A steam peeling system has a pressure vessel (1) which is charged with steam for a peeling cycle period at the end of which steam discharge is effected to an exhaust tank (6) via an exhaust valve (14). The steam charging action is regulated to achieve, at a predetermined stage of the peeling cycle period, a target value for a parameter indicative of a desired peeling result. This parameter may be a temperature value for an outer surface region of product to be peeled or a measure of the temperature of the steam within the pressure vessel (1). The required regulation of the steam charging action may be achieved by the supply of steam, for a first part of the peeling cycle period, to the pressure vessel (1) being effected via a main steam line (12) and on/off steam supply valve (13). At a time before the end of the peeling cycle period, the main steam supply is shut off and inflow of steam to the pressure vessel (1) is continued for at least a part of the remainder of the peeling cycle period, at a rate which is reduced compared with that available via the main steam supply route, by way of a bypass line (22). The bypass steam flow is controlled by a valve (23) in line (22) in response to control signals established by controller (27) based on a measurement by transducer (24) of the pressure within vessel (1) as present also in exhaust line (10) which is in open communication with the interior of the pressure vessel.Further arrangements to achieve pressure regulation are also described, as is a rotational programme applicable to an peeling installation using a rotary pressure vessel.
