Trim fat from roast. Rub soy sauce over surface of roast with fingers. On a large piece of foil combine aniseed, fennel seed, caraway seed, dill seed, and celery seed. Roll roast in seeds to coat evenly. Cover roast in foil and let stand in the refrigerator for 1 to 2 hours or overnight.
Remove foil from roast. If necessary, cut roast to fit into the crockery cooker. Place roast in a 3 1/2, 4, 5, or 6-quart crockery cooker. In a small bowl dissolve bouillon granules in water; pour around roast. Cover; cook on low-heat setting for 10 to 12 hours or on high-heat setting for 5 to 6 hours.
Transfer roast to a serving platter. Garnish platter with apple wedges and mint sprigs, if desired. Strain cooking juices; pass juices with roast.