A novel method to extract and purify cereal .beta.-glucan is described. Cereal .beta. glucans are distinctive polymers of glucose differentiated from other polymers not only by their source but also by their physicochemical properties. The high purity of the cereal .beta.-glucan obtained according to the present invention allows for the preparation of clear, colourless viscous liquid preparations. These liquid preparations are stable to gelling effects when kept at ambient temperatures and low ash concentrations. Compositions comprising .beta. (1-3) .beta. (1-4) glucan and a freezing point depressant are also, described.