Hop alpha acid loss over time

[Toxophilly]

Hi all,

I came across this calculator which purports to calculate the alpha acid loss of hops over time: http://brewerslog.appspot.com/HopAlphaCalc

In my case, I have an unopened pack of Galaxy at 13.7% AA from the 2016 harvest. 2016 harvest is decent compared to some hop packets I've seen.

I gather the Australian hop harvest is in March and it's March now, so I enter 365 days old into the calculator; that it's "Sealed in barrier packaging, airtight jars [foil pack] under vacuum"; and I can't guarantee the homebrew supplier kept them refrigerated so I put in 21 degrees C as the storage temperature.

Based on this, the calculator tells me the hops now have 4.5% AA. I suspect if I were to adjust my recipe accordingly and pile in loads more hops to hit the IBU I'd end up with a horribly bitter beer - the calculator's got to be wrong

Any thoughts on this calculator, and accounting for AA loss when designing beers or following recipes?

[k1100t]

I used Brewer's Lair Hop Alpha Acid Loss to calculate the losses on the old hops I used on AG #14 – Brown Dwarf: Amarillo, Chinook, Simcoe, Cascade. It had plenty of bitterness!

Cheers,

Bob.

[orlando]

Do you know what? I wouldn't concern yourself with this at all. Human perception of bitterness is very variable. The ability to discern a difference in one beer's bitterness compared to another is quite difficult within 5 IBU's. As long as your hops are stored "properly" just follow the recipe and see whether or not it suits you. For me I find an IBU:SG ratio is worth following. After many brews I have found a balance of .6 for an average strength beer suits me perfectly so I ignore what the IBU level is completely. Once you get to stronger beers that changes a little and if you want a malt forward beer you might get closer to .5.

Bitterness is the one thing that really is hard to pin down out of all the parameters we juggle with and frankly worrying about it doesn't change a thing.

[chefgage]

I use the calculator on beersmith for older hops to give the new aa. Not sure how this compares to just ignoring the calculation and just putting in the hops required by the recipe. I dont brew often enough to do any experiments but the beer turns out with what I think is ok bitterness wise so i am sticking with using the calculator.

If i get time later i will put your values in beersmith to see what it says.

[scuppeteer]

That calculator is proper messed up.

You haven't said if you have leaf or pellet. Pellet does degrade quicker but certainly not by that much in a year.

Trouble is everyones kit is different so utilisation will differ anyway. As a personal rule I rarely use anything over 10% for bittering. If I do then it'll be FWH. Vac packing will preserve them far better whatever conditions they are kept in. As Orlando said bittering is very much perceived on the individual.

[Toxophilly]

Thanks for all the replies. They are whole leaf hops - and they're boiling away behind me as I type this.

In the end I used Beersmith's Hop Age tool - I hadn't realised Beer Smith had this feature when first posting - which took the Galaxy to 9.23%. Appreciate the comments on bitterness subjectivity and that little differences won't matter a great deal.

Primarily at the moment I'm trying to hit numbers and be a bit more precise with my brewing, hence my interest in this.

[orlando]

Primarily at the moment I'm trying to hit numbers and be a bit more precise with my brewing, hence my interest in this.

You're quite right to do this first, nothing like your own experience for informing you about what is true and what is, well, shall we just say not.