Beef Brisket w/Sauce in Slow Cooker

This beef brisket is great alone or as a sandwich.  I made the sauce that the recipe describes, but we did not even use it!  The beef was that tasty.  Great for a weekend meal since you make it in a slow cooker.
****The measurements for the ingredients are for a 3 1/2- or 4-quart slow cooker.  For a 5- or 6-quart slow cooker (like mine) double the cooking liquid ingredients, reserving still only 1/2 cup for sauce.  Leave all other ingredient amounts the same.  Makes 6 to 8 servings.****

Ingredients:

3/4 cup water
1/4 cup Worcestershire sauce
1 tablespoon vinegar (I used apple vinegar b/c I had it left over from a dessert recipe)
1/2 cup beef broth (this is my modification; the recipe called for 1 teaspoon instant beef bouillon granules but I didn't have any in the house)
1/2 teaspoon dry mustard
1/2 teaspoon chili powder
1/4 teaspoon ground red pepper (I used red pepper flakes, worked fine for flavor but you can see the flakes)
2 cloves garlic, minced
A 2 1/2-pound fresh beef brisket (try to pick the one with the least fat to save time trimming)
1/2 cup catsup
2 tablespoons brown sugar
2 tablespoons butter or margarine

Instructions:

For cooking liquid, in a bowl combine water, Worcestershire sauce, vinegar, bouillon granules or beef broth, dry mustard, chili powder, red pepper, and garlic. Reserve 1/2 cup liquid for sauce; set aside in refrigerator.

Trim fat from meat.  If necessary, cut brisket to fit into a 3 1/2- or 4-quart crockery cooker.  Place meat in crock pot.  Pour remaining liquid over brisket.

Cover and cook on low-heat setting for 10 to 12 hours or on high-heat setting for 5 to 6 hours.

For sauce, in a small saucepan combine the 1/2 cup reserved liquid, catsup, brown sugar, and butter.  Heat and pass sauce with meat.