Preserving food using CO2

[vt800c]

I see alot on how you should preserve foods in an oxygen free environment. I was wondering if using CO2 would work.

My thoughts were to prepare a bucket (or container) of loose grains or dried beans, and then put some dry ice on top. Because CO2 is heavier than air, it would decend into the bucket and force all the oxygen out the top. then before the co2 sublimes completely you can cover it and seal it.

The only concern might be from the frost or fog that the CO2 would draw out of the moisture in the air. maybe that can be minimized by putting the dry ice in a bowl OVER the container, and letting the CO2 use gravity to fill your bucket.

Any thoughts? Anyone ever hear of this or try it?

[dorminWS]

I know some higher-end vacuum baggers can be set up to inject a mixure of nitrogen & CO2 into a bag to protect the contents from being crushed by air pressure - so there is partial pressure but no oxygen in the bag. I'm not sure why they mix nitrogen & CO2, though. I also know that when disolved in water, CO2 is acidic - again, not sure about the pure gas, but I assume that unlike nitrogen, CO2 is not inert - i.e., that it might react in various ways with the food. But all that is just somewhere between informed surmise and an out-and-out CWAG. Fact is, I hope somebody can tell us BOTH for sure. CO2 is a lot easier to come by than nitrogen.

It does occur to me that storing buckets full of hoarded grub and CO2 in a confined space may involve some risk. Like carbon MONoxide, it is heavier than air and will kill you in high enough concentrations if it should ever leak out of the buckets and fill up your basement/bunker.

[ShotgunBlast]

I guess that's one way to do it, albeit a more costly way. Most people stick with oxygen absorbers or vacuum sealing. Those methods seem to work just fine for your dry goods.

[WRW]

Yeah, absorb the oxygen and nitrogen is about all that is left.

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[SpanishInquisition]

Nitrogen can't be metabolized by any animal or plant critters, so if you're hellbent on gas-filling for food preservation, it's the winner.
I'm pretty sure you can get pony bottles just as you would CO2 for homebrewing. In addition to welding supply places, you can also get smaller spray cans of N2 at wine shops.

By putting dry ice in the bucket, you may well pop the top off before you displace air (assuming you seal it down as part of your process).

Nitrogen is also safer to SOME degree because if you ever do the darwin-failing "stick your head in the gas filled bucket and breathe deeply" trick, nitrogen won't send you into convulsions like carbon dioxide can. You could still die, but it'll be less hilarious to those observing.

[dorminWS]

Yes, but whether you use CO2 or nitrogen, I'd think you ought to be sure it's FOOD GRADE. I'm not sure all bottled gases are. A welding supply shop may not meet that requirement. If I were going to use dry ice, I would but it in a small dish, put the top on, and let it evaporate before sealing. That way the excess can escape. Also, I'd think you'd want to do it in a very well dehumidified place.

[SpanishInquisition]

If you've ever had homebrew beer from a keg, you have been exposed to CO2 from the same source as welders. Gasses are pretty darn pure from any source you can buy from.

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[dorminWS]

Food grade gases are subject to certain procedures designed to assure against adulteration. Non food grade are not. If I were packaging SURVIVAL rations for long-term storage (and therefore long-term exposure to the gas), I'd think it was worth those assurances. I could tell you about one or two instances of adulteration even of food grade ingredients. I could also tell you about deliveries of food grade ingredients that were delayed because the aforementioned procedures caught an adulteration before distribution and created a shortage. By the way - I believe the the most common adulterative agent for CO2 is oil from the compressors that liquify the gas. I've also been given to understand that CO2 is almost always captured as a by-product of the production of other (usually chemical) products (fertilizer is a biggie); and those primary products can have an effect on the suitability of the CO2 for food use. Non food grade ingredients are more likely to be adulterated. But you're right; they're pretty safe - most of the time. I just figure it's a lot smaller problem to dump out a keg of homebrew than to wake up the morning after armageddon (or whatever) to a nuclear winter (or whatever) and a spoiled food cache.

[JimS]

Ready Reserve Foods sells a nitrogen kit, mylar sacks and 5 gallon buckets.

http://store.readyreservefoods.com/inde ... uct_id=181

They are out of stock now but they usually have ammo prepacked in nitrogen.

Jim

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[meadmkr]

Simpler is better, I'll stick with O2 absorbers in sealed mylar in a bucket/bin to protect the mylar from being punctured.

[Karnivore]

agree with the mylar and 02 absorbers, in the buckets

[UnderwaterMike]

Use nitrogen. You don't want a non-intert gas in prolonged contact with food if you can help it.

In addition, on the slim chance that you got any moisture trapped in your bean stash, a CO2-rich environment is going to aid sprouting. So, unless you want spouts for a salad or something, stick with nitrogen.