Solid-Phase Extraction of Hop Acids from Beer or Wort for Subsequent Analysis. James R. Donley, Anheuser-Busch, Inc., Technical Center, One Busch Place, St. Louis, MO 63118. J. Am. Soc. Brew. Chem. 50:0089, 1992.

A procedure for extracting hop acids from beer or wort was developed. A solid-phase extraction procedure employing a 3.0-ml Bakerbond spe* octyl column was used to absorb the hop compounds. After the concentrated hop compounds were washed, they were desorbed with methanol. UV measurement of either international bitterness units or high-performance liquid chromatography (HPLC) was used to determine the amount of hop acids present. UV analysis could be correlated with the ASBC-recommended procedure for bitterness units. HPLC analysis allowed quantitation of hulupones, humulinic acid, isohumulones, humulones, lupulones, ?-isohumulones, and tetrahydro-isohumulones. Recovery of isohumulones is better than 90%, and recovery of other specific hop compounds is better than 75%.

Keywords: Hop resins, HPLC, International bitterness units, Solid-phase extraction