Do the Math

• The number of oxygen absorbers you need depends on how densely packed your food is; how much space your food takes up in the container; and how much food you have overall. To determine the packet size you need, convert the volume of food to cubic centimeters, where 1 gram is equal to 1 cubic centimeter. Subtract the volume of food from the volume of the storage container. Multiply this number by 0.21, as air is 21 percent oxygen -- this will give you the oxygen absorber size in cubic centimeters. Oxygen absorbers come in 50, 100, 300, 500, 1,000 and 1,500 cubic centimeter sizes. Use a slightly larger packet if you cannot determine your exact needs.

Storage and Use

• Foods commonly stored with oxygen absorbers include flour; salt; sugar; fine powders, such as baking soda or pancake mix; dried beans; and rice. Purchase oxygen absorbers at bulk foods stores, grocery stores or online sellers. Oxygen absorbers start absorbing oxygen as soon as they are exposed to air, so do not open a package of them until you are ready to put one in a food storage container. Close the container immediately after adding a packet. Store unused oxygen absorber packets in a sealed plastic bag with all of the air expelled from it. Use a vacuum sealer if necessary.