Alpha acids vs flavor/aroma

Joewalla88 · Mar 11, 2019

Is there relation between alpha acids and flavor/aroma? Outside of IBUs I'm wondering how big of a role they play in other flavors. I think it's less related than I originally assumed. I did a brut IPA with Amarillo hops a couple months back, and a Denali hop brut IPA a couple weeks ago. They were similar recipes, both made with 8oz of each hop at the same additions. The Amarillo, however, was a lower ibu than the denali, but the Amarillo beer had more flavor and aroma. These were all whirlpool, and dry hopped beers, so maybe the timing has something to do with it too. Anyone else have an opinion on this? Or advice on what else to look at besides aa?

Gnomebrewer · Mar 11, 2019

No. Beta acids, essential oils and flavonoids in hops are responsible for flavour and aroma. Alpha acids isomerise in the boil to form iso-alpha acid, which is bitter. A hop can have low alpha acid, but be high in beta acid and essential oils, or vice-versa, or high in both, or low in both.

Joewalla88 · Mar 11, 2019

Gnomebrewer said:
No. Beta acids, essential oils and flavonoids in hops are responsible for flavour and aroma. Alpha acids isomerise in the boil to form iso-alpha acid, which is bitter. A hop can have low alpha acid, but be high in beta acid and essential oils, or vice-versa, or high in both, or low in both.

I figured that was the case. I need to do more research on the oil contents and stuff.

Northern_Brewer · Mar 12, 2019

Joewalla88 said:
I figured that was the case. I need to do more research on the oil contents and stuff.

Don't get too hung up on "oil contents and stuff" - they're not a particularly good predictor of flavour either. So much of flavour depends on compounds such as thiols which are present in minute quantities and are not generally mentioned on lab reports, and you can eg have an oil content that is high, but is made up of a compound which either doesn't taste of much or has a very high sensory threshold so contributes nothing to the flavour.

It's not a complete waste of time, but your time would be better spent just learning what hops actually taste of in your mouth and not on paper.

balrog · Mar 12, 2019

We need an IFU scale; international flavor units. Closest are those spider graphs you sometimes see, showing floral/spicey/citrus/woody/etc, but that's flavor and not intensity.

Joewalla88 · Mar 12, 2019

Yeah, I've noticed that sometimes those descriptors and graphs are helpful, but dont always tell the whole story. Im just trying to branch out a bit and try some new hops, and other hops I haven't used that much. Maybe there's a new favorite out there y'know. Amarillo and Mosaic are two of my favorites and to they pack a punch as far as flavor goes, but wouldn't mind a few more to put in the recipe rotation. These Denali hops are nice, I just wish I'd had two more oz or something just to make them pop a little more.