Combine spareribs and water to cover in a large Dutch oven. Add salt, pepper, Worcestershire sauce, and bouquet sauce; stir well. Combine onion, celery leaves, and garlic; tie securely in cheesecloth. Place cheesecloth bag in sparerib mixture. Bring to a boil ; cover and simmer 2 hours or until ribs are tender.
Remove spareribs to a warm serving platter and cover. Discard cheesecloth bag, and reserve 2 cups cooking liquid in Dutch oven.
Combine flour and 1/3 cup water; stir until smooth. Pour flour mixture into reserved cooking liquid ; cook, stirring constantly, until thickened and bubbly. Pour gravy over warm spareribs, and serve immediately with hot cooked grits, if desired .