# Hops alpha stability



## The Judge (24/11/15)

I noticed on some sites about hops they mention the _storage stability_ of hops.

For example this page on Columbus says that after 6 months of storage only 52% of alpha acids are (I presume) isomerisable.

That seems like complete arse to me, as I've used stored hops from 3 years ago and my calcs of IBU have been based on what's reported on the packet at time of packaging - and I've not noticed significantly less bittering. i.e. I don't adjust the recipe by dumping in 100% more hops to account for decreased alpha acids.

Is this actually a thing to be concerned about? I thought it was aroma which was affected by staling.



Proof is always in the drinking, but if I want my calcs to be correct, should any corrections be made?


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## Black n Tan (24/11/15)

That is when stored at 20C; it will be a fraction of that in the freezer.


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## Mardoo (24/11/15)

I believe those figures assume room-temperature storage. Someone correct me if I'm wrong.


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## danestead (24/11/15)

As said above, thats at 20 degrees c and not vac sealed etc.

There r calculators online and generally in brewing software to calculate what your AA% will be after storing for a considerable time. I always adjust my AA's as it makes a big difference when your hops are a few years old. These calculators are a bit like a yeast starter calculator though, its all a hit of a guesstimate. Ive not really experienced overly bitter beers due to adjusting the AA's and in my opinion the adjusted AA is likely closer than the original AA.


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## antiphile (24/11/15)

Have to agree with everyone above. If you do a search using "Beersmith HSI" (standing for Hop Storage Index), you'll get a lot of information.


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## The Judge (24/11/15)

Righto - thanks. I've never even considered this (except when harvesting my own hops). And what's more, I've never noticed a difference in calc'd vs actual bitterness. I guess cos most of my hops are stored pretty cold.


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## Danscraftbeer (24/11/15)

Also the notes of different hops in the software and specs elsewere.. Some hops have much poorer storage ability over time and I believe it from experience. Aroma hops for eg. So low in AA that's all lost with the Aroma as well. Not much good for those 18+ months old that I can think of. I don't even know if the worms would like it in the compost. :unsure:


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