HVG Germany: Hopfen


Methods for wort and beer

1) Spectral photometric method – IBU, EBC BU
The wort (or the beer) is shaken out with soured iso-octan. From the non-polar phase the absorption is determined by spectral photometry at 275 nm which is a function of the content of bitter components.
The result is converted into bitter units by using a formula.

Absorption at 275 nm = 0,5
IBU = 0.5 x 50 = 25 IBU

2) HPLC methods
As described in the EBC 7.8 method, alpha- and iso-alpha-acids can be precisely determined in wort and beer by means of a gradient HPLC. There are other gradient methods which are based on the same principle.