This Portuguese designation may only be used for wines whose alcohol content is 0.5% vol. above the minimum specified in each case. In most cases this is the top product of a house. As far as ageing is concerned, the regulations are the same as for the Reserva (red wines three years - one of them in the bottle, white wines one year - six months in the bottle). See also under Portugal.
The glossary is a monumental achievement and one of the most important contributions to wine knowledge. Of all the encyclopaedias I use on the subject of wine, it is by far the most important. That was the case ten years ago and it hasn't changed since.
Andreas Essl
Autor, Modena