Q. CMOS 8.61 says that words derived from proper nouns like “champagne” are often lowercased when used with a nonliteral meaning. What does “nonliteral” mean when it comes to sparkling wine?
A. The word “champagne” with a lowercase c refers to sparkling wine of any kind, a generic use that is widely accepted; “Champagne” with a capital C, on the other hand, is a proper noun. It literally refers to a specific region in France known for its sparkling wine—or, thanks to industry advocacy, to sparkling wine from that region.
Lowercase “champagne” might be appropriate in a novel or a story—or any casual prose—when the origin of the sparkling wine is unknown or unimportant. If, however, you are writing something like a research paper or a press release, you will want to maintain a clear distinction: write “Champagne” with a capital C to refer to a sparkling wine that it is literally a product of Champagne but “sparkling wine” when it is not (or not necessarily).
The word “Champagne” is closely guarded, but the strictures apply mainly to how the industry labels and markets its products. “Scotch whisky” is similarly protected, and in industry usage, it gets a capital W to go with its capital S. Other such terms tend to be looser—or more general. One example is “swiss cheese”—in which the lowercase s suggests the stuff with the holes, not cheese that’s literally from Switzerland (which might be any number of cheeses, with or without holes).
Think of Chicago style as giving you the option of choosing lowercase for generic, nonliteral mentions. This in itself can be a mark of distinction—not of exclusivity, but of widespread acceptance. And in the case of champagne, it’s a way to keep your options open.