Hop alpha acid different to recipe

[AnimatedGIF]

Hello,
I am brewing Greg Hughes Yorkshire Bitter (p141 2019 edition), scaling down to 5L stovetop.
I have First Gold hops that are 5.6%AA, rather than 8%. I think Iunderstand that with bittering hops, one would adjust to achieve the equivalent IBU, however these hops go in the end (flavour/aroma?), so do I still need to correct to get the same AA or not?

 

[foxbat]

Hello,
I am brewing Greg Hughes Yorkshire Bitter (p141 2019 edition), scaling down to 5L stovetop.
I have First Gold hops that are 5.6%AA, rather than 8%. I think Iunderstand that with bittering hops, one would adjust to achieve the equivalent IBU, however these hops go in the end (flavour/aroma?), so do I still need to correct to get the same AA or not?

At the end (10 minutes or under) the difference will be undetectable. You can scale down based on the recipe volume difference alone.

 

[AnimatedGIF]

Great, thanks foxbat

 

[Sandimas]

I'm sure many brewers, myself included, only pick up on this late in their brewing careers.

Seen loads of recipes which state the quantity of hops e.g. 20g of Fuggles @60min, which means absolutely nothing without knowing the AA of the hops in order to achieve the target bitterness. I've had packets of certain hops that were half the AA of the previous batch.

Realising this, and then plugging the figures for the actual AA of the hops I have into the brewing software to achieve the recipe target, is one of the biggest improvements to my homebrew. I now do this every brewday.

 

[Clint]

A good point! Sometimes when the AA is vastly different I'll just use magnum as a bittering hop.

 

[AnimatedGIF]

I should probably look in to using brewing software. I've only used the calculators for things like priming and carbonation so far, having mainly done kits.

 

[PhilBrew]

Hi foxbat

At the end (10 minutes or under) the difference will be undetectable.

... I'm sure you're right in this instance, since the amount of late hops is likely to be relatively small in this particular beer ... but having checked with an experienced hop grower (on another brewing forum somewhere, who will have seen many more report on hop analyses than I ever have) I've been led to believe that the chemicals in hop flowers (of a particular variety of hop) will tend to stay in similar proportions, even though the overall amounts may change with different seasons/growing conditions ... so if the AA% is lower in one batch of a particular hop, over some other batch of the same hop variety, that will be a relatively good indicator that the amounts of flavouring oils will also be lower in those hops from that batch. As an extreme example, the AA% of UK grown Cascade may be 1/3 to 1/2 that of the US grown version, and you may need to add 2 - 3 times as much as late additions to get similar effects in a Pale Ale/IPA, say

Cheers, PhilB

 

[Benfleet Brewery]

A good point! Sometimes when the AA is vastly different I'll just use magnum as a bittering hop.

I do this too. However, BF has Magnum AA default at 15% whereas mine are 10% so I still need to adjust this.

 

[Horners]

Hi foxbat
... I'm sure you're right in this instance, since the amount of late hops is likely to be relatively small in this particular beer ... but having checked with an experienced hop grower (on another brewing forum somewhere, who will have seen many more report on hop analyses than I ever have) I've been led to believe that the chemicals in hop flowers (of a particular variety of hop) will tend to stay in similar proportions, even though the overall amounts may change with different seasons/growing conditions ... so if the AA% is lower in one batch of a particular hop, over some other batch of the same hop variety, that will be a relatively good indicator that the amounts of flavouring oils will also be lower in those hops from that batch. As an extreme example, the AA% of UK grown Cascade may be 1/3 to 1/2 that of the US grown version, and you may need to add 2 - 3 times as much as late additions to get similar effects in a Pale Ale/IPA, say

Cheers, PhilB

I'd often wondered this - good info thanks