In some embodiments, a lid may include a valve chamber comprising a hollow chamber, a valve flap and a hinge. The hollow chamber may be defined by one or more sidewalls and have a first opening at a first longitudinal end and a second opening at an opposing, second longitudinal end. The valve flap may be positioned at least proximate to the second longitudinal end and have a shape and size substantially the same as a shape and size of the second opening. The hinge may couple the valve flap to a sidewall of the one or more sidewalls and may be sized and configured to enable the rotation of the valve flap from an open position to a substantially closed position. Container assemblies and methods of forming lids are also disclosed.