Two months ago I brewed an ale with three hops - cascade, northern brewer and saaz. I immediately put them in the freezer, but want to know how to best use them (if there has been any degredation).

So, preferably (to make this a complete guide) I'd like answers to the following questions:

How does freezing effect

  • Aroma potential
  • Bittering potential
  • Flavor potential

in the following forms of hops:

  • Whole
  • Plug
  • Pellet

My hops were whole, and frozen 30 minutes after opening the vacuum bag (in the same bag, but no longer with vacuum). I've read that I should add 30% extra bittering hops. Does flavor/aroma potential degrade more/less?

There is a similar question on this site, but it asks what the best way to store opened hops is, but not if the effect of storage is.

  • 30% after how long of storage. The loss in potential is a slowly but constantly moving target.
    – brewchez
    Sep 15, 2011 at 19:31
  • @brew Two months of storage. Maybe 30% is alot, I'm just looking for general best practices. I mean, most if not all brewers must surely face this problem sometime... It standard practice to simply use them as ordinary?
    – Max
    Sep 15, 2011 at 20:16
  • 3
    Choosing Cascade hops at random, Promash shows that 6 months of storage at -10F (average freezer temp) reduces the AA from 5.75% to 5.35%. Not much.....
    – Denny Conn
    Sep 15, 2011 at 21:49
  • And Promash is up to date...
    – brewchez
    Sep 16, 2011 at 11:40

5 Answers 5


The freezer greatly slows degradation of the hops. I've never experienced any negative effects from storing hops in the freezer. It's the preferred method of storage. The absolute best thing you can do is vacuum seal them before storing them in the freezer. Barring that, using a resealable bag that you remove as much air as possible from will work well.


You questions are good ones, unfortunately the effect of storage is somewhat variety dependent. Some hops store better than others, so there is no definative answer there. I will say that the effect is not broken into aroma, flavor or bittering either, seeing how its all based on the storage effect on the gland of the hop. Aroma, flavor and bittering all come from the same place, its the boil time that really determine what you are getting from the hops.

In general, there may be some statistics out there that give the degradation rate of each variety under certain storage conditions. I haven't seen a clear chart or table with that data though.

I have stored hops in the opened mylar bag I got them in wrapped in a sealed ziploc in the freezer for a couple years and not really noticed a huge change in bittering potential.

30% figure seems high, but its time dependent too. The hops slowly loose their alpha potential with time. A month later you probably don't notice the change, a year later...maybe.


I think there is some great advice here but I listen to a lot of bodcasts and there is a particular Beersmith podcast called "hop chemistry" where James Altwies from Gorst Valley Hops gives some great info and mentions that they freeze their hops at an insanely low temp.

  • I heard that postcase, and I understood that the insanely low temp was mainly to preserve the aromatics, since they can become volatile at fairly low temperatures.
    – mdma
    Jul 11, 2012 at 15:21

Most varieties will safely store frozen for up to a year if wrapped tightly with low oxygen content. Beyond one year you will likely begin to see some degradation.


According to the hops book from the great Brewing Elements series, if you store your hops pellets in the freezer in a vacuum bag, it should stay usable for up to three years in general. Loss of alpha acid will occur, but not too much. This is not true for fresh hops, though. I store my hops in a freezer at -16deg C and vacuum it always after use and am pretty content with it. The key factors here are oxygen and temperature.

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