Place each ear of corn with a tarragon sprig on a 14x12-in. piece of heavy-duty foil. Fold foil over corn and seal tightly. Grill corn, covered, over medium heat for 10-12 minutes or until tender, turning occasionally.
In a small bowl, combine the butter, soy sauce and minced tarragon. Open foil carefully to allow steam to escape; brush corn with butter mixture.