Madeira is a fortified wine produced from native Portuguese grapes grown exclusively on the Portuguese island of Madeira. The base wine is made, fortified with grape spirit, and readied for maturation. Unto this point, the production is much the same as for the Ports from the Douro Valley. However, Madeira is unique for the slow-cooking process that follows. Historically, the fortified wines were filled into oak barrels, loaded onto ships and sailed through the tropics; the traditional commercial process involves positioning casks within warehouses in direct sunlight to maximise heat exposure. This slow-heating releases the sweet tannins from the wood into the wine, resulting in a distinctive stewed-fruit and caramel character.
There are 4 traditional "Noble" grapes of Madeira, each producing distinct wines with particular levels of sweetness:
- Sercial - Dry
- Verdelho - Off-dry
- Bual / Boal - Semi-sweet
- Malvasia / Malmsey - sweet
However, the most widely planted grape variety is Tinta Negra. Most basic Madeiras - and those which do not specify themselves as containing any of the noble grapes - are likely to be produced using Tinta Negra.
Barbeito, Blandy's, Cossart Gordon, Henriques & Henriques (H&H), and Justino's are the most well known producers.