Skip to navigation Skip to content

 

Oxygen Absorbers and Long-Term Food Storage - An Introduction


What are Oxygen Absorbers and Why Are They Used in Long-Term Food Storage?

oxygen absorbers

Oxygen Absorbers are used to remove oxygen from within a sealed environment, creating a nitrogen environment for long-term food storage. They protect dry foods from insect damage and help preserve product quality. They are used when dry foods are packaged in sealed containers. When used with proper packaging and sealing, the oxygen in the packaging is greatly reduced. Our absorbers bring the oxygen level down reliably to .01% or less.



What Are The Benefits Of Using Them?

  • Extends shelf life
  • Prevents growth of aerobic pathogens and spoilage organisms, including molds
  • Eliminates the need for additives such as BHA, BHT, sulfur dioxide, sorbates, benzoates, etc.
  • Use with gas flushing/vacuum packaging to absorb virtually all oxygen and absorb any oxygen that may permeate the package



How Do Oxygen Absorbers Work?

Oxygen absorbers perform their action through a chemical reaction. They contain iron powder which reacts with the oxygen in the air causing the iron powder to rust. When all the iron powder has oxidized, the oxygen absorbers are "loaded" and the absorbing action stops. Remove the oxygen from an active absorber and the chemical reaction stops. Put them back in the air and the reaction starts again until the iron is gone.



What Are Oxygen Absorbers Made Of? Are They Dangerous to Come in Contact with Food?

Oxygen absorbers are small packets that contain an iron powder. The packets are made of a material that allows oxygen and moisture to enter but does not allow the iron powder to leak out. The Oxygen Absorbers are safe to place on top of the food. They will not harm the food they are in contact with as they come in a sealed pouch.



How Long Does it Take For the Oxygen Absorbers to Work?

Oxygen Absorbers become warm to the touch when they are working. They take about 4 hours to achieve their rated maximum absorption.



Do I Need Any Other Product To Remove Moisture?

Desiccants are used with food which has a high water content which can't be stored long-term very well anyway. Using desiccants is not required with dehydrated foods, at least those that we carry.



Can I Just Freeze My Food Instead To Keep It Good Long-Term?

Many customers ask if their food will last longer if placed in a freezer. Most items will last significantly longer under cooler temperatures. While dehydrated food is relatively stable under freezing conditions, still your best solution for long-term food storage is to go with an oxygen-free environment.



Is The Use Of Oxygen Absorbers Equivalent To Vacuum Packaging?

Oxygen absorbers remove oxygen more effectively than vacuum packaging. Air is about 20 percent oxygen and 80 percent nitrogen. Absorbers remove only the oxygen. The air left in the container is mostly nitrogen and will not affect the food or allow the growth of insects. Therefore, the final packaging may not have the appearance of being "vacuum-packed" because of the remaining nitrogen in the package. The only way to get a good vacuum seal inside the bag is to use a vacuum sealer.

Oxygen absorbers alone will not be able to accomplish this as they only remove oxygen, which is roughly 20% of the air inside the bag. However, the goal should be to remove the oxygen as the remaining contents of the air will not affect the long-term storage life of your food.



What Types of Food Products Can Be Stored Using Oxygen Absorbers?

Products should be low in moisture and oil content. If the moisture content is not low enough (about 10 percent or less), storing products in reduced oxygen packaging may result in botulism poisoning. All of our dehydrated products meet the 10 percent or less criteria. However, some products (for example, granola) contain nuts which because of their oil content has a shorter shelf life of up to 6 months to a year.

To learn more about the shelf-life of the various dried foods we carry, please refer to the Information Center under Storage Life of Dried Foods



What Types Of Containers Can Be Used With Oxygen Absorbers For Food Storage?

  • number 10, number 2.5 cans#10 and #2.5 Metal Cans with Seamed Lids
    Food products can be found on our website in both #10 cans (which measures 7 inches tall and is a little over 6 inches in diameter, which is roughly the same size as a large coffee can that you'd find in the store) or in #2.5 cans (about the size of a small baking soda can). As far as the difference in the #10 vs. a #2.5 cans, is that the #2.5 is roughly 1/4 the volume of the #10. Both of the cans come with a lid on the can. All of our food products that are stored in cans include Oxygen Absorbers so that are already prepared for long-term storage.
  • mylar bagsMylar Bags
    Mylar Bags are an integral component of any good food storage systems. Food grade metalized mylar bags are used for lining food storage pails. Mylar bags create an oxygen barrier to protect food during extended long term storage. If you want the best, use mylar bags which cut this air transfer down to almost nothing.
  • plastic food storage bucketFood-Grade Plastic Storage Containers
    You can purchase empty buckets to store your own food. The food storage pails and lids are made of high-density polyethylene (HDPE) and meet NMFC, FDA and UFC requirements. All of our food storage buckets have a sturdy wire bail with a plastic handgrip. Made with a tapered design, our plastic food storage buckets nest to save space, and they separate easily. Use of an air-tight lid with a gasket is necessary to create a sealed environment.
  • A SuperPail "SP" or Regular Bucket "RB"
    You will also see food products on our website offered in a "SP" or "RB". If it reads "SP" then it is a SuperPail food-grade bucket with the product vacuum-sealed inside a mylar bag with oxygen absorbers inside the bucket. If it reads "RB" it is a Regular Bucket food-grade bucket and is vacuum-sealed with oxygen absorbers with no mylar bag inside the bucket.
  • gamma seal lidsGamma Lids with Food Storage Containers
    The Gamma Seal lid transforms most 12" diameter plastic pails into leak proof, airtight storage containers that protect the contents from exposure to the environment. The Gamma Seal lid is not only re-sealable, but the heavy duty construction allows it to be reusable. The Gamma Seal Lids that we carry fit all of the buckets that we sell - from the 4.25-gallon to the 6-gallon size buckets.
  • mason jarsGlass canning jars with metal lids that have gaskets (eg. Mason Jars)
    Mason jars provide a time-tested and proven way to store fresh fruits, vegetables and other items for long-term storage.


  • If I am Going to Use a Food-Grade Bucket, Do I Also Have to Use a Mylar Bag Inside?

    It is not necessary to use a Mylar Bag within a food grade bucket, but the use of one provides an additional level of protection. That way you are ensuring that your food storage investment is kept in the best possible shape and stays that way until you need it. The plastic buckets are slightly porous and will allow some air transfer - the use of Mylar Bags will cut the O2 transfer down to almost nothing.



    Can I Use Just Any Storage Bucket, For Example One Purchased At Home Depot?

    We get this question a lot. The answer is that the Home Depot type buckets could be safe, but it is not recommended for food storage. It is best to use food-safe approved buckets. The buckets that we sell are food grade and are 90 mils thick. They are thicker and are made of a food-safe approved plastic.

    So, how do you find buckets that are safe for you to use for the foods you want to pack yourself? If you are going to buy them new, ask the company who is selling them. If you get used buckets, only use buckets you know have already been used to store food and haven't been used for anything else. You can find these at bakeries, ice cream manufacturers and parlors, large restaurants or kitchens, or food processing plants.

    Please keep in mind if you are searching for food-grade storage buckets that most plastic containers (usually on the bottom) will have a number inside a small triangle. All the buckets we have seen have a #2 on them. This number doesn't mean that it is food grade, but rather it tells what kind of plastic the bucket is made of. The #2 means it is made from HDPE (high-density polyethylene) plastic. Most of these buckets are food grade but there are times when they are not.

    Sometimes the bucket has a dye added to the plastic that is not food grade. This alone will prevent the FDA from approving it as food grade. And sometimes the bucket manufacturer uses recycled HDPE. These buckets also are not food grade. And lastly, when something is put in the bucket that is a non-food type product such as paint, chemicals, and such things; this also makes them so they are no longer food grade. HDPE plastic is slightly porous and will absorb these chemicals which will gradually leach back into any food you place in the bucket later.



    What Is The Proper Way To Use Oxygen Absorbers?

    The oxygen absorbers should be placed inside the container on top of the food. They will not harm the food they are in contact with as they come in their own sealed pouch. We've created a table that you can use to get an idea of how many oxygen absorbers you might need for different size storage containers

    Here is an example of the steps you should follow when packaging your food for long-term storage using Oxygen Absorbers:

    • Cut open the top of the bag of Oxygen Absorbers (they come in either a 100-count or 50-count sealed bag). Do not open or cut into the individual Oxygen Absorber packets.
    • Take out only the amount that you are going to need. The Oxygen Absorbers you are about to use should be laid out side by side so they are not touching each other. The reason for this is because as they work they generate heat and the hotter they are the faster they will absorb oxygen. The goal is for them not to absorb any more oxygen than is necessary before they are sealed into the storage container where you will then want them to do their thing. Try not to leave them out for any longer than 20 minutes. The best method would be to take them out right before using them - to achieve the maximum absorption out of them.
    • Once the original package of Oxygen Absorbers is opened, you should immediately move the packets that you are not going to use into another air tight package. We recommend using a small, glass canning jar that as a metal lid with a gasket. A one-pint jar (500 ml) will hold 25 absorbers. Note: Do not store absorbers in grocery store type zip-lock bags.
    • Place the desired amount of Oxygen Absorbers on top of the food and seal the container. Keep in mind that the goal is to remove the Oxygen from the air inside the storage container. Air is approximately 20% Oxygen and 80% Nitrogen, so you may not get that "vacuum-sealed" appearance after the process has completed (since there will still be the approximately 80% Nitrogen left within the storage container.)

    More detailed instructions can be found here