how to calculate the IBU's of 2008 hops?

I just bought an all grain setup from someone getting out of the hobby. He gave me all of his grain and hops as well. the hops were purchases in balk, repackaged in 3.5 oz. vacu-sealed bags, and frozen until now. I put them back in the freezer right after I got them. Anyway, is there a formula to calculator how much the hops have degraded over a year or 2, in-order to accurately calculate the IBU's? I understand beer smith has a calculator for this but it's not compatible with Mac. However if beer smith does have a calculator for this there must be a formula to manually account for this.
Here is a list of what hops and aa% I acquired.
GR. Magnum, Glacier 4.8%, US Hallertau 3.1%, Cascade 5.8, Columbus 16.8, EK Golding 5%, Fuggle 4.2%, Chinook 12.8%.

Thanks, Aaron

I believe this is done in a lab. It would be best just to estimate their Alpha Acid% based off of the type hop.

Also one farm may produce a Cascade hop with a high alpha and another farm could grow the same species with a lower alpha.

If you knew where the hops were grown, and the year you could probably find out their alpha acid%

IXVolt said:

I believe this is done in a lab. It would be best just to estimate their Alpha Acid% based off of the type hop.

Also one farm may produce a Cascade hop with a high alpha and another farm could grow the same species with a lower alpha.

If you knew where the hops were grown, and the year you could probably find out their alpha acid%

Click to expand...

aaron4osu gives the AA%, he wants to know much of the bittering has diminished.

I’m not sure how to calculate it. It seems like it would depend on a few different things though: leaf vs. pellets, type of hop, and condition stored in.

I recently bought a bunch of whole leaf hops when I was in Chico CA and I was surprised to see how fast they faded even when kept in the freezer.

they were leaf hops, vacu sealed and kept in the freezer. I'd Imagine there is % per year that I might be able to multiply by the IBU's. In my first two batches I just aimed for the higher of the ranges assuming it was going to be a little lower, but if hop oils degrade at say 5% or 25% that is a substantial swing in the IBU's. As I'm just getting into this and don't have a nose for hops yet I have no idea what they should spell like. I have pounds and pounds of different hops that I basically got for free. I can't see paying for hops while I have this surplus right now. If I can't figure this out I'll keep guessing, but it sucks because I can't really track and fine tune a recipe if I have no-clue what the IBU's are.

If the hops have been in storage below freezing temperatures in a vacuum-sealed container impervious to oxygen, the amount of degradation of alpha acids is going to be small enough that you won't notice a difference.


BTW, there's a section in Designing Great Beers that covers this topic in more depth and has a table showing degradation based on variety and storage temperature over a one-year period.

To find the current IBU's. You would need to know the HSI, or %alpha lost in 6 months. The default HSI that beersmith uses is 25%, so if we consider that to be conservative?

And the fact that they have been stored air tight in a freezer for 1 year.

This is what BeerSmith calcs the % Alpha at.
Glacier 4.3 %
Hallertau 2.8 %
Cascade 5.2 %
Columbus 15.2%
EK Golding 4.5%,
Fuggle 3.8%,
Chinook 11.5%

Download BeerSmith, do so right away. There are lots of reasons why it'll payoff, but one is it has a tool for calculating actual AAU based on original AAU, time stored, type of container, and time stored.

It's free for 3 weeks or a month, after that it's only $20 & it's amongst the best brewing $20 I've ever spent.

mkling said:

Download BeerSmith, do so right away. There are lots of reasons why it'll payoff, but one is it has a tool for calculating actual AAU based on original AAU, time stored, type of container, and time stored.

It's free for 3 weeks or a month, after that it's only $20 & it's amongst the best brewing $20 I've ever spent.

Click to expand...

Beersmith doesn't work on Mac...