How to Make It
Place ribs in a large shallow dish or zip-top freezer bag.
Combine juice concentrate and next 6 ingredients in a small bowl with a wire whisk. Reserve 3/4 cup mixture in refrigerator for dipping. Pour remaining mixture evenly over ribs; cover or seal, and chill 8 hours, turning occasionally.
Remove ribs from marinade, discarding marinade. Place 1 rack of ribs in bottom of a 6-quart slow cooker; stand remaining rib racks on their sides around edges of slow cooker. Cover and cook on HIGH 1 hour. Reduce heat to LOW, and cook 5 hours.
Microwave reserved 3/4 cup sauce in a 1-cup glass measure at HIGH 1 to 1 1/2 minutes or until thoroughly heated, stirring once. Serve with ribs. Garnish, if desired.
Stand Your Ribs: Standing these ribs along the sides of your slow cooker gives them direct contact with heat, so they'll have crispy brown edges like ribs that have smoked for hours.
Southern Living Slow-Cooker Cookbook