix-du-Mont and the Garonne valley, in fact, provide an ideal microclimate for growing and harvesting Sémillon grape. Thanks to the morning fog favored by the Ciron valley, the dew, during the late harvest, allows the Botrytis’ development. Then the afternoon sun inhibits moisture. « The late season sun in Bordeaux removes the excess water, it allows the grape’s pulp to concentrate, to candy hence creating interesting flavors » says the engineer. Sémillon is the only grape variety that can not be emptied of its grains due to the fungus. The grape becomes saturated with natural sugar. « It’s this peculiarity in Sémillon, which provides these great flavors to Sauternes! » notes Louis Bordenave.
Small quantity, great quality
In order not to dilute the wine, to preserve sugars, alcohol and Sémillon‘s unique aromas, the vine size is kept short. Because of the inevitable withering of grapes due to the noble rot, Sémillon is characterized by rather low yields ». At Château d’Yquem for example, Sauternes’ greatest wines, it’s said that they produce only one glass of wine per vine! » explains Louis Bordenave. This scarcity also gives its value to an exceptional variety for exceptionnal sweet and mellow white wine.