An apparatus for quenching glowing coke in a coke-quenching container or car, comprises a housing with spaced front and rear vertical walls and vertical end walls at each end having respective entrance and exit openings for the quenching car. The housing also has a ceiling portion adjacent the upper end of a vertically elongated gas chamber defined within the housing and it communicates adjacent the rear wall with an upwardly extending flue. In order to ensure that any sensing devices in the flue are not influenced by the direct radiation from the glowing coke of the quenching car positioned in the chamber, the device includes a baffle extending outwardly from the rear wall and covers a cross-sectional area in the quenching chamber, but leaves a free gas flow cross-section for the flow of quenching gases which is as large as the area covered by the baffle.