Sémillon is a French white grape variety. Together with the vines sauvignon blanc and muscadelle, it is used to produce high-alcoholic white and liqueur wines such as Sauternes, Monbazillac or Loupiac. The sémillon is among the vines most prone to accept the noble rot from the Botrytis cinerea, a microscopic fungus that allows a natural concentration of grape sugars.