Abstract: The present application discloses a novel and advantageous method for the preparation of essentially odor-free alkali metal tetrahydroisohumulate (THIH) which proceeds through isomerization of the essential alkali metal tetrahydrohumulate (THH) intermediate, which is in turn produced by the hydrogenation with two moles of hydrogen of a starting alkali metal humulate (H) at a pH of at least 10, the intermediate THH being thus produced with relative ease and in high yields and purity, which high yields and purity carry over to the ultimate end product, namely, to the essentially aroma-, odor-, and impurity-free THIH, which end product accordingly does not require steam-stripping or other cleanup procedure as is conventional for THIH produced from other sources or by other procedure.

Abstract: New stable, concentrated aqueous solutions of tetrahydro iso-alpha acid (THIA) and hexahydro iso-alpha acid (HHIA) are disclosed. These solutions depend upon the presence of a second kind of iso-alpha acid to increase the solubility of both iso-alpha acids to a point outside of the ranges of their normal solubilities . . . in the case of THIA and HHIA, to a point above their solubility ranges and, in the case of unreduced iso-alpha acid (UIA) and dihydro iso-alpha acid (DHIA), to a point below their commercial prior-art solubility ranges. This "inversion" of solubility and stability behavior in water, which requires the presence of two different kinds of iso-alpha acids, is new to the art, and provides a novel approach for making commercially-desirable concentrates of THIA and HHIA available to the brewer.