Boil volume - does it affect hop flavour and aroma

[bry2]

It seems to be well documented that the utilisation of hops for creating bitterness is affected by the boil volume (bigger is better). But what about flavour and aroma? If I am only doing less than 20 minute hop additions and am not concerned about getting much bitterness out of the hops, does it really mater if I boil 1-2 litres without increasing the mass of hops (to account for utilisation)?

The reason why I ask is my guess would be that boiling the hops in 1040 gravity wort with late editions will give slightly different flavour and aroma profiles to steeping in hot water or dry hopping (and I'm not talking about bitterness being the difference).

 

[carpedaym]

This is a really good question and I won't be able to give you the answer you're looking for, however I've been looking into a related issue and thought I'd share what I found out.

A lot of people say that boiling hops in only water gives a grassy taste. The scientific explanation is supposedly because the grassy "polyphenols or tannins react with proteins during wort boiling and aid in trub formation" (see this BYO Mr Wizard question, it might be worth a read although again they're talking about bitterness).

I couldn't find a lot of first hand accounts of the the claim that water-only-boil gives grassiness, so it was hard to tell if just it was one of those homebrew rumors that seem to propagate themselves, especially since a lot of people seem happy to french press a hop tea.

If that science is legit, I suppose the question would be whether the desirable hop oils react with the wort proteins at all and drop out into trub. My completely uneducated guess is no; that a higher gravity would only limit the alpha acid isomerization and not inhibit extraction of the flavoursome and tasty oils.

 

[roverfj1200]

When doing hop boils for K and K I have used 1L to 7L boils using ME or Dex to get the Gravity to 1040. I have found That using Dex is easy and in a 5 litre boil gives good results. Steeping hops in hot water is a waste of time in my opinion..

So I would use Dex if you are using it or ME in the boil and do a 5L boil.

Cheers.