A method of manufacturing an automatic dishwashing detergent product, provided as a discrete dosage unit and comprising a continuous, non-aqueous gel phase, includes manufacturing the gel phase by free radical polymerisation of monomer(s) in a non-aqueous reaction mixture to form a polymeric builder. The reaction mixture comprises at least one non-ionic surfactant which is an optionally end-capped alcohol alkoxylate; and one or more monomers comprising acrylic acid and optionally one or more further α,β-ethylenically unsaturated acids, wherein no more than 0.1 wt % of the total amount of the monomer(s) are crosslinking monomer(s).