HVG Germany: Hopfen

Parameters which influence the isomerisation:

  • • boiling time
    • temperature/pressure
    • pH
    • original gravity concentration
    • wort turbidity
    • level of bitter substances
    • kind of wort copper / mixing intensity
    • hop product

Yield of bitter substances

In the brewery the yield results from the ratio between the remaining bitter substances in the finished beer and the bitter substances dosed with the hops according to the following rule:

Yield = (bittersubstances in beer / bitterhop in doses) x 100

and is calculated as the isomerising rate as follows:

Isomerisierungsrate = ( Iso - ? - Säuren in Würze oder Bier / ? - Säuren dosiert ) x 100

The HPLC analysis is the best way to determine the alpha and iso-alpha acids actually dissolved.
The method for analysing the bitter substances in wort and beer can be seen in the chapter "The Plant" - under the subtitle: Hop analytics.
In the brewery there are various ways and means of influencing the yield of bitter substances and quality of the bitter substances: ways and means massnahmen.pdf