Cooking brats in beer is a popular way of cooking brats on the stove OR parboiling before grilling. There's just something magical about brats and beer together, they're just made together like peanut butter and jelly!  Many people will cook or steam the brats in liquid to add extra flavor before you cook the bratwurst on stove top or before grilling. Simmering the brats in beer AFTER cooking is also a great way to keep brats warm and juicy before serving them to a crowd.