Garrafeira is a term used to describe a wine of denominacion status, usually from an exceptional year.
Red wines must be aged for at least 30 months before release, at least 12 of which must be in bottle.
White and Rosé wines must be aged for at least 12 months, at least 6 of which must be in bottle.
(Source: Sogrape -
https://www.sograpevinhos.com/enciclopedia/wineexpert/faq)