Abstract: A valve (10) is disclosed which is operable to automatically transition from a closed state to an open state in response to heat. The valve (10) includes: a cover (12) having at least one opening (12a) therein; at least one adhesive layer (32, 36) for sealing a perimeter of the cover (12) to a wall (22) of a food cooking package (20) on which the valve (10) is positioned; and, a deformable element (14) that shrinks in response to being exposed to heat, the deformable element (14) having a perimeter which is sealed by an adhesive when the valve (10) is in its closed state, wherein shrinking of the deformable element (14) pulls the perimeter of the deformable element (14) away from a site where it is sealed by the adhesive, thereby breaking the seal about the perimeter of the deformable element (14) and transitioning the valve (10) from its closed state to its open state.