Alpha acids and aroma hops

[Brewberoza]

thank guys kinda what I have been doing, :drink: I think!

 

[zgoda]

I was surprised when calculating hops for my 1st brew with New World hops. 50 gms Galaxy @14% aa for aroma & flavour left me with 10 gms Hallertau @4.5% aa for bittering (I was targeting ~25 IBU @21 ltr brew length). I guess if I would want to use Mosaic @17% aa the brew would not have any bittering hops at all.

 

[anthonyUK]

Some hop suppliers state additional data for compounds such as cohumulone which is a main factor in bitterness type (harsh vs smooth) and myrcene/humulene for aroma.

 

[Vossy1]

interesting question basically is aroma directly proportional to AA.

I'd have to say no.
As per Anthony's reply it's mainly hydrocarbon components in the essential oils in hops that provide aroma, Fix states they "are responsible for the overall hop presence, particularly the hop aroma". Also keep in mind that boiling drives off essential oils so a high AA hop introduced at the start of the boil may contribute little in the way of overall hop presence due to a lot of the essential oils being driven of, but add it as a steeping hop and it's a different story.
This is quite a complex subject, well worth a read of a good book like Principals of brewing science or Brewing by Lewis and Young for a 'fuller' picture.

 

[Brewberoza]

Asked a friend of mine the same questions. He is studying for his brewing diploma and said no. Alpha acids have little to do with flavour or aroma. It is other compounds like Myrcene oil and Humulene Oil that are aromatic. Like alpha acids they vary from crop to crop and may deteriorate over time if hops are not properly stored. Unlike alpha acids, I have never seen the quantities displayed on any packet of home brew hops. Perhaps commercial brewers may receive hop analysis sheets but home brewers are in the dark.

Best guess is consistent weight I suppose?

A good resource for any one wanting to learn more is beerlegends /hops-varieties