马德拉酒
Boal is a name given to several varieties of grape cultivated in Portugal, notably in the production of medium-rich fortified wines from Madeira Island. On many wine labels of Madeira wine, the variety's name is anglicized as Bual. Madeira from Bual is typically less sweet than that from Malmsey, but more sweet than Sercial or Verdelho. The vines are also common in Portugal and Spain, where the fruit is used in the same way for fortified wines.