Letter: Advice on Oxygen and Moisture Absorbing Packets

Reader C.A. wrote to ask:

I was wondering if you guys had an answer to this or could direct me to the answer: Those oxygen absorber packs that you get inside of food like beef jerky and medication / pill bottles. Can those be re-used for food storage, etc.?

Also, who would you recommend as suppliers for these?


JWR Replies:

There are two quite different types of packets. They usually have identifying markings. The two main types are:

1.) Most of the pill bottles and many electronics come packaged with a silica gel (moisture absorbing) packet and those CAN be gathered up and then re-dried in batches on a cookie sheet in a low oven (175 F) for 8 hours, and re-used. Once they are re-dried you should immediately seal them in Zip-Loc bags, or they will begin to absorb the ambient room moisture, if left out.

2.) The oxygen O2 absorbers found in some food packages use an iron oxide chemical reaction process that starts once they are exposed to oxygen. Those CANNOT be re-used. So just discard those.

O2 Absorbers are available in sealed bags from Readymade Resources. (One of our advertisers)

Silica gel is available in bulk, very inexpensively:  Simply look for unscented Fresh Step brand cat liter box CRYSTALS. Just pour them into socks with a tight weave and either sew them or tie them closed with a rubber band.

I hope this helps. – JWR


  1. Someone also pointed out those hand and foot warmer packs (they heat up when exposed to air) are basically the same chemistry as the oxygen absorbers and will have the same effect. I don’t think there would be a “food grade” problem if handled right, and I think they are cheaper especially for large containers.

  2. I have been buying my O2 absorbers from https://www.sorbentsystems.com since prior to Y2K. (No commercial connection; I’m just a customer.)

    I figure it is better to over do it, so I use a 200 ml for a #10 can or a gallon glass jar and a 1500 ml absorber for a 5-gallon pail. If I’m doing something with lots of voids, like macaroni, then I double up.

    I have never used their moisture absorbing packets, but they sell those, too. I have purchased their heavy duty Mylar bags and they are nice and thick.

  3. I made some years ago using the same silca kitty litter wrapped in coffee filters. I have also revitalized silca thats been exposed to moisture by putting it on a cookie sheet on very very low heat in the oven for an hour. Pretty sure i read that here on the blog.

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