Freezing coffee should always be done with vacuum (freezing + vacuum). Otherwise, who knows what odors the beans pick up. Also, if you don't vacuum, the humidity may change. Air from a refrigerator/freezer is bad for the beans. The higher the storage humidity, the shorter the life span. The reason why people find differences freezing coffee has to do with vacuuming.

Cheers

I'm not sure if he meant a sealed container or vacuum evacuated, as in the removal of as much air as possible from the container. Vacuum evacuation might help by removing reactive oxygen or the moisture content of air from the container.

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HB wrote:Since the seal in both cases is airtight (and in the former case, the bag is filled with CO2), I don't see how vacuuming would help.

Nope. I guarantee that you didn't seal anything. The seals from a coffee bag are not really sealed (they are to the eye), neither the one from a piece of tape. A coffee bag is not as good as a vacuum bag. That is like wrapping coffee beans with paper towels (you don't see the beans).

I meant using a canister or bag with 28 inches of Hg (vacuum).

Cheers

And your evidence establishing this fact is . . . . what?

Mind you, I don't care about the specific physical environment you seem to be seeking for your coffee as it reposes in the freezer. What I care about is the evidence that you have that this environment you prefer, has any tastable effect on the coffee once defrosted and used.

The freezing experiments written about on this website used standard plastic coffee valve bags with a piece of tape placed over the valve. No vacuums or gases were used. For my own use, I use mason and other semi-airtight glass jars. Are they hermetically sealed? NO. Does it matter? I sincerely doubt it. Could I be mistaken? YES. Would I insist on some type of proof that I was wrong before going out and buying vacuum equipment? YES.

ken

Hi Ed.

I don't have science to prove it, as it is not my intention to prove it. It is just only my opinion.

The bags I use have 5 + 1 layers. There must be a reason why they (Foodsaver) use so many layers. Not all vacuum/freezing bags are equal and neither are the vacuum sealers, and probably not all coffee bags are made equal either (even same brand and same model). Not all one way valves are equal, even same brand and model. Not all seals are equal, even when using same machine and same bags. All bags cannot be abstracted as being "equal" as some will leak more than others (bad seals). Freezing coffee may not be as dramatic as freezing for example steaks, since the coffee has much less moisture. But I think it should be treated like a steak or fresh food. Freezing could cause freezer-burn in a small proportion (surface) or gaining odors. Very little leaks behave as huge leaks during long freezing periods.

Cheers

Not Ed but --

I have used 3 different types of coffee valve bags over the years. I have also used foodsaver bags for freezing green coffee, but no longer use them.

2 of the coffee valve bag types I've used were a single layer of clear plastic. These have held up very well even over periods of several months. They puff up nicely when removed from the freezer, and also to a small extent after a little while in the freezer, indicating (to me) a pretty good seal. The multilayer laminated metallic coffee valve bags I have don't freeze well. They crack and leak. So I stopped using them after the first few times.

Foodsaver bags, in my experience, when used for freezing green coffee, develop pinholes in the freezer and what went in as a tightly formed brick hugging the green beans is usually removed with obvious air inside of it and no longer form fitting. I think they are not designed for freezing rigid items like coffee beans. I use double bagged freezer ziplock bags for my green beans now.

I can see no logical reason why a multilayered bag would be any better in the freezer than a single layer bag that is thick enough. My own personal experience is that a thick single layer bag is better.

ken

RapidCoffee wrote:Speak for yourself.

I'm fully aware of the source of my quote but can see that the citation wasn't clear - thanks for pointing that out and providing the opportunity for me to clarify. My intention was to reinforce the point that Ken's resultant recommendations were fairly specific with regard to instruction and process; IF you follow those recommendations, your results may be similar.

I'd think that a quick inquiry into the freezing procedure (for serious eats) can shed some light on this topic.

-s.

My apologies Ken (not Ed)!

I understand your point of view and opinion. Do what ever it works.

But I think people "contaminate" frozen coffee and attribute the bad results to freezing instead of bad practices. That would explain the inconsistency of opinions as it is easy to "contaminate" frozen food when not prepared properly. Some people are just more careful than others. This extra attention plays an important role when the freezing time is longer. Roasted coffee should be ideal for freezing as it has very little moisture.

Cheers

I don't know what you mean by contaminate. Contaminate by what? Freezing is really super simple. Put beans in clean dry mason jar. Screw lid on tightly. Toss in freezer. Done!

Jars pop nicely when you take them out and open after they come to room temperature... I don't see what is complicated there and where "contamination" is introduced. Mason jars hold very tight seal in my experience.