What Is An Oxygen Absorber: Long Term Food Storage


If you are preparing to store survival or emergency food in long-term storage, you need to know all about the simple little packets of iron powder that remove oxygen from sealed food containers. There isn’t a simpler, more effective way to prevent oxidation of food and kill bugs, but what is an Oxygen absorber?

An Oxygen absorber is a small non-toxic packet filled with iron powder and salt. They are placed in sealed food containers to remove oxygen to prevent food deterioration from oxidation, aerobic bacteria, fungi, mold, mildew, and bug infestation.

10 Reasons To Use Oxygen Absorbers

  1. Absorbers extend the shelf-life of dried foods by decades, providing a shelf -life of 30 years or more
  2. Prevent deterioration of food by oxidation
  3. Kill insects at all stages: eggs, pupae, and adult, within 2 weeks. Freezing before repacking not necessary.
  4. Slow or stop the growth of aerobic molds, mildew, and bacteria
  5. Improve the shelf-life of polyunsaturated fats and oils (take this with a grain of salt, high-fat foods like brown rice will not last significantly longer even using absorbers.
  6. Delay discoloration of food
  7. Eliminate the need for preservatives like sulfur dioxide and sorbates
  8. Foods aren’t crushed as with vacuum packing
  9. Prevent oxidation of vitamins like A, C, and E
  10. Simple and easy to use

How Do Oxygen Absorbers Remove Oxygen?

Oxygen absorbers remove oxygen in a sealed food package when moisture in the food and air chemically reacts with the iron powder in the oxygen absorber, causing it to rust. When all of the iron in an absorber rusts, it will no longer remove oxygen from the package.

The size of your food storage container and the amount of space between each piece of food will determine how much CC of oxygen absorption you will need. For example, you need more cc absorption for dried beans than you do for white rice because there is more space between the beans than there is between rice grains.

When you are using Oxygen Absorbers in storage, set everything up before opening the absorber package to minimize the amount of time exposed to air. They will start working once exposed to air. Each absorber has a limited capacity, Indicated by the size in cc or cubic centimeters.

You can tell an absorber is working because it heats up. Make sure to seal absorbers up as quickly as possible, both in the food package and the absorbers you don’t use.

Storage Tip: Use a small Mylar bag or a ball jar to seal up your leftover absorbers.

How Many Oxygen Absorbers Do I Need

Oxygen Absorbers remove food through chemical reactions. To simplify it, oxygen absorbers eat oxygen, but they can only eat so much based on their size or cc. If you have a larger container with more oxygen, you need a big hefty absorber or many small ones to eat the oxygen present.

The exact cc of oxygen absorber you need will vary depending on the size of the container and the amount of air space which depends on how much of the container you leave empty and the size or density of the foods stored.

You can’t use too many oxygen absorbers, so always add more if you are in doubt. When packaging dry foods, I usually go over suggested cc’s to be safe.

Take a look at the suggested absorption requirements, by cc, in the chart below.

Chart 1 Recommended Oxygen Absorbers

Container TypeWheat/Flour/Grains/Rice
More Dense/Less Air
Pasta/Beans
Less Dense/More Air
Food Storage Pails#Of Each Size Absorber# Of Each Size Absorber
6-gallon100cc: 20
500cc: 4
1000cc: 2
2000cc: 1
100cc: 25-30
500cc: 5-6
1000cc: 3
2000cc: 2
5-gallon100cc: 20
500cc: 4
1000cc: 2
2000cc: 1
100cc: 25-30
500cc: 5-6
1000cc: 3
2000cc: 2
Mylar Bags
20in. x 30in. (4.25, 5, and 6 gallons)
*Used to line food-grade bucket(s)
100cc: 20
500cc: 4
1000cc: 2
2000cc: 1
100cc: 25-30
500cc: 5-6
1000cc: 3
2000cc: 2
18in. x 28in. (4.25, 5, and 6 gallons)
*Used to line food-grade bucket(s)
100cc: 20
500cc: 4
1000cc: 2
2000cc: 1
100cc: 25-30
500cc: 5-6
1000cc: 3
2000cc: 2
14in. x 20in. (2.0 gallons) 100cc: 10
500cc: 2
1000cc: 1
2000cc: 1
100cc: 15-20
500cc: 3-4
1000cc: 2
2000cc: 1
14in. x 18in. x 6in. (2.0 gallons)100cc: 10
500cc: 2
1000cc: 1
2000cc: 1
100cc: 15-20
500cc: 3-4
1000cc: 2
2000cc: 1
12in. x 18in. (1.5 gallons) 100cc: 5-8
500cc: 1-2
1000cc: 1
2000cc: 1
100cc: 10-12
500cc: 2-3
1000cc: 1-2
2000cc: 1
12in. x 16in. x 6in. (1.5 gallons)100cc: 5-8
500cc: 1-2
1000cc: 1
2000cc: 1
100cc: 10-12
500cc: 2-3
1000cc: 1-2
2000cc: 1
10in. x 14in. (1 gallon)100cc: 3-4
500cc: 1
1000cc: 1
2000cc: 1
100cc: 4
500cc: 1
1000cc: 1
2000cc: 1
8in. x 12in. (1/2 gallon)100cc: 1-2
500cc: 1
1000cc: 1
2000cc: 1
100cc: 2-4
500cc: 1
1000cc: 1
2000cc: 1
6in. x 10in. (1/4 gallon)100cc: 1
500cc: 1
1000cc: 1
2000cc: 1
100cc: 1-2
500cc: 1
1000cc: 1
2000cc: 
6in. x 8in. x 2in. (1/4 gallon)100cc: 1
500cc: 1
1000cc: 1
2000cc: 1
100cc: 1-2
500cc: 1
1000cc: 1
2000cc: 1
Ball or Canning Jars
1 Quart Jar100cc200cc
1 Gallon Jar400cc600cc
*Note, these are average amounts at sea level. You may need more or less depending on your individual conditions and the remaining residual volume of air. There is no danger in adding too many Oxygen absorbers as this does not adversely affect the food.

Oxygen represents 21% of the total volume of air, and the number in cc’s above represents the amount of oxygen that would be absorbed.

Conversions: 1cc = 1ml. 1000ml = 1 Liter. 3.78 Liters = 1 gallon. Information compliments of USA Emergency Supply

What Kind of Foods Are Stored With Oxygen Absorbers

Once you use oxygen absorbers to store food, you’ll recognize how awesome they are. Inexpensive, easy to use, and effective. Besides purchasing professionally packaged food, there isn’t a better, more well-rounded method of preserving food for long-term storage. The only issue with absorbers is they are used primarily to store dry foods.

When using Oxygen absorbers for food storage, only store low moisture, low oil foods. You’ll see many talks about using oxygen absorbers in high-fat foods, dehydrated fruits and vegetables, trail mix, and beef jerky. Keep in mind that these foods must be less than 10% in moisture.

High moisture, low oxygen storage environment is the perfect environment for anaerobic bacteria like botulism food poisoning to form. It’s rare, but it’s lethal.

10 Foods To Store With Oxygen Absorbers

  1. Dried White Rice
  2. Dried Pasta and Macaroni
  3. Dehydrated fruit/veggies (below 10% moisture) They must snap. If they are still flexible, moisture is too high.
  4. Powdered Milk
  5. Dried Corn
  6. Dried hard and soft grains
  7. Wheat (to kill bugs and avoid adding water by freezing)
  8. Beans and Legumes
  9. Potato Flakes
  10. Oatmeal

Foods You Don’t Store With Oxygen-Absorbers

.Oxygen-free storage is for dry staple foods. Any food higher in moisture or high in fat is not an ideal candidate. It’s either not effective, dangerous, or to store high moisture foods in an oxygen-free environment.

Don’t use oxygen absorbers or oxygen-free storage with foods that are more than 10% moisture content. There is a higher risk of anaerobic bacteria such as botulism. Botulism is a rare but deadly type of food poisoning.

Foods You Should Not Store Oxygen-free

  • Food High In Moisture (10% or higher)
  • High-fat content foods
  • Pre-milled grains
  • Pearled Barley
  • Nuts
  • Meat Jerky
  • Granola or trail mix
  • Dried Eggs (commercially freeze-dried are different)
  • Brown Sugar
  • Dried Fruits (if not dried enough to snap when bent)
  • Dried Vegetables (if not dried enough to snap when bent)
  • Powdered foods like sugar, salt, drink mixes will turn into a rock
  • Baking Soda (may explode)
  • Baking Powder (may explode)

Food Shelf Life With and Without Oxygen-absorbers

If you are interested in collecting enough food for each person in your household to survive on foods you have stored then, Oxygen-absorbers are your friend. You can increase the shelf-life of foods exponentially by repackaging them into oxygen-free containers.

Chart 2: Food Storage Life With and Without Oxygen Absorbers

Food TypeShelf-life Without Oxygen absorbersShelf-life with Oxygen Absorbers
Wheat6 Months30 years
White Rice5 Years30 years
Rolled Oats6 to 9 months30 years
Bleached Flour6 months10 to 15 years
Dried Pasta/Macaroni2 years30 Years
Dried Bean & Legumes1 to 2 years30 years
Potato Flakes12 to 18 months30 years
Non-fat Powdered Milk18 months20 to 30 Years
Dried Dent/Field Corn6 months30 years
To obtain the maximum shelf-life foods must be sealed in a container that provides and oxygen barrier with the proper CC oxygen absorption and stored in a cool dry location.

5 Types of Containers To Use With Oxygen Absorbers

Containers used with oxygen absorbers should provide a true oxygen barrier, such as Mylar bags or #10 cans. You can also choose to slow the transfer of oxygen by using plastic, which is not a true-oxygen barrier. Two containers that fit this description are food-grade buckets and PETE Bottles.

5 Containers Used With Oxygen Barriers

  1. #10 Cans-True Oxygen Barrier
  2. Mylar Bags-True Oxygen Barrier Mylar Bags For Food Storage: Beginners Guide
  3. PET Plastic Bottles (sterilized, reused soda bottles)-slow oxidation but overtime will transfer oxygen into the container
  4. Glass Jars (Canning or Ball Jars)- True oxygen barrier but don’t protect food from light oxidation
  5. Food Buckets or Pails-Slows Oxidation but over time will transfer oxygen into the container. Excellent when lined with sealed Mylar bags and an Oxygen Absorber.

A package that provides a true oxygen barrier will keep additional oxygen out of the food container after the Oxygen absorber removes oxygen inside.

The most popular oxygen containers used are Mylar bags and #10 cans because they provide an excellent oxygen barrier. Plastic buckets are commonly used, but they are not a true oxygen barrier. It’s better to use plastic food-grade pails and buckets lined with Mylar. You kill two birds with one stone, the Mylar keeps oxygen out, and the bucket protects the Mylar.

Do I Need To Use Oxygen Absorbers For Long-term Storage?

You need oxygen-absorbers when repackaging dry staples for maximum shelf-life. By removing oxygen from storage containers, the shelf life of dried staples like white rice, wheat berries, and dried beans is increased by decades.

Many staples have a pretty long shelf from 1 to 5 years, so if you plan on rotating through your panty, Oxygen-free storage isn’t necessary. For long-term survival, they are superior to any other DIY method of killing all bug life stages and increasing shelf life by minimizing damage to food via oxidation and bacterial growth.

Will Oxygen Absorbers Kill Bugs?

There are other methods of killing bugs in food than Oxygen absorbers but they are all more complicated than dropping absorbers in a Mylar bag.

One alternate method is using dry ice to add carbon dioxide to the container, but it’s dangerous and a hassle to work with.

Non-professionals shouldn’t even consider fumigating food and freezing actually adds moisture to food, the bain of dry grain storage and the professionals disagree on how to freeze food properly to kill bugs.

For ease of use and effectiveness, Oxygen absorbers and Mylar bags are the best method of killing bugs.

When oxygen absorbers remove oxygen from a sealed food package, they kill bug eggs, pupae, and adult bugs within 2 weeks.

When repackaging dried foods for decades of storage, taking care of the bug issue is important. Most foods come with bug eggs so microscopic you can’t see them. If you don’t repackage food in an oxygen-free container, it will degrade from oxidation, and any bug eggs present will hatch so that you might come back to a squirming mess.

Following is a Ready Squirrel video covering “why you shouldn’t freeze dried foods for repackaging.”

How to store food in Mylar bag, food-grade bucket with Oxygen-absorbers

Sources

Oxygen Absorbers, Carolyn Washburn, FCS Agent, Associate Professor, Utah State University: Cooperative Extension PDF

USA Emergency Supply Link

Related Articles

Food Grade Plastic For Food Storage, Scott Foster, Readysquirrel.com

Oxygen Absorbers and Food Storage, Scott Foster, Readysquirrel.com

Mylar Bags: The Secret Weapon of Food Storage, Scott Foster, Readysquirrel.com

Top 6 D.I.Y. Containers For Long-term Food Storage, Scott Foster, Readysquirrel.com

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