A process of manufacturing a polyester from cyclic ester monomer comprises the steps of: a) providing a cyclic ester, b) polymerizing the cyclic ester in the presence of a catalyst and optionally an initiator in a reactor to form a reaction mixture comprising polyester and unreacted cyclic ester, wherein after the polymerization at least one polymerization inhibitor is added to the reaction mixture, wherein the polymerization inhibitor is selected from the group consisting of monoimines, diimines, mono alkyl phosphates according to the formula RPO4H2, wherein R is a C6-16 linear, branched or cyclic alkyl group, di alkyl phosphates according to the formula R2PO4H, wherein each R is independently a C6-16 linear, branched or cyclic alkyl group or a combination thereof, and phosphate esters according to the general formula (I) wherein at least one of R′, R″ and R″′ has the general structure as in general formula (II) wherein n>0 and Q is independently a C1-16 linear, branched or substituted alkyl group, and R is independently an H or linear, branched, cyclic or substituted alkyl group or a phenyl group derivative, and wherein any of R′, R″ and R″′ not having the general structure as in general formula (II) is independently an H or a linear, branched, cyclic or substituted alkyl group or a phenyl group derivative.