In this process for preparing a .beta.-1,3-glucan, the glucan-containing matrix is treated with a protein having .beta.(1,3)-glucanase activity, wherein the concentration of the glucanase amounts from 0.001 to 3.0% by weight. The glucan-containing matrix can be a fermentation broth, a culture medium or a suspension, where appropriate containing unsolved solids, cell constituents and/or cell fragments, or else a mycelium, a hydrocolloid or a powder preparation having a solvent proportion of from 20 to 99.9% by weight. The duration of the enzymatic treatment should be between 15 minutes and 24 hours and the treatment should be carried out continuously. The invention also envisages the glucan-containing matrix being filtered or centrifuged, after it has been treated enzymatically, and the glucan finally being separated off. A .beta.-1,3-glucan which has been prepared in this way and which exhibits, for example, improved solubility in cold water, reduced proportions of insoluble constituents, an increased viscosity or improved filterability, is also claimed. A solid formulation and the use of these glucans for cosmetic applications, foodstuffs or oil production are also coclaimed.