Bratwurst Boil Time. Steaming all of them with simmering beer and onion slices within an aluminum pan is ok to help keep brats warm and juicy. Place the brats into this simmering beer/water and simmer on a lower heat for 20 minutes.

One that will fit your brats into it. Then, remove them from the cooking liquid and place on the direct heat side of the grill. The nhdsc recommends boiling bratwurst for 10 to 15 minutes or until the sausage is grey throughout.