Adjusting for Alpha Acid % Loss Over Time

[Holybarfly]

Do you guys account for alpha acid loss for old hops when building recipes and calculating IBUs? I am planning a recipe with some 2013 UK Challenger and EKG that are still sealed in mylar, which I purchased last month. They have been in my freezer.

Research has yielded me:

http://morebeer.com/brewingtechniques/library/backissues/issue2.1/garetz.html

http://beersmith.com/blog/2008/04/15/brewing-hops-storage-preserving-precious-hops/

http://brewerslog.appspot.com/HopAlphaCalc

Beersmith and, particularly the calculator, seem pretty extreme in terms of AA loss. Forum posts from various sources, including here, regularly list 10-20% AA loss per year.

Is 15% (7.5% per 6 mos) a good middle of the road compromise, assuming hops are being vaccuum sealed and stored in the freezer? I'd like to keep by BU/GU balance intact.

 

[day_trippr]

I think 15% AA loss is a viable SWAG - for a year in the deep freezer in a barrier vac bag.

I actually do that math as I'm still finishing up some 2013 homegrowns...

Cheers!

 

[schokie]

I don't adjust at all for hops still in a sealed Mylar bag that have been in the freezer. Once exposed to O2 the hops will start to degrade. So if you open the bag, use hops, seal the rest back up, and return to the freezer, you'll probably lose a little bit in there. Bt not enough to bother adjusting for. Certainly not over a timeframe of a few months.

I question some of those acid loss claims. What are their assumptions? I just can't see that much loss from something that's in a deep freezer.

All this begs the question though, why aren't you going through your hops quicker? Mine don't last long enough for AA loss to be an issue.

 

[shelly_belly]

I find that the losses from old hops that I have used are more in the flavor and aroma aspects than in the bittering properties. Whenever I have increased the bittering hops due to aged hops my beers came out too bitter. I now make adjustments such as an additional x 5% in the flavor range and an additional x 10% in the aroma range per year of age on the hops, with no adjustments on the bittering additions. I try to use the current years crop for dry hops, if not, an additional x 50% for 1 year old hops.

 

[Holybarfly]

I don't adjust at all for hops still in a sealed Mylar bag that have been in the freezer. Once exposed to O2 the hops will start to degrade. So if you open the bag, use hops, seal the rest back up, and return to the freezer, you'll probably lose a little bit in there. Bt not enough to bother adjusting for. Certainly not over a timeframe of a few months.

I question some of those acid loss claims. What are their assumptions? I just can't see that much loss from something that's in a deep freezer.

All this begs the question though, why aren't you going through your hops quicker? Mine don't last long enough for AA loss to be an issue.

It's not really a matter of going through the hops quickly, as these are 2013 import hops. We don't have 2014 available to us yet.

 

[Holybarfly]

I find that the losses from old hops that I have used are more in the flavor and aroma aspects than in the bittering properties. Whenever I have increased the bittering hops due to aged hops my beers came out too bitter. I now make adjustments such as an additional x 5% in the flavor range and an additional x 10% in the aroma range per year of age on the hops, with no adjustments on the bittering additions. I try to use the current years crop for dry hops, if not, an additional x 50% for 1 year old hops.

This is exactly the insight I was looking for. Thank you. I just had sort of a lightbulb moment when looking at the ~9 lbs of hops in ny freezer. I've never bought in bulk before.

Now to develop my own anecdotal evidence!

 

[day_trippr]

[...]All this begs the question though, why aren't you going through your hops quicker? [...]

Such a simple question deserves a simple answer: it's barely a couple months past the 2014 harvest, and many of us buy in bulk for ~November delivery...

Cheers!

 

[schokie]

You mean you buy a large bulk of hops right after harvest instead of 1-2 lb periodic purchases throughout the year? I never thought of that. Do the major homebrew hop distributors go through their supply often enough for that to work? Who do you bulk order your hops from?

 

[day_trippr]

You realize, of course, that the bulk of all the hops sold throughout the year were harvested roughly within a month?

I buy from whomever has good product delivered at a competitive price in a timely manner, and as I regularly use a number of strains it usually means buying from a few of the larger retailers.

But in any case I buy pounds just as soon as the strain is available. The savings over the alternative can be dramatic, and I like having environmental control over the hops as early as possible...

Cheers!

 

[schokie]

You realize, of course, that the bulk of all the hops sold throughout the year were harvested roughly within a month?

It sounds so obvious now. I guess it's one of those things I haven't given much thought too. You bring up great points. Now I have to rethink my entire hop existence!

 

[Calder]

Beersmith and, particularly the calculator, seem pretty extreme in terms of AA loss. Forum posts from various sources, including here, regularly list 10-20% AA loss per year.

Is 15% (7.5% per 6 mos) a good middle of the road compromise, assuming hops are being vaccuum sealed and stored in the freezer? I'd like to keep by BU/GU balance intact.

They don't loose that much. Per BeerSmith calculator:

UK Challenger: 5% loss in 12 months (from 7.5 AAs to 7.13 AAs) when stored vacuum packed at 0 F.

EKG: 7% loss in 12 months (from 5.0 AAs to 4.64 AAs) when stored vacuum packed at 0 F.

I think you might be looking at the calculator wrong. The HSI number quoted is the 'Hop Storage Index', and is the amount of AA loss you can expect when the hops are stored open to the air at 70 F. The HSI varies for different hops. Exclusion of O2 and cold temperatures reduces the loss/aging.

 

[Holybarfly]

They don't loose that much. Per BeerSmith calculator:

UK Challenger: 5% loss in 12 months (from 7.5 AAs to 7.13 AAs) when stored vacuum packed at 0 F.

EKG: 7% loss in 12 months (from 5.0 AAs to 4.64 AAs) when stored vacuum packed at 0 F.

I think you might be looking at the calculator wrong. The HSI number quoted is the 'Hop Storage Index', and is the amount of AA loss you can expect when the hops are stored open to the air at 70 F. The HSI varies for different hops. Exclusion of O2 and cold temperatures reduces the loss/aging.

Aha! I was interpreting it wrong. Thanks for the course-correction.

 

[Teromous]

I think 15% AA loss is a viable SWAG

What does SWAG stand for?

 

[Yooper]

While I don't recommend this as routine practice, I recently used 2007 hops from my freezer. I didn't notice any degradation at all, and the bittering was just fine. I think keeping the hops frozen, and vacuum sealed, and out of light really prolongs the properties.

I am using 2013 hops just as if they were 2014 hops at this point, with great results.

 

[Black Island Brewer]

What does SWAG stand for?

Scientific Wild Assed Guess

 

[Holybarfly]

While I don't recommend this as routine practice, I recently used 2007 hops from my freezer. I didn't notice any degradation at all, and the bittering was just fine. I think keeping the hops frozen, and vacuum sealed, and out of light really prolongs the properties.

I am using 2013 hops just as if they were 2014 hops at this point, with great results.

Great! I adjusted the 15% for yesterday' brew and I think it changed the IBUs by ~5-6, which is within the apparent tolerance range where we can't detect differences. I've brewed this recipe before, so well see of it comes out hoppier than usual.