Steamed mussels are a classic drinking food and are equally great with wine or beer. Choose one or the other based on what is used to steam the mussels and, of course, your own preference.
Minerally whites or pilsner with basic broths. When steaming mussels simply in white wine or beer with just a few aromatics, the flavor of the dish is really all about the mussels. For wine, opt for crisp, zingy whites with salty minerality, such as French Muscadet or Chablis (Chardonnay that can actually taste like oyster shells). A snappy pilsner is the beer equivalent and a great choice.
Rosé with tomato-based or porky broths. Along the Mediterranean coast, you’ll often find mussels cooked with tomatoes and pork-products, like bacon and chorizo. While these dishes won’t clash with a white wine, they often work better with wines that have a little bit more body and some berry fruit. Look for minerally rosés, like those from France as well as northern Italy. For beer, the slightly sweet-bitter-spiced flavors of Belgian pale ales, like Leffe Blond, work nicely.