At least as recently as the first decade of the aughts, at Beaucastel, they claimed to use all allowable grapes, red and white, in their red wine. The amounts were miniscule but not non-existent. As proof that this was traditional at the domaine, they had on the wall a photo taken in the early 20th century of a large batch of grapes about to be vinified into the red wine and one could see quite clearly, scattered here and there among th red grapes, some white ones as well.Maybe they’ve changed in the past few years, but I don’t think so as it would have been at least noticeable news. If anything, the practice has increased in recent years. I’ve read, for instance, that Pegau has been using white grapes in its red blend for some time, though I will yield to correction from Dan Kravitz about this.
Actually, if the OP or others peruses that page, you can find blends for a large percentage of wines tasted for 2017. You can find similar info for 2016 on the site as well. I do not have the same depth of info for 2018, as those wines were all tasted at home.
I am not sure if these wines have already been mentioned in this thread, but it is interesting to note that there are at least 3 Chateauneuf du Pape’s that are 100% Syrah; Maravilhas Espirito, La Mereuille Cuvee d’ Aure, and St. Paul L’Insolite.
There are also at least 3 wines from 100% Mourvedre; Semelles Pur Mourvedre, Mas de Boislauzon Tintot and Chante Perdrix, Henri Perges.
You can find several other non Grenache dominated blends all over the appellation as well.
As I pointed out in post #18, the Beaucastel website refers to vinifying all 13 varieties separately for the red, so, unless they toss some out or downgrade them, it seems they are still using all 13.
Domaine Les Cailloux occasionally (1994, 1995, 2000?) produces an all-Syrah Châteauneuf-du-Pape bottling called Boréale, but the 1995 was affected by something, perhaps a spoilage yeast, and were undrinkable; my two bottles tasted like orange juice that had gone bad.