Hop age AA calculator?

[donchiquon]

Hi All

Like most folk have a variety of hops that are not this years harvest, and have been stored either in their original vac pac or in the freezer resealed as best I can. Some of these have now been in the freezer for up to a year and a half, and others in their original packaging are as old as 2013.

Some of the AA% age calculators I have tried can quickly decrease the % by half, so I am starting to think I should be adjusting the % for many of my hops.

Does anyone have any general advice on % adjustment and recommendations for a simple calculator to work out AA% for hops?

Thanks in advance!
DC

[Sadfield]

I wouldn't worry too much if they have been well stored. The ability of the human palate to detect differences in IBUs is pretty limited, IIRC around 5-10 IBU increments and only up to around 60-70 IBUs. Hop aroma, and residual sweetness have a greater affect on perception of bitterness than actual IBU values.

Also, there's a brulosophy blog where fresh and well stored,10 year old Williamette hops were compared, with no real difference.

[Kev888]

In the distant past I somewhat naively tried compensating for AA reduction at around 10% per year, based on authoritative-sounding figures found on various websites. This clearly wasn't suitable for hops stored cold in foil vac-packs; it was far too much and my results were consequently far too bitter.

Storage temperature makes quite a difference IMO, and the way my hops (mostly from the malt miller) are packaged in foil, nitrogen flushed vac packs clearly works very well too. There is also a school of thought that although Alpha Acids break down, the Beta Acids slowly increase apparent bitterness as they oxidise, which offsets things to a degree.

More recently I've not compensated more than 2% per year. This amount seems to be below my ability to detect in the finished beer so with recent hops I don't bother much. But with older hops, a few years or more after harvest, the effects are cumulative and so more noticeable. Compensating by ~2% does seem roughly right for my storage conditions (yours may vary).

EDIT (again!) Just to update this old post: I found mention of 2% in a PDF on Faram's website, for cold storage this supports deterioration of 2%aa but thats before any affect of beta acids oxidising so even that may be a little much in practice for very well stored hops.

[donchiquon]

Thanks @Sadfield and @Kev888

Sounds like that is good news for both my aging hop stores and also keeping my brewing simple!

Possibly not such good news for my last (and sixth) attempt at a Landlord clone which I've now calculated will be nearly 10 IBU more than planned due to hop adjustment!

Thanks for the advice!

[FUBAR]

I well remember back when hops from the local HB shop came with no information on the clear plastic bag they came in, they where always bone dry and I used to add them without question as per the Dave Line recipe. It worked reasonably well considering everything .

[vacant]

It amuses me to read the AA on the packs of hops. Given to 0.1% accuracy? Really? So there's no variation between hops from different parts of the plant (maybe), different parts of the hop field, different fields, different dates throughout the harvest?

[Bazz]

It amuses me to read the AA on the packs of hops. Given to 0.1% accuracy? Really? So there's no variation between hops from different parts of the plant (maybe), different parts of the hop field, different fields, different dates throughout the harvest?

You have a point i suppose, i'm guessing that they use an average from various cuttings that are tested in a lab.

[Kev888]

Yes, the %AA figure is not for the specific pack. Although apparently mixing prior to processing/packing makes the hops considerably more uniform than I once feared.

There are other variables too. Apparently different labs/analysis can give different test results, there are all manner of factors which affect our utilization and our perception is far from uniform or linear as well as being influenced by accompanying flavours from malt and water chemistry etc. IMO one may as well use the values given (typing a decimal place is hardly any effort), but it is worth remembering the complexity of the context before getting too hung up on minor subtleties.

[vacant]

Rather than a percentage AA for hops, I propose "low", "medium", "high", and "11"

[Jim]

Agree with the above posts - I keep my hops in the freezer and have not noticed any deterioration even after a couple of years.

As also said above, don't get too hung up on the decimal points - hopping and bitterness for home brewing is not an exact science by any means.

[donchiquon]

That's all reassuring. Nice not to have to worry about another thing on brewday!