A method for forming a multi-compartment bag comprising the steps of: a. draping a portion of a continuous sheet of bag forming material around a primary fill pipe so that two plies of the sheet meet inward of a first and a second longitudinal edge along a first seal line, leaving flaps extending beyond the first seal line to the first and second longitudinal edges of the sheet; b. draping the flaps around at least one secondary fill pipe so that the first and second longitudinal edges of the sheet meet at a second seal line; c. forming longitudinal seals along the first and second seal lines; characterised in that the method further comprising the steps of: d. forming a transverse seal comprising transverse seal areas below the primary and secondary fill pipes to form a bag having a first compartment encircling the first fill pipe and at least one secondary compartment encircling the secondary fill pipe or fill pipes, so that a transverse seal area of the at least one secondary compartment at least partially overlaps with a transverse seal area of the first compartment whereby, as a result of the overlapping transverse seal, the secondary compartment is folded against the first compartment and is fixed in this position; e. metering a primary material into the first compartment and one or more secondary materials into the secondary compartment or compartments. a. draping a portion of a continuous sheet of bag forming material around a primary fill pipe so that two plies of the sheet meet inward of a first and a second longitudinal edge along a first seal line, leaving flaps extending beyond the first seal line to the first and second longitudinal edges of the sheet; b. draping the flaps around at least one secondary fill pipe so that the first and second longitudinal edges of the sheet meet at a second seal line; c. forming longitudinal seals along the first and second seal lines; characterised in that the method further comprising the steps of: d. forming a transverse seal comprising transverse seal areas below the primary and secondary fill pipes to form a bag having a first compartment encircling the first fill pipe and at least one secondary compartment encircling the secondary fill pipe or fill pipes, so that a transverse seal area of the at least one secondary compartment at least partially overlaps with a transverse seal area of the first compartment whereby, as a result of the overlapping transverse seal, the secondary compartment is folded against the first compartment and is fixed in this position; e. metering a primary material into the first compartment and one or more secondary materials into the secondary compartment or compartments. d. forming a transverse seal comprising transverse seal areas below the primary and secondary fill pipes to form a bag having a first compartment encircling the first fill pipe and at least one secondary compartment encircling the secondary fill pipe or fill pipes, so that a transverse seal area of the at least one secondary compartment at least partially overlaps with a transverse seal area of the first compartment whereby, as a result of the overlapping transverse seal, the secondary compartment is folded against the first compartment and is fixed in this position; e. metering a primary material into the first compartment and one or more secondary materials into the secondary compartment or compartments.