Oxygen Absorbers: WHY?
One of the primary enemies of long-term food storage is oxygen. Enzymes in food interact with oxygen, causing the quality of the food to deteriorate. Insects, bacteria, mold, and fungus all depend upon oxygen. Without oxygen, they cannot survive. Therefore, it’s essential to get as much oxygen out of a food storage container as possible.
There are a variety of methods of doing this. Begin by packing food tightly, leaving no room for air. Some hard-core preppers use bottled nitrogen, or the carbon dioxide generated by dry ice to displace oxygen in the container. But most preppers use oxygen absorbers.
Oxygen absorbers are small packets that contain iron filings, salt, and clay. The clay provides moisture. When moisture, salt, and iron are exposed to oxygen, it causes the iron to oxidize, forming rust. The process of rusting uses up available oxygen, and gives off nitrogen. Food packed in nitrogen lasts much longer than food packed in oxygen.
Oxygen absorbers come in different sizes for different prices, ranging from tiny 20 cc packets suitable for a single serving of jerky, to 1500 cc packets used inside five-gallon buckets. Usually they are sold in bulk, such as a 50-pack inside a single vacuum-sealed bag. However, they become activated as soon as they come into contact with oxygen, so as soon as the package is opened, they begin to expend themselves absorbing oxygen in the room. Therefore, either all 50 packets need to be used at once- and quickly- inside 50 different containers, or the package containing the leftover unused packets must be re-sealed immediately. Some people re-seal them using a seal-a-meal device; others pack them tightly inside jars.
DO NOT use oxygen absorbers with sugar. It will cause the sugar to harden into a block. Oxygen absorbers should be used only in dry foodstuffs and not with any product that will get them wet such as honey, ketchup, syrup etc.
As long as you’re going through the trouble and expense of squirreling food away, you might as well protect your investment. Oxygen absorbers will cut down on the number of unpleasant surprises on the day after doomsday.
Don’t confuse oxygen absorbers with desiccants. Many products come with little packets of silica gel labeled “DO NOT EAT”. You'll find them inside bottles of medications, in packages of jerky and pepperoni, even inside shoe boxes and new purses. Silica gel absorbs and releases moisture, keeping the humidity inside a package steady and constant. However, silica does not affect the oxygen level inside a package. A silica packet placed inside a container that also has an oxygen absorber inside it would do more harm than good. The oxygen absorber requires moisture found in the clay in order to work; the silica absorbs that moisture, halting the process.
One alternative to oxygen absorbers is to use disposable hand warmers instead. With names like Hot Hands or Toasty Toes, these slender pocket-size chemical warmers operate on the identical principle as oxygen absorbers. Each pouch contains iron powder, salt, water, an absorbent material such as vermiculite, and activated carbon. When the pouch is removed from its airtight outer Mylar sheath, oxygen drifts across the pouch’s permeable covering. With salt and water present, the oxygen reacts with the iron powder located inside to form iron oxide (rust) and release heat. The vermiculite helps to retain the moisture in order to promote the chemical reaction, while the carbon distributes the heat evenly. Temperatures usually reach about 135 F. Drop an activated packet into a five-gallon bucket of food, and you’ve got an excellent oxygen absorber. These hand warmers have the advantage of being packaged singly, so they can be used as needed without fussing with re-sealing the remainder.