Abstract: An improved process for the selective extraction of the alpha acids contents of hops using liquid carbon dioxide as solvent is described. Solubility of the alpha acids in liquid carbon dioxide is enhanced by addition of a minor amount of a selected organic substance which: (1) is non-reactive with the alpha acids of interest, and (2) has the following physical properties: (a) is completely soluble in liquid carbon dioxide in the operating conditions and concentrations employed, and (b) is itself a solvent for the alpha acids of interest. Preferably the organic substance is a 1 to 4 carbon atom aliphatic alcohol in an amount of about 0.1 to about 30 volume percent.

Abstract: There is provided a method of processing hops or hop extracts for brewing in which hops and particularly the alpha acids in the hops are stabilized against deterioration and light sensitivity, the process broadly comprising isomerizing a substantial portion of the alpha acids in the hops and contacting said iso-alpha acids witha metallic hydride compound, the metal thereof being suitable for use in foods, until the reaction is substantially completed. In another aspect, the alpha acids present in the hops are converted to their reduced isomerized products which are desirable for brewing. The process is especially suitable for use in pelletizing operations.

Abstract: There is provided a method of processing hops for brewing in which the hops and particularly the alpha acids in the hops are stabilized against deterioration, the process broadly comprising forming an intimate mixture of the hops or hop extracts with one or more oxides of a divalent metal or metals and maintaining the mixture under suitable conditions, preferably at an elevated temperature, e.g., 40.degree.-100.degree. C., until stabilization is substantially completed. In another aspect, the alpha acids present in the hops are converted to their isomerized products, which are desirable for brewing. The process is especially suitable for use in pelletizing operations.