HVG Germany: Hopfen

 

Isomerisation of alpha acids in the brewhouse is naturally limited to a yield of less than 50% of the dosed alpha acids.

bild1.400w

Iso-alpha acids are also lost downstream in cold trub, through precipitation due to the fall in pH (e.g. 5.4 in wort; 4.4 in beer), through precipitation with yeast, sediment, trub and in filtration. The yield of bitter compounds should always be measured correctly on the basis of HPLC determined iso-alpha acids in the cast wort or in the finished beer, set in relation to the dosed alpha acid quantity, and not on the basis of spectrophotometrically determined beer units.

bild2.400w.ohne.kopf