A valve, including: a valve seat including a seating surface with an outer edge furthest, an inner edge, and a first portion; and a valve body including a sealing surface with an outer edge, an inner edge, and a first portion. In a closed position, the first portion of the sealing surface is in contact with the first portion of the seating surface to block flow through the valve. The sealing surface tapers from the first portion of the sealing surface to the inner edge of the sealing surface or the outer edge of the sealing surface, or the seating surface tapers from the first portion of the seating surface to the inner edge of the seating surface or the outer edge of the seating surface. In the open position, the first portion of the sealing surface is free of contact with the first portion of the seating surface.