Blanc de Noirs question

Here is what Clive Coates had to say in a book of his:

"Blanc de Noirs

Blanc de Noirs, literally 'white of blacks', is a Champagne made entirely from either or both Pinot Noir and Pinot Meunier. There are very few of these wines. Bollinger produces a delicious but very, very expensive wine from a small plot of vieilles vignes fran=E7aises (ungrafted vines). The colour is golden, rather than straw-yellow and the wine is full-bodied, intensely flavoured, and very rich but not sweet: certainly a Champagne for food rather than for drinking as an aperitif."

Coates usually is right concerning French wines. If the wine is any kind of Champagne, it must contain only allowed grapes. However I do not know if French law would allow a certain small amount of Chardonnay, or if the complete exclusion of Chardonnay is just a custom.

When it comes to other sparkling wines, there might be variation from country to country and for states or regions within countries. Several California wines have been labeled Blanc de Noirs. I recall that, in the past, many New York state "champagnes" were made from native and hybrid grapes, so who knows what rules and customs would apply in such a case. Also many countries outside of Europe likely have their own rules and customs. I suspect that you could find some state in the US or some country where you could make a wine labeled "champagne" blanc de noirs from Concord table grapes!