| 摘要 |
<p>A method of purifying aqueous solutions of iso-.alpha.-acids by removing .beta.-acids therefrom comprises first bringing the solution to an iso-.alpha.-acid concentration of 0.5% to 10% w/w, particularly 0.5% to 5% w/w, then reducing the pH to a value in the range 7 to 10, preferably 8 to 9, so as to form an easily filtered precipitate of .beta.-acids. Preferably pH reduction is effected by bubbling carbon dioxide through the solution. The separated iso-.alpha.-acid solution may be concentrated to an extent that a phase separation takes place into two aqueous phases one of which has a higher iso-.alpha.-acid concentration than the other. The recovered iso-.alpha.-acid solution is suitable for direct addition to beer without haze formation.</p> |
