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 bittering units in beer, beer-based beverages and wort
This method is not suitable for beer, beer-based beverages or wort, which contain saccharin, p-hydroxybenzoic acid ester, salicylic acid or sorbic acid.
The bitter substances, primarily iso α-acids, are extracted using iso-octane from the acidified sample, and their concentration in the extract is determined spectrophotometrically [1].