Madeira wines that not have the varietal are usually made with "Tinta Negra Mole". This is the "poor cousin" grape they use to make cheap Madeiras. I think is deserves a try if you're in the mood. It will be good for the beginning of knowledge of these great wines
I am here to protect the virtue of the NM grape!
Tinta Negra Mole or "soft black grape", which now can only be called,
Negra Mole (as per IVM regulations) has been unfairly categorized by many journalists and authors and dare I say, mistakenly. There is no question that it is the most widely planted grape on the island and is somewhere close to 80% of all grapes harvested in Madeira.
However, the constant maligning of the Negra Mole grape is done with either malice but more likely, a lack of knowledge, as to the truth about this grape. According to Ricardo de Freitas, Managing Director of Barbeito, the Negra Mole is a descendant of the Pinot Noir grape. It has evolved though and today has the unique ability to emulate the four noble grapes of Madeira, (Sercial, Verdelho, Boal and Malvasia) especially when planted in close proximity to any of these. It is one of only two grapes used in Madeira production that are not white, the other being the extinct Bastardo (also occasionally used in the Douro for Port production).
So, although the Negra Mole might often wind up in the less expensive cuvees of the island, like Rainwater or 3 year old Madeiras, it has long been used as a complement for the noble grapes in small quantities for more upscale categories, but its name does not find its way onto the labels of finished product.
Few will come to the fore to defend the reputation of the Negra Mole grape, because over the course of history it has been misunderstood and used as a scape goat, even in some prominent writings on the subject. But the facts are known by the producers and although some use almost none of the NM, others consider it a requisite grape for their ongoing production.
(I'm serious about that...drives me nuts, but as long as she's happy)