Abstract: An oven for cooking foodstuffs includes an airtight enclosure having an opening closed by a door. Water condensing in the enclosure is collected in the lower part of the enclosure and discharged into discharge pipes. An excess steam circuit captures excess steam escaping from the enclosure and feeds the captured steam to a treatment system including a steam condenser to convert it into liquid condensates. The liquid condensates are collected and discharged into discharge pipes. At least one heater heats steam passing through it in the excess steam circuit on the upstream side or on the downstream side of the steam condenser.