Abstract: A module adapted to generate a stream of hot and humid air, operating in conjunction either with a proofing chamber in which dough pieces are raised prior to baking or in conjunction with a holding chamber in which cooked food is maintained in a hot, moist state. The module is provided with a replenishable water reservoir from which water is fed into a steam generator in which the water is boiled to generate steam. Included in the module is a duct through which air is forced by a blower and an air heater disposed in the duct is used to heat the air. A conduit connects the steam generator to the duct and allows exhaust of steam into a positive-pressure zone (high pressure, after the blower) to effect a proofing action when the module is operated in proofing mode. Steam can also be fed into a low-pressure zone in the duct (at the blower inlet) to produce a stream of hot and humid air at a higher temperature whereby the module is operated in a food holding mode.