Biotransformation is the process by which yeasts change less desirable hop compounds into more desirable bold flavours and aromas. ... Essentially, inert hop flavours are brought to life by yeast.

How are hops fermented?

Hops are then added throughout the boil at different segments, saving the aroma (finishing) hops for use toward the end. The later they are added in the process, the more their aromatics are emphasized and the less bitterness they impart. The beer is cooled, yeast is added, and then it ferments.

What process hops?

Today the vast majority of hops are processed into hop pellets or hop extracts. The key reaction in the brewing process is the conversion of alpha acid into iso-alpha acid to achieve the desired bitterness.