A container has a longitudinal axis, and comprises an upper portion including an opening into the container, a sidewall portion extending from the upper portion to a lower portion, the lower portion including a base, and a pressure panel located in the lower portion substantially transversely to the longitudinal axis, the pressure panel being movable substantially along the longitudinal axis between an initial position and an inverted position to compensate for a change of pressure induced within the container. The pressure panel comprises an initiator portion and a control portion, the initiator portion adapted to move in response to the change of pressure prior to the control portion.