Chocolate is bitter, astringent, and sour. Red wine is also bitter, astringent, and sour. Together, they reinforce the bitterness, astringency, and sourness of each other, and that's not a good thing. White wine tends to be even more acidic than red wine, so the chocolate will taste bitterer and the wine will taste sourer...A sweet chocolate paired with a less-sweet wine will make the wine taste sour just by comparison...don't be surprised if that pretty, balanced 13% Merlot you put on the table to drink with your chocolate mousse cake tastes vinegary after a bite of the sweet dessert.
Of course, if you want to eat and drink the two together, by all means continue to do so! (As I'm sure most of you will.) But a few mindful pairing tips should help alleviate any potential clashing:
The usual guidelines for food and wine pairing can apply here as well as anywhere else: like flavors with like, balance weights and textures, or go for a contrast if you're feeling avant-garde.
How do you feel about pairing wine and chocolate? Do you do it? Do you have a favorite wine and chocolate combination?
Read More: The Food Science of Wine and Chocolate at Palate Press