Storing Flour in Mylar w/O2 absorber question

[momof4survivor]

Is it to be expected that substances such as flour and powdered milk will not become as "compact" as other items stored in buckets w/O2 absorber and mylar? I have a 25 lb. bag of flour w/ 2 1000cc O2 absorbers and am not seeing the bag as sucked in as with beans and wheat. Just wondering.

[cranky1950]

The head space at the top of the bag should tuck in, but no the lower portion of the bag will not give because there is little space between the grains of flour thus no give. Flour is pretty much compacted and forms a solid mass when you tamp the bag as you fill it. Beans and bigger things will move around as the O2 is removed and the bag is pulled tight.

[momof4survivor]

The top 4 inches or so of the bag are laying together, but if I give it a gentle tug, it just doesn't feel so tight, like the sides begin to separate. I originallly had 1, 1000cc O2 absorber and was concerned that the head space was not taken up enough so I opened it back up and put in 2, 1,000cc O2 absorbers. It is a little better than it was. I'm guessing this is the best it will get.

[cranky1950]

Since essentially the head space contains all of the O2 there is not much volume of O2 in the bag, so there will be much less of a vacuum formed than say beans which have a relatively big volume of atmosphere in the mass of beans so a greater volume is removed from the bag.

[goose3]

When you have fine particles they pack together much more effectively, which does two things in your scenario: First, there's less air amongst the particles (imagine if you'd packed marbles instead), and second, it takes time for the oxygen that *is* amongst the particles to migrate to the O2 absorber.

I'd wait a day or two longer and see if things become tighter. If you're still not sure, the question is whether the seal is actually intact.

If I'm unsure, I'll grab some of the slack, and in pulling both sides away from the middle, see if I can get air to go back into the package. It may or may not be obvious, esp. if there's a pinhole that only admits air slowly. You can also try taking a couple of spring clothespins and attach them to elastic (rubber bands or what have you), and use them to try to pull the mylar in such a way that a leak would over time fill up the space [I hope that's clear].

Another thing I do when sealing is that I lay the back of my hand on the mylar where the O2 absorber should be, and see if it's warm; that's a sign it's working. Then the only question is whether the seal holds.

BTW, it's harder w/ flour, if you're packing it in loose form, to be sure you haven't fouled the seal with flour dust. I make sure I wipe off the inside of the mylar where I'm going to seal it, so as to ensure I don't have that problem. It's especially an issue for me w/ powdered milk, which just dusts up into everything.

Finally, I've got 50# of flour stored right now (at $1.19 per 5# at Aldi, how can I not?). The way I'm storing it is in 5-gallon buckets, with the 5# bags intact, inside mylar. I toss in a couple of O2 absorbers, squeeze out what air I can, and then seal it up. It doesn't draw tight--there's still way too much air between the bags of flour--but it does pull down some, so I know my seal works and the O2 absorbers work as well. If I recall the pattern correctly, I lay two flour bags on their sides in the bottom, then three of them upright on top of the two, and they barely fit.

[momof4survivor]

Thank you that's very clear. I'll try it your way next time.

[MikeK]

It takes an O2 absorber a while to absorb all the O2 in an environment like that where the air can't migrate around as easily as it could in something like beans. Give it a few more days before you worry too much about it. Different foods react differently when stored in mylar though. Like the guys said, there isn't as much air in the bag, so there isn't as much O2 to be absorbed. As long as your seal is good, I wouldn't sweat it much.