Isn’t red Riesling just a mutation of white Riesling and hence still a white wine grape?
Very interesting question but the answer is no.
Most grape cultivars get divided into red and white because of the presence or absence of anthocyanin in the berry skin. But that mutation has been found to be a genetic mutation where the gene that activates anthocyanin isn’t transcribed in white berries. So most white grapes are mutations of red, and there’s some idea that red Riesling may be the original, which would be consistent with much of the other mutations.
Since Pinot Blanc is a mutation of Pinot Noir, is it still a red grape? No. Or is Pinot Gris? Again, no.
Or since nobody knows which came first, what about Pinot Meunier? Or Pinot Liébault or even Pinot Teinturier, which has red flesh as well as red skin? No way it could be a white grape.
Then there is Tempranillo blanco. And Garnacha blanca.
And Merlot Gris, which is a mutation, as opposed to Merlot Blanc, which is a related grape but not a clone.
Then there is Malian, which I believe is a sport of Cabernet Sauvignon that isn’t completely white, akin to Pinot Gris from Pinot Noir, and then Shalistin, which is a further mutation that is white and is more akin to Pinot Blanc.
Something like Roter Veltliner is different because that and Gruner Veltliner aren’t mutations but are different grapes entirely.
You get these mutations in flowers like roses all the time and bright young things apply for plant patents on them. They get their own names and they’re as originals.
Same with the wine grapes.
The mutations are their own thing. If it’s a mutation that turns a white grape red, it’s a red grape, and vice versa.
