[KellerBrauer]

Greetings — I brewed my first NEIPA yesterday.  The recipe I’m using calls for huge hop additions during fermentation, although I don’t I don’t understand why.  So, I’m reading the new style 21c (Hazy IPA) from the 2021 BJCP and on this subject in the Characteristic Ingredients paragraph, it states: “Biotransformation of hop oils during fermentation adds to the depth and fruit complexity”.  Anyone have any idea what that means?  Biotransformation??

[pete b]

Yep. I am not the one to explain it and I am sure that there is plenty info on the web. Basically particular yeast strains have beneficial chemical reactions with hops creating different flavors and aromas.

[rburrelli]

Yep. Tons of information out there. Scott Janish has a lot on his website.  Plus good info on some hop combinations that work.  It does not happen with all hops and yeast.

[reverseapachemaster]

Basically some yeast can transform hop compounds into other compounds which produce different flavors and aromas. Current research is inconclusive about all the compounds that can be transformed and which of all brewing yeast transform which compounds. Biotransformation occurs with active fermentation which means everything coming in from the hot side plus anything added during active fermentation can be transformed if the right combination of yeast and hops are together.

Depending on your yeast choice it's very likely you've experienced biotransformation of hop compounds from the boil/flameout/whirlpool and didn't know it was happening. What changed with the hazy style is dry hopping during fermentation became a technique for those beers (mostly to rush them out the doors) and they accidentally discovered that adding more hop compounds at the beginning or middle of fermentation gave access to new flavors.

I'm not much of an IPA brewer so that's about the extent I know on the subject. Scott Janish's website is a better resource.

[KellerBrauer]

Thanks for the info, brewers!  I’ll look into Scott Janish’s website for information.

Thanks again!