Final answer:
Sweet style Madeira wine is made from Malvasia, Bual, and Terrantez grapes, which contribute to its full-bodied, rich, and medium-sweet profiles.
Step-by-step explanation:
The three grapes used to make sweet style of fortified Madeira are Malvasia (also known as Malmsey), Bual (or Boal), and Terrantez. Madeira is a fortified wine from the Portuguese archipelago of Madeira. Malvasia grapes produce a richly sweet and full-bodied wine, while Bual grapes result in a slightly less sweet but still rich wine.
Terrantez is quite rare and produces a delicate, medium-sweet style of Madeira. Due to its fortification process and aging, Madeira has a unique flavor profile and is celebrated for its longevity and resilience.