A method for producing a proanthocyanidin extract is described. The method comprises: (a) providing a volume of proanthocyanin-containing liquid feedstock; (b) passing the proanthocyanin-containing liquid feedstock to an ultrafiltration feed tank; (c) filtering the material in the ultrafiltration feed tank through an ultrafiltration membrane system to fractionate the material into a proanthocyanin-reduced permeate stream and a proanthocyanin-enriched retentate stream; (d) collecting the proanthocyanin-reduced permeate stream; and (e) passing the proanthocyanin-enriched retentate stream to the ultrafiltration feed tank until the volume of proanthocyanin-containing liquid feedstock is exhausted and thereafter collecting the proanthocyanin-enriched retentate stream.