They both serve the same purpose.
No, not actually. Dry ice principal use is as a FUMIGANT.
The CO2 works by displacing the oxygen. A useful quality of it is that it is heavier than air (the mix containing oxygen) and forces most everything else out. Bugs can't live in an oxygen deprived/free environment, rendering your goods safe.
"Rendering your good safe" the dry ice acts as a FUMIGANT but over time, because you won't have any real oxygen barrier (the bucket is NOT a real oxygen barrier) you could HAVE OXIDATION OF THE FOOD with dry ice.
An oxygen absorber works by chemically binding the oxygen into rust, or ironOXIDE. One disadvantage I see to them for long-term storage is that they pull a vacuum in the bag. If you have a fold in a bad spot or a sharp place, this could cause a small hole. Maybe not an issue. The other thing is that your bag, which is permeable to air,
What bag are you using that is permeable to air? That defeats the whole purpose of packing this way. Unless someone is cutting corners doing stupid things like using trash bags, mylar party balloons or ridiculous things like that, a REAL MYLAR LINER IS AN OXYGEN BARRIER.
snip.
No professional packing house uses dry ice or DE for food storage. Contact all the big places- OFD, Walton, Honeyville, etc. NONE of them use dry ice and only one packer that I know of still uses an actual nitrogen flush.
Dry ice- dry ice was used in the long long ago before mylars and absorbers became commonly available. It's principal use is as a FUMIGANT- i.e, to kill bugs. Yes it will displace some of the oxygen at the time the bucket is sealed. However since the bucket BY ITSELF is not an oxygen barrier, it's effectiveness over the long term is dubious.
Dry ice can be hard to find, can raise eyebrows when purchased (for you all wanna be 'gray men' types) and has safety issues.
People that have never packed food before should not attempt to use it, IMO. Their are easier and more thorough ways.
The fact that a bucket alone is NOT a true oxygen barrier is clearly shown in this video-
YouTube - Long Term food storage results pt1
look at the oxidized rice. If the bucket alone WAS a true oxygen barrier the rice would not show signs of oxidation.
So since you cannot use dry ice with mylar, the reasons for using dry ice are not many.
And as to the bug issue- the simple way to defeat that is good planning. Don't buy the one 50 lb. bag of rice that's been sitting on the shelf for 5 years at Festus Fishing shop and expect it not to have bugs. Buy from a big store with a high turnover- like Sam's, Costco, etc. This isn't always possible for certain items, so with the others, buy during COLD WEATHER. I can guarantee you that any wheat purchased from a feedstore from about this time of year until November in this area WILL have bugs in it. Why? Because this area is high heat and high humidity, basically bug central!
So you get all your ducks in a row FIRST- have your buckets, mylars and absorbers on hand. Get your dry goods in from a high turnover place and then pack them ASAP. Don't let them sit around for six months or-depending on where you are in the country- you could have bugs develop.
So how do you pack-
YouTube - Long term food storage part 1
This is exactly how many manufacturers pack their Superpails. This isn't reinventing the wheel, this isn't stepping over a dollar to pick up a dime, this is common sense procedures that if done properly WILL keep your whole grains ready for your use 10-15 years or more into the future.
I don't talk much about what I've done, but it's worthwhile for me to say that I ran a commercial cannery in 1998 and 1999 where we packed well in excess of half million lbs. of long term storage food in Superpails and #10 cans in that time period. So I'm not someone with "10 buckets under my belt" who doesn't know what they are talking about. I have stored food since 1986.
The biggest problem I see right now is people trying to reinvent the wheel. Figure out how the real deal professional packers do it, then copy their techniques. It doesn't really get much more simple than that!
Good luck!
Lowdown3