The Difference Between Oxygen Absorbers and Silica Gel

I was telling a friend who is new to preparedness about packing bulk foods for long terms storage, when she asked me if oxygen absorbers are the same thing as the little  packets you find in new purses and shoe boxes that say “Do not eat.”   This reminded me that I was confused about this at one time so I thought I’d do a quick post about it.

oxygen absorber

Oxygen Absorbers

Oxygen Absorbers

Oxygen absorbers are tiny sachets that contain iron filings, salt and clay.  The clay provides moisture, and works with the salt to activate the iron filings.  The process starts as soon as the oxygen absorber packets is exposed to oxygen.  What happens is the iron filings begin to oxidize, forming rust which then releases nitrogen.  Nitrogen helps the food keep fresher longer.  The lack of oxygen in the stored food will keep weevils and other insects from living in there.

Most oxygen absorber packs come with a little pink pill that turns blue if the oxygen absorber is no longer effective.  A few other notes about oxygen absorbers:

  • Sugar and salt for long term storage do not need oxygen absorbers as they will turn rock hard.
  • Once you open a pack of oxygen absorbers, take what you need and keep the rest in an airtight jar, not a plastic bag.  Keep their exposure to air as little as possible.  Otherwise they will all get activated and useless by the time you need them.
  • To be effective, you need to use the right number of oxygen absorbers for the food you are packaging.  This site has a handy chart on how much oxygen absorbers to use. (We have no connection to this site, just found the chart helpful.)
  • Oxygen absorbers cannot be reused.

Silica gel

Silica gel

Silica Gel

Silica gel is made of silicon dioxide, essentially, porous sand.  It is used to reduce condensation and allows the stored item to stay dry even during humid, damp conditions. You find them in bottles or packages when you buy vitamins, purses, shoes, even computer equipment.  Because silica gel inhibits moisture, it therefore prevents mold to grow.

If you are packing a 5 gallon bucket with silica gel to keep moisture at bay, you will need a 10 gram silica gel packet.   Some items that can be packed with silica gel include:

  • photos
  • camera equipment
  • prescription and non prescription medicines
  • ammunition cans and gun cases
  • seed packets
  • tool boxes
  • luggage
  • important documents

Silica gel packets can be reused.

I haven’t tried it, but silica gel packets can be reactivated – see these instructions from eHow.

Can oxygen absorbers and silica gel be used together?

The answer is NO, they should not be used together.  The reason is, oxygen absorbers require moisture in order to work.  If the silica gel absorbs the moisture, it will halt the activation process of the oxygen absorber, rendering it useless.


© Apartment Prepper 2014

Preppers Pocket Guide

About the Author:  Bernie Carr is the author of The Prepper’s Pocket Guide:  101 Easy Things You Can Do to Ready Your Home for a Disaster. Her latest e-book, How to Prepare for Most Emergencies on a $50 a Month Budget, provides tips on low-cost prepping.

Her blog, Apartment Prepper,  is about family preparedness while living in a city apartment.

This information has been made available by Ready Nutrition

Originally published March 11th, 2014
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One Response to The Difference Between Oxygen Absorbers and Silica Gel

  1. DaveH says:

    Oxygen absorbers do not produce Nitrogen.
    One atom of Iron takes up one atom of the ambient Oxygen and forms one molecule of Iron Oxide ( FeO )

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