Described is a method for preparing a purified liquid containing carbohydrates. The method comprises the steps of: hydrolysing starch to a dextrose equivalent (DE) of 10 or above, thus obtaining a liquid of carbohydrates; removing a heavy weight sludge fraction from the light weight liquid of carbohydrates using centrifugation; filtering the remaining liquid of carbohydrates, the filter being capable of retaining coarser particles while allowing particles with a diameter less than 2 μm to pass; performing membrane separation on the filtered liquid of carbohydrates using a membrane having a pore size at 2 μm or below; and recovering a permeate stream of purified liquid containing carbohydrates. Also disclosed in a plant for performing the method.