The most important bitter substances in wort and beer are the iso-α-acids. In addition, β-acids and δ-acids can be identified as well, primarily in the wort. Furthermore, wort and beer contain other derivatives from the acids of the bitter substances found in hops, particularly products of oxidation, which can also contribute to the bitterness in beer.
Determination of iso-α-acids, α-acids and β-acids in beer, beer-based beverages and wort
Suitable for all beer, beer-based beverages and wort
iso-α-Acids (isohumulones), α-acids (humulones) and β-acids (lupulones) are chromatographically separated using this method.
The bitter substances are chromatographically separated by means of RHPLC. The humulones and lupulones are detected at 314 nm, whereas the iso-α-acids are detected at 270 nm.
Equipment
Analytical balance, ± 0.0001 g
Water bath, 20 °C
Ultrasound bath
Centrifuge, 750 g
Vials, crimp caps, crimping tool
Disposable syringes, 20 ml
Syringe filter, 0.45 µm, PTFE
High performance liquid chromatography set up for gradient operations, column oven 35 °C, UV-VIS detector (270 nm and 314 nm)
High pressure liquid chromatograph and UV-VIS detector, equipped for gradient operation
HPLC column, Machery & Nagel CC 125 / 4 Nucleodur 100 5 C18 EC or a comparable column
Graduated cylinder, 1000 ml, 50 ml
Beaker, 50 ml
Volumetric flasks, 100 ml, 50 ml
Volumetric pipettes, 30 ml, 10 ml
Erlenmeyer flask, 100 ml