In August 1985, language maven* William Safire, in his then regular NYT column On language, tackled the topic of when, and when not, to use capitals in naming wines in English. It's a case of "the devil is in the detail" and, by the same token, an excellent example of the type of detailed knowledge into-English translators whose fields of specialising include wine, wine tasting, oenology and similar subjects need to master. See On language; wines without caps.
For more on the term 'language maven', see here.
Note that while I agree entirely with Steven Pinker's strong views on mavens, I also believe that detailed analysis of challenging topics in grammar, punctuation, typography, etc. by powerful minds such as Safire's can save practising translators a great deal of research and help them to compile their own style guides quickly and efficiently.
Quote:
Rule 3: When a wine is named after a grape, do not capitalize - unless the grape is named after a place and the wine comes from that place. ... Cabernet Sauvignon originated in Bordeaux, and if the wine comes from there, capitalize; cabernet is the name of the grape, not a city, and deserves no capital. ... Wine carrying the name tokay is named after a grape that is named after a town in Hungary, so the only time to capitalize a tokay is when the wine comes from around that town in Hungary.