Storing Hops Frozen

[PMR]

Hey all--

I had a fellow brewer friend visit my brewery today and he commented on my storing of hop pellets in a chest freezer that's set at -10F. He said this would fracture hop oils and weaken the hop aroma, and suggested refrigeration at 40 degrees or higher. I've been very happy with the aroma of the hops I've been using and can't imagine why this would degrade the hops more than conventional refrigeration, especially with the moisture issue with normal refrigeration. I don't know everything (or all that much) about this topic, so I thought I'd get your opinions on this. Thanks!

[Øl-sheik]

Well, that is quite a wrong info from your fellow brewer. You store the hops just perfectly at that very cold temperature. Big hop merchants, at least here in europe store the hops at -22 Fahrenheit to garanty you the highest quality possible.

Oil and hop acid oxidation are triggered by the partial pressure of oxygen present, temperature and light. If one of these parameters goes up, then the storability goes down. So store it away from oxygen, dark and freezen cold :-)

Prost

[Woolsocks]

I'm no expert on hop storage either, but this would be the first I've heard that freezing is bad, and I've read many many times that colder is better.

[James Altwies]

The essential oils of hops are very stable at those temps. and would need to go much much lower to experience any fraction crystalization. I'll take a look at the general chemical structures this weekend and get back to the boards.

[gitchegumee]

I'll bump this thread to find out whether anyone has heard anything different from the last three posters. I would agree with them, but all my textbooks and other references recommend storage at 0-3C. It could very well be that 0-3C is the sweet spot for larger concerns that don't want to store any colder than absolutely necessary to save on electrical costs. I simply don't know and I'm about to contract storage of hops at -20C. Is that too cold? Thanks for any help!

[liammckenna]

Back in the early 90's, I worked for a 20 000 hL micro. After arranging our hop contract, a few weeks later, much to my surprise, the entire contract arrived.

I had arranged to withdraw as needed but somehow the communication got garbled. Through the jigs and the reels, the supplier agreed to cover the local storage fee (which wasn't that much as it occupied a single pallet space).

Across the road was a freezer storage facility. We stored those hops, some for more than a year, at -20C. I noted no degradation of oil/flavour/aroma and our alpha's and BU's did not suffer at all. These were regularly tested in our own lab.

Another observation.

Pax.

Liam

[gitchegumee]

Thanks Liam. That's what I wanted to hear. Cheers!

[Woolsocks]

I'm pretty sure most hop brokers store them at about 0°C or a little higher. From this thread, it sounds like I ought to rent some "freezer" (-20°C) storage space and have the entirety of my hop contracts shipped to said freezer space.

This might actually save money, too, since I'd be paying for one big shipment from the hop broker instead of many small shipments. Might offset the freezer rental anyway.

Another upside would be that on those occasions something goes wrong with the brew schedule and I need hops quick, I could run down to the freezer space and get them instead of paying for expedited shipping!

Thoughts?

[liammckenna]

I'm pretty sure most hop brokers store them at about 0°C or a little higher. From this thread, it sounds like I ought to rent some "freezer" (-20°C) storage space and have the entirety of my hop contracts shipped to said freezer space.

This might actually save money, too, since I'd be paying for one big shipment from the hop broker instead of many small shipments. Might offset the freezer rental anyway.

Another upside would be that on those occasions something goes wrong with the brew schedule and I need hops quick, I could run down to the freezer space and get them instead of paying for expedited shipping!

Thoughts?

I would have thought brokers would store them colder to preserve them. I honestly don't know.

I guess it (economically) depends on the fee for rental of the space (freezer storage).

They'll definitely be more accessible to you.

Interested in the results of your investigation....

Pax.

Liam

[Woolsocks]

My hop guy says 28°F storage is all that's needed.

[liammckenna]

My hop guy says 28°F storage is all that's needed.

Interesting (if aging) read here.

Don't know how sound the authors assumptions are but I think I can get my hands on copies of the cited J. Inst. Brewing source articles from the bibliography.

Pax.

Liam

[porter]

For what it's worth...

At CBC in San Diego last year I was in a seminar about hops and the question of storage temp came up.

If I remember correctly, there was one panelist that worked for a hop broker (hop union?) that said the optimum storage temp for pelletized hops is 26F.

Anything higher would cause faster degradation and anything lower is a waste of energy/money.

[WVStartup]

For what it's worth...

At CBC in San Diego last year I was in a seminar about hops and the question of storage temp came up.

If I remember correctly, there was one panelist that worked for a hop broker (hop union?) that said the optimum storage temp for pelletized hops is 26F.

Anything higher would cause faster degradation and anything lower is a waste of energy/money.

I know that a lot of the big hops storage facilities aren't sub-zero. I've been in a few, and this is pretty typical: http://www.yakimachief.com/facilities/storage.html
Wasting energy is a good point, but I think that a lot of brewers that are storing a moderate amount of hops are just putting then in an existing freezer. No harm done and it's an easy way to store them. But keeping them in the 28*F range would save you a few bucks, assuming you have the ability to adjust to those temps and don't have to worry about any other products being too warm.