A method for treating a product containing additional ingredients in piece form or a mixed product consisting of a carrier fluid and such additional ingredients in piece form under aseptic conditions, • in which the product or mixed product is produced and/or provided at a first location and is filled cold at a second location; • in which the product or mixed product is conveyed in a forced manner from the first to the second location (I, II) and hereby experiences at least one heating, a heat retention, and a cooling; • in which a flow path (2/4) connecting the first and the second locations (I, II) in a fluid-conducting manner is provided, which flow path is designed as a main flow path with a bypass loop, wherein the following steps are provided: (a) in an initial phase, water or an adequate liquid medium is filled into and flows through the flow path (2/4); (b) the water or medium is conveyed for this purpose by means of a conveying apparatus arranged in the bypass loop; (c) at least the flow through the main flow path occurs at a product-specific conveying speed (c) which is regulated at a constant value; (d) a transition phase is initiated by switching from water or medium to the product or mixed product provided at the first location under the conditions of steps (b) and (c); (e) a position of a phase boundary (Lx), advancing at the conveying speed (c), between the product or mixed product and the water or medium is continuously determined; (f) when the phase boundary (Lx) has reached a predetermined distance (a) from a branching point at which, viewed in the flow direction, the main flow path branches into the bypass loop, a controlled transition occurs from the conveyance by the conveying apparatus to a forced conveyance which is effected by an application of pressure with a pneumatic pressure means on the product or mixed product provided at the first location and which now takes place exclusively and sustainably via the main flow path; (g) the product or mixed product pushes the water or medium out at the second location via the main flow path at the conveying speed (c) defined in step (c); (h) in a subsequent operation phase, the conveying speed (c) is generated by a first pressure to be provided at the first location in the product or mixed product, wherein such pressure is causally generated by a controllable propellent pressure (p) of the pneumatic pressure means which is dependent on the first pressure. • in which the product or mixed product is produced and/or provided at a first location and is filled cold at a second location; • in which the product or mixed product is conveyed in a forced manner from the first to the second location (I, II) and hereby experiences at least one heating, a heat retention, and a cooling; • in which a flow path (2/4) connecting the first and the second locations (I, II) in a fluid-conducting manner is provided, which flow path is designed as a main flow path with a bypass loop, (a) in an initial phase, water or an adequate liquid medium is filled into and flows through the flow path (2/4); (b) the water or medium is conveyed for this purpose by means of a conveying apparatus arranged in the bypass loop; (c) at least the flow through the main flow path occurs at a product-specific conveying speed (c) which is regulated at a constant value; (d) a transition phase is initiated by switching from water or medium to the product or mixed product provided at the first location under the conditions of steps (b) and (c); (e) a position of a phase boundary (Lx), advancing at the conveying speed (c), between the product or mixed product and the water or medium is continuously determined; (f) when the phase boundary (Lx) has reached a predetermined distance (a) from a branching point at which, viewed in the flow direction, the main flow path branches into the bypass loop, a controlled transition occurs from the conveyance by the conveying apparatus to a forced conveyance which is effected by an application of pressure with a pneumatic pressure means on the product or mixed product provided at the first location and which now takes place exclusively and sustainably via the main flow path; (g) the product or mixed product pushes the water or medium out at the second location via the main flow path at the conveying speed (c) defined in step (c); (h) in a subsequent operation phase, the conveying speed (c) is generated by a first pressure to be provided at the first location in the product or mixed product, wherein such pressure is causally generated by a controllable propellent pressure (p) of the pneumatic pressure means which is dependent on the first pressure.