Abstract: Hop extract in, e.g., hexane, pre-isomerized, optionally pre-reduced, is extracted with aqueous KOH to give potassium isohumulate of 80%+ and preferably 90%+ purity. The hexane phase containing the remainder of the isohumulones is stripped of solvent and is suitable for kettle addition. In order to prevent foaming during subsequent concentration, the aqueous extract containing about 6% solids is acidified to a pH less than the pK.sub.a of isohumulone and is concentrated under reduced pressure. After concentration, the material is treated with KOH to form the water soluble isohumulone salt which is added to beer post-kettle. At a critical optimum pH range, dependent upon the ratio of water to hexane phase used in the initial extraction, from 0.1 to 0.75 of the isohumulones may be extracted in the highly purified form. A generalized technique for establishing conditions that will give such desired fractions and residues is disclosed.