Abstract: A method of making an aqueous composition containing iso-.alpha.-acids by isomerizing .alpha.-acids, preferably obtained by extracting hops with liquid carbon dioxide or organic solvents, in an aqueous alkaline medium is characterized by providing one or more salts in solution in the isomerized reaction mixture at a molar equivalent concentration greater than that of the iso-.alpha.-acids, whereby the reaction mixture separates into an oily phase and an aqueous phase, the oily phase containing a higher concentration of iso-.alpha.-acids than the aqueous phase, and recovering an aqueous composition containing iso-.alpha.-acids by separating the oily phase from the aqueous phase. The preferred salt is potassium carbonate which also provides a suitable pH for isomerization.