In a dutch oven or large saucepan, combine onion, beer and water. Add brats and bring mixture just to a boil. Turn heat off. Remove pan from heat. At this point you can let the brats sit in the beer/water mixture, for up to one hour. Drain beer/water mixture, proceed with grilling directions.
Step 2: Grill Brats
Prepare gas or charcoal grill, discard beer/water mixture, grill par-boiled brats on gas or charcoal grill, grill until brats are golden brown on all sides.
*Do Not Pierce Brats when grilling*
Step 3: Prepare Beer Kraut Sauce
In a 10-inch skillet, heat oil over moderate heat. Add onion and garlic, cook for 5 minutes. Add beer, juice or broth, brown sugar, vinegar, bay leaves, and caraway seeds. Stir in Worcestershire sauce and pepper. Bring to a boil, lower heat, add sauerkraut and grilled brats. Simmer on low to med-low for 45 minutes to an hour. Discard bay leaves before serving.