traditionally dry ice(solid state of CO2) has been used in the "redneck" long term storage process from at least back in the 60's... I probably fit the term, even though I went to a reputable school in the South... does anybody have a technique for doing a single bucket at a time storage?...pruging with nitrogen or CO2 from a gas cylinder?...I'd like to do a full bucket of popcorn after I freeze the corn to kill off any weevil eggs...using the vacuum sealer is not volume efficient..

Why not just use dry ice?

Put a fist-sized lump in the center bottom of the bucket, add your popcorn to within an inch or so of the top, put the lid on put slightly ajar to vent. After 20-30 minutes, feel the center bottom of the bucket for cold. If it's still cold, some ice is still there. Continue to feel it until the center isn't cold, then seal the lid. Watch the bucket for several minutes -- if it starts to bulge, release the lid on one side for a few minutes. Seal and watch again. When no bulging occurs, you're done.

Sue

Sue... that will probably be my solution...my local source of dry ice has a minimum purchase anyway

That lid will release its self if the dry ice is still in there ! POP ! I can see a comedy skit in that (Ha Ha)!

You may need to check that the dry ice doesn't "burn" any food that it is in contact with. When I've used it in the past, mostly for meat storage, we always wrapped it in paper to stop this happening.

But dry ice would be an interesting comparison to the hand warmers. By the way, you can store dry ice for a few days in foam box in a domestic deep freeze – it won’t keep too long, but if you don’t use it all immediately you can prolong its life a little.

I'm not so sure about using dry-ice. The intense cold might trap moisture by converting it to ice or liquid that can't be pushed out by the sublimating CO2.

Dry ice is pretty easy to get. You can buy it here by the pound at many grocery stores. But, you can also get CO2 from most any welding supply house. It is pretty cheap. A simple rig with a rented tank, regulator, and hose would be easy to use.

You are right about the dry ice, it may cause condensation. If you do use CO2 and blast it in, the expanding gas can absorb heat from the environment and cause freezing too, so you need to go slow when adding liquefied gases.

I understood that dry ice sublimates directly from -100°F to a gas, and doesn't go through a moist stage. Is this incorrect?

It's been used for food storage for a long time. You'd think the word would have gotten out if it caused dampness and mold.

Sue

You are correct saying that CO2 in the form of dry ice doesn't usually have a liquid phase. Not that that matters much because dry ice does not contain any water and does not speed of support decomposition.

But the air already in the contained certainly has some percentage of water. And when dry ice is introduced the temperature into the air around the dry ice drops, which causes the moisture in that air to fall out and form condensation. This condensation isn't going to be forced out by the CO2 liberated as the Dry ice sublimates.

If you could introduce the CO2 into the container without markedly dropping temperature, you would better remove both oxygen and moisture.

Is that a desirable goal; depends. If you are packaging food in a low humidity location, a northern state in the winter, it might not make any difference because there isn't enough humidity to worry about. On the other hand, if you are packaging food in the south in summer, with humidity pushing 100%, it may make a big difference in how long the food lasts.

That dry ice has been used for years like this isn't much of an argument in my book. So far most people using this technique are reporting they get 'good' results. After a few years the food comes out in good shape. The question is whether this is as good as it gets. If they get good results at five years who is to say they might not get ten years if they used gaseous CO2 instead of solid CO2.

It also has to be noted, based on informal search on my part, that many of those using dry ice are in states with presumed lower relative humidity. Methods that work well in Arizona might not work so well in semi-tropical south Florida.

Okay, I see. Thanks for the explanation.

Sue

Its much ado about nothing, there is not enough water in the air in the bucket to affect the wheat (increase the moisture past 10%)
I'll leave the calculation for the skeptic.