Calculating loss of AA in stored whole hops?

cweston · 12-07-2006, 06:09 PM

Is there any formula, other than flat-out guessing, for estimating what the drop in AA% is after whole hops have been in the freezer for a certain time?

I bag hops in 1 oz portions when they arrive, then put the 1-oz bags in larger freezer bags and put the whole thing in the freezer. I try to adjust what the AA% might be a month or two months later. Anyone have anything better to go on than just guessing?

zoebisch01 · 12-07-2006, 09:20 PM

Boy, I am not sure that there is a formula. I would guess, however, like most things it is a decaying exponential, or at least that would give you a ballpark. So I think most of your loss will occur in the short term, followed by a more gradual loss. It would be different for all hops. It would be temperature dependent. It would also be dependent on the air infiltration. I would also imagine the rate of oxidation would be affected by the compactness of the cones, moisture content, etc. I am just guessing though.

**Brewpastor** · 12-07-2006, 09:42 PM

There is something wrong with "AA" in a posting on a brewers forum. "Hi, my name is BP, I make beer..."

**Baron von BeeGee** · 12-07-2006, 11:11 PM

Promash will calculate this for you (given months and temperature), but I'm not sure which formula they're referencing.

**david_42** · 12-08-2006, 12:31 AM

If the hops are frozen, there will be very little loss. You can get some idea by looking up the hop here http://www.freshops.com/usda_hop_desc2.htm, but most of the time they just say poor, fair, etc. and the ratings are for room temperature.

STORAGE STABILITY: very good, 30% transformation after 6 months room temperature storage.

Another joker in the pile, high beta acid hops will balance out the decline of the alphas by the betas becoming more available.

I have some Columbus pellets (I bought 2 pounds) in the freezer that are 18 months old & I haven't noticed any change.

**Hopfan** · 12-08-2006, 01:13 AM

Age decay will be most of the problem, but you can eliminate the air infiltration side of the equiation by using a FoodSaver to vacuum pack them. I have one of these that I use for long term meat storage and I also use it for hops to keep them relatively fresh when I buy a large quantity. They can be had for well under $100 and you can get the accessories for drawing oxygen out of wine bottles and the cannisters for marinating meats work great.