packaging for a can containing ground roasted coffee packed under atmospheric pressure and having a flexible peel - off lid which is vented to allow the escape of a buildup of carbon dioxide gases . a spacing structure prevents the vent valve in the lid from being closed by contact with the plastic overcap . the spacing structure may include bosses on the overcap which engage the vent valve or a pocket in the overcap which allows the flexible lid to reach a maximum height without engaging the overcap . a permanently opened passageway may be provided between the plastic overcap and the rim of the can to further facilitate the escape of carbon dioxide .