Mix the marinade ingredients in a medium bowl. Use one 12-ounce bottle of beer for every six to eight bratwursts. Combine the beer with a few spoonfuls of brown sugar, a little prepared Dijon mustard and some chili powder or hot pepper sauce to taste. For true Bavarian-style flavor use molasses and a little honey in place of the brown sugar and Worcestershire sauce instead of the chili powder or hot sauce. You can also use cider or cider vinegar instead of the beer or add a dash of citrus juice for a zesty alternative.

Poke several holes carefully with a fork in each bratwurst and place them in a large resealable plastic bag. Placing the bag in a shallow dish before filling it with the bratwurst and marinade often makes the task easier.

Set aside a one-half cup of the marinade for later use. Pour the rest over the bratwurst in the plastic bag and tightly seal the bag. Move the bag around in your hands to ensure the bratwursts get fully coated in the marinade. Place the brats in the refrigerator for at least 6 hours turning the bag occasionally. You can leave the bratwursts in the marinade for up to 24 hours before cooking them. When you remove the bratwursts from the bag, discard the bag and any marinade it contains.

Grill the marinated brats in foil packets with sliced onions. You can also put them on a grill rack directly over the coals and grill the onions in a little butter in a separate foil packet. Brush the brats with the reserved marinade once or twice during cooking.