Isomerising hops extract to form iso-alpha-acids for beer - treating with strong acid before alkali isomerisation

摘要

Process comprises extracting the hops alpha-acids with an organic solvent and transferring the alpha-acids from a non-polar water-immiscible solvent to water to form a soln. of alkali metal alpha-acid salts. Before conversion to the salt form, the alpha-acids are contacted with sufficient aq. strong acid to give a pH in the aq. phase after contact of 1. A particular process comprises contacting a soln. of the extract in a non-polar solvent of b.pt. 100 degrees C with aq. acid as above, then contacting it with a substantially anhydrous base from hydroxides and carbonates of Na and K, then heating at 100-150 degrees C to form iso alpha-acids salts, then extracting with water at pH 8-9.5 and sepg. The product is used in beer making. The acid treatment results in higher and more constant yields.