Alpha acids and aroma hops

[Brewberoza]

Beer (apparent) bitterness can be measured by taking into account alpha acids and alpha acids units.

The question is what does alpha acids contribute to flavour and aroma hops? Does it have any effect? Is there need to re-scale recipes when hops alpha acids are different from brew to brew or will keeping consistent weight of consistent variety yield consistent results?

 

[Vossy1]

Is there need to re-scale recipes when hops alpha acids are different from brew to brew or will keeping consistent weight of consistent variety yield consistent results?

Yes, each crop will have a differing AA level which will contribute more or less to the beer. Have a play with the forum bitterness calculator (top left) to see how it affects the outcome. Higher gravities can also affect AA's so it's not just about the hop AA :thumb:

 

[paulpj26]

Yeast strain can also affect the bitterness of the finished product as different yeast strains will absorb different amounts of AA and other compounds.

Also be careful when scaling recipes up with hops that have low AA as using too many hops cones in a given wort can impart a vegetable flavour (although the same variety of hop shouldn't vary enough from year to year for this to be a problem)

:thumb:

 

[Vossy1]

Also be careful when scaling recipes up with hops that have low AA as using too many hops cones in a given wort can impart a vegetable flavour

I've never found that to be a problem, but then again I haven't used all hops in big quantities, I have however used 500g+ in 25ltr batches and never had this happen, I'd usually attribute vegetal flavours to faults. Any tips as to which hops to avoid much appreciated

 

[paulpj26]

We're really talking about the hops at the lower end of aa scale so what you would consider the "noble" hops. Having said all that you would really have to over do it in order for it to be a problem.

500g in a 25ltr brew is hell of a lot though!! What hops were they?

 

[Vossy1]

500g in a 25ltr brew is hell of a lot though!! What hops were they?

They were low AA (2.6%) Hallertau Mittelfruh, hence my query re the vegetable issue. I've made a lot of Durden Park strong IPA's/ales using massive amounts (figuratively compared to beers now) of EKG, Fuggles and when feeling cheeky noble hops, mostly Mittelfruh but some others too :P , and have not experienced this problem, hence wanting to know which hops might do so :hmm:

 

[paulpj26]

Then I stand corrected lol it was something I heard off brew strong, I've personally never experienced it but then again I never go overboard with my hops.

I bet there wasn't much wort left after all those hops!!!!

 

[calumscott]

I've only done the one "stupid amounts of hops" and that was a stupid amount of high AA hops and well, even if there were veggie flavours in there you wouldn't notice them past the mountain of late additions! :lol:

 

[Vossy1]

I bet there wasn't much wort left after all those hops!!!!

Nope, the hops had to be hand rinsed/sparged several times, have kind of got used to it now, but it was very odd at the time...sanitisation and all that
It's really worth trying a big hop big beer brew/traditional IPA, even if just once...they mature in a way smaller beers don't with tastes you'll never experience unless you try it ...and on the plus side you can usually parti gyle and make 2 beers for one :drink:

 

[PD]

quote

've only done the one "stupid amounts of hops" and that was a stupid amount of high AA hops and well, even if there were veggie flavours in there you wouldn't notice them past the mountain of late additions! :lol:


and having sampled this beer from Calum all I can say is.............


I would have loved some kind of vegetable flavor in the brew............... :lol: :lol:

serious hopping is not something I will aspire to. :)

 

[Vossy1]

serious hopping is not something I will aspire to.

Well that depends, if you want to make some of the best beer you'll ever taste, you'll aspire to it. The Durden Park Circle recipe book is highly regarded as one of the definitive books on old ales, though you have to be prepared to wait for the results, but when they come they are like nothing you will have tried before...not for every one though, I understand that. To dismiss highly hopped brews so easily is madness...if you think all they contribute is bitterness...you're losing out

 

[graysalchemy]

The beer i think PD is referring to is Calums uber hoppy APA which to me even though it had scarily high IBU's went down a treat, it didn't particularly taste overly bitter or harsh.

The only problem was he only sent me one bottle :evil: :evil: and it was a little one at that. :lol: :lol:

I must try one of these Durden Park pale ales one day. :hmm: :hmm:

 

[dennisking]

I must try one of these Durden Park pale ales one day. :hmm: :hmm:

Lost count of the amount of times I've opened the book and thought, right time to brew one, only for the recipes to frighten the life out of me. :shock:

 

[calumscott]

The beer i think PD is referring to is Calums uber hoppy APA which to me even though it had scarily high IBU's went down a treat, it didn't particularly taste overly bitter or harsh.

The only problem was he only sent me one bottle :evil: :evil: and it was a little one at that. :lol: :lol:

Fear not. I like it so much that I'll be doing it again some day reasonably soon. I could do you a 2l placky bottle if that suits...? :lol:

 

[graysalchemy]

This one on their site didn't seem to bad, nice and simple

William Black's X Ale (1849)
O.G. 75

For 1 gallon (4.5lt):
3.25 lb (1475g) Pale Malt
1.1 oz (32g) Goldings Hops


Mash grain for 3 hours at 150º F (66±1º C). Raise temperature to 170º F (77º C) for 30 minutes.

Sparge with hot water at 180 - 185º F (82 - 85º C) to O.G. or required volume.

Boil with hops for 90 minutes.

Cool and ferment with a good quality ale yeast.



Mature for at least 6 months.

Until I put it into Brewmate and saw 76 IBU's and over 18kg of grain when converted to 55L brewlength :lol: :lol:

Mind you the Scottish heavy I did last year had more grain than that but not the IBU's :lol: :lol:

 

[graysalchemy]

I could do you a 2l placky bottle if that suits...?

I haven't got a big enough cuach for that :rofl: :rofl:

 

[Brewberoza]

My question may be better posed like so:

If a recipe calls for say 30g bittering hops @ 10% AA and my hops are 12% AA I will have to use less and can calculate how the right amount for a consistent IBU.

But ...

What if instead the recipe calls for 30g late hops @ 5%AA but I have 6%AA?
Since these are NOT used primarily to add bitterness can I ignore the alpha acid designation and just use a consistent weight for aroma and flavour regardless of alpha acids?

 

[graysalchemy]

interesting question basically is aroma directly proportional to AA. :hmm: :hmm:

Don't know I usually just bung it into my brew software and see what it says. :hmm: :hmm:

 

[oz11]

Pretty much. I tend to regard bitterness units as a useful guide rather than an exact science. There are many variables involved in the calculation of IBUs which at homebrew scale you'll struggle to repeat from brew to brew.

 

[calumscott]

What if instead the recipe calls for 30g late hops @ 5%AA but I have 6%AA?
Since these are NOT used primarily to add bitterness can I ignore the alpha acid designation and just use a consistent weight for aroma and flavour regardless of alpha acids?

You can ignore the AA%, bitterness added by late addition hops is minimal (unless you use some monster like Warrior at 17%).

What you have to work out is the flavour and aroma profile of the hops - you would get a very different beer swapping Fuggle at 5.5% with Cascade at 7ish%.

This is the fun end of brewing, working the flavour potential of the hops...