Be a wine snob!
Wine snobbery, along with an upper-class accent and a superciliously raised eyebrow, is one of the great, easy markers of the upper class. If the PCs hobnob with nobles, then they must drink wine. Invent a superior wine for the extra-elite to drink: it won’t take long before the PCs will know when they’re getting the best.
When giving PCs wine, let them make a History check. If they succeed, they know the wine’s quality, and the player may talk about its “oakiness”, “untertones of astral currant” and “tanens” for one full minute before anyone is allowed to hit them.
Wine snobbery, and overpriced vintages, have been around forever. A good Tokay was quite expensive in the medieval period, and Louis XV called it the “Wine of Kings, King of Wines”. Falernian is mentioned in a lot of Roman authors. On a wall in a Pompeii bar it says: “For one coin you can drink wine. For two you can drink the best. For four you can drink Falernian.”
In my campaign, I’ve invented a few beverages. The Talasay is the most sought-after: a bottle of the Talasay ’82 in a treasure horde might be worth more than the rest of the treasure. Its quality is only exceeded by the emerald wine of the fey lords, after drinking which, it is said, all other wines taste like ash. On the other side of the spectrum, there’s Dogsbreath, good enough only for dwarves to drink.