Isomerisation
Term from the Brauwerkstatt brewing glossary, category “Brewing and equipment”.
Explanation
During the boil the alpha acids in hops turn into soluble, bitter compounds. That is why hops boiled for a long time give a lot of bitterness, while late hops mainly give aroma.
Test your knowledge
What happens during isomerisation?
- Alpha acids from the hops become bitter and soluble during the boil
- Protein flocculates
- Sugar turns into alcohol
Show answer
Correct: Alpha acids from the hops become bitter and soluble during the boil. Only boiling turns alpha acids into iso-alpha acids. That is why hops boiled for a long time add a lot of bitterness.