I recently purchased a bottle of vintage port from a producer that I had never heard of before: Borges Porto. It is a 1970 vintage according to the label, although nowhere on the label does it mention when it was bottled. I opened the bottle and was immediately surprised by how good the condition of the cork was; all of the vintage ports I have had in the past that were more than a couple decades old tended to have corks that were saturated to the point that they crumble apart. This cork however seemed to be brand new, despite it being a 49 year old vintage.
Anyways, when I began to transfer the port into the decanter I immediately noticed that the port itself was a deep, opaque brown color. It almost resembles prune juice, but somehow even more brown. This is not the translucent, amber brown color that you'd expect from a tawny; it's deep brown to the point that you can't see through it. It also bears no resemblance to any vintage or ruby port I've ever had, as there is virtually no trace of red/ruby coloring in the wine. The wine itself does not smell off or spoiled, and it doesn't taste spoiled either. I don't particularly like the taste; it's very thick and essentially tastes like a glass of cranberry juice. The alcohol is almost undetectable, which is also surprising, as most ports I've drank have that bite to them. If I were served this at a restaurant I would be sure that what the waiter/waitress brought me was not port.
So I'm curious to know what is going on here. Is anyone familiar with this brand of port? Is this a type of port that I have never discovered before? Has the port gone rotten? Or is there something else that I'm missing? I've never experienced anything like this, although like I said earlier I'm not a port expert. I have attached some pictures of the port itself as well as the bottle for reference.
I would definitely appreciate the thoughts of a community that is more knowledgeable about port than I am.
Thanks!