The Ultimate Guide to Oxygen Absorbers

In a true emergency, having a substantial stockpile of food is critical for survival. Without food, it’s unlikely that we can survive for more than a few weeks, even in the best of circumstances. So, it’s essential that we have an adequate supply of food in our emergency stores for when SHTF.

Unfortunately, simply having a lot of food in storage is not enough. Indeed, one of the most important things about stockpiling food is storing it properly. If you don’t, all that food that you have in storage can spoil and make you sick when you need it most.

Thankfully, there is a way to extend the shelf life of your food: oxygen absorbers. But, proper use of oxygen absorbers is important if you want to be ready for any eventuality, and a thorough understanding of how they work is critical.

So, to get you started, I’ve put together the ultimate guide to oxygen absorbers, complete with guidance on how to use them properly in your emergency stockpile. Let’s get started.

What Is An Oxygen Absorber?

Have you ever opened up a box of food or a jar of gummy vitamins and found that they had tiny little packets inside of them?

As a kid, your parents probably immediately took them away and threw them out so you wouldn’t accidentally eat them, but what was in those mysterious-looking packets?

It turns out that those packets are called oxygen absorbers. They are packed into thousands of different commercial food and medical products to help keep them fresh and in good condition while in storage.

Oxygen absorbers help extend the shelf life of many kinds of food, including:

  • Nuts and snacks
  • Spices
  • Flour
  • Cookies
  • Candy
  • Dried fruits

Oxygen absorbers are also used to help increase the shelf life of medications and medical diagnostic kits. You may also find them used in electronics and for the preservation of artwork.

When oxygen absorbers are packaged into food, it’s known as “active packaging.” This means that the container the food is in is actively helping to preserve it and extend its shelf life. Thus, oxygen absorbers are becoming more and more common in long-shelf-life foods.

What Are Oxygen Absorbers Made Of?

Also known as oxygen scavengers, most oxygen absorbers are generally made of small quantities of iron powder that’s mixed with salt. However, some oxygen absorber packets will contain activated carbon instead of iron.

In commercially-made oxygen absorbers, though, what’s in the packet is as important as the packet itself. Most modern oxygen absorbers come in a porous sachet, which allows the packet to remove oxygen from the environment.

However, in some food products, especially those high in fat, these paper sachets are likely to disintegrate, which can be dangerous for human health. So, some oxygen absorbers come in plastic packaging for lasting durability.

How Do Oxygen Absorbers Work?

The idea that a small packet of iron and salt can extend the shelf life of food can be a bit confusing, to say the least. However, the way that oxygen absorbers work is quite cool.

Basically, when you place an oxygen absorber in a container of food, it works to remove the oxygen from that micro-environment. As the oxygen and moisture touch the iron inside the oxygen absorber sachet, the iron oxidizes (a.k.a. rusts) to form iron oxide.

Any salt that’s added to the oxygen absorber simply acts as a catalyst, speeding up the process and allowing the iron to be more effective in dry environments.

As the iron oxide forms, it pulls oxygen out of the micro-environment inside the food container and produces nitrogen.

In fact, oxygen absorbers can reduce the oxygen level inside a sealed container to below 0.01%. If you consider that our atmosphere contains about 20.95% oxygen, this is pretty darn impressive for a little packet of iron.

Ultimately, by removing oxygen from the food container and adding stable nitrogen, the oxygen absorber helps prevent food from spoiling, which extends the shelf life of the food. This makes oxygen absorbers great for use in food storage, especially from a prepper’s perspective.

What Are The Benefits Of Oxygen Absorbers?

It turns out that those tiny little packets inside food containers make a big difference in preserving your food. But what exactly do they do, you might ask? Here are some of the benefits of using oxygen absorbers in a variety of environments:

  • Retains the flavor of roasted coffee
  • Prevents mold and pathogen growth in cheese and some other dairy products
  • Keeps nuts and trail mixes fresh for longer
  • Extends the shelf life of spices and seasoned food
  • Reduces and delays the browning of fruits and veggies
  • Eliminates or reduces the need for other additives, like sorbates

However, it’s important to keep in mind that some foods like sugar and salt, shouldn’t be used with oxygen absorbers because it will cause them to turn rock hard.

Other foods, as we’ve explained, though, can greatly benefit from the use of an oxygen absorber.

What Are The Dangers Of Oxygen Absorbers?

While oxygen absorbers are fantastic little bits of technology, if used incorrectly, they can be dangerous. As we’ve mentioned, in particularly fatty foods, the paper sachets that contain oxygen absorbers can disintegrate.

So, if you’re going to use them with fatty foods, opt for oxygen absorbers with plastic sachets.

Additionally, if you use oxygen absorbers with particularly moist foods, you run the risk of botulism poisoning. The bacteria that causes botulism thrives in moist, low-oxygen environments.

Since botulism is a serious illness that can cause death, prevention is key. Any food that you store with oxygen absorbers should have a moisture content of 10% or less, like rolled oats and dry beans.

How Are Oxygen Absorbers and Silica Gel Different?

If you’ve ever opened up a box containing a new pair of shoes, you’ve probably noticed those small packets that say “Do Not Eat” on them.

These little packets are called silica gels and look quite similar to oxygen absorbers.

However, while silica gel and oxygen absorbers sure do look similar, they are by no means the same thing.

While it’s easy to mistake them for one another, it’s important that you understand the difference between oxygen absorbers and silica gel, especially when it comes to storing your food properly for the long term.

Here’s what you need to know about silica gel:

Silica gel is what’s known as a desiccant, which means it helps remove water from an environment. This makes them different from oxygen absorbers which remove oxygen from an environment.

Modern silica gel packets are filled with tiny balls of silicon dioxide (a.k.a. silica), which is really good at pulling water and moisture from an enclosed space.

You’ll often find silica gel used in products like shoes, purses, electronics, and vitamins because it allows them to be shipped and transported in high humidity conditions without damage.

So, for a prepper, silica gel packets are best used for items like:

  • Important documents
  • Ammunition cans
  • Toolboxes
  • Photos
  • Medications
  • Seeds in storage

If you want to use silica packets for food like jerky and dried fruit, which are quite moist despite being dried, be sure that you buy food-grade packets – not the stuff that you’d find in a box of shoes.

Plus, since silica gel is a choking hazard, you want to be sure that your kids and pets don’t accidentally eat it. So, be sure to remove those silica packets from your food containers before any kids have access to them.

Finally, it’s important to note that you cannot use oxygen absorbers and silica gel together. Since oxygen absorbers need some moisture to function properly, if you remove all of the moisture with silica gel, the oxygen absorbers won’t be able to do their job.

So, it’s best to use one or the other – not both at the same time.

How Do I Use Oxygen Absorbers To Store Food?

At this point, you should have a pretty good understanding of what oxygen absorbers are and what they’re used for. So, up next, we’ll talk about how you can actually use them to extend the shelf life of your food.

What Size Oxygen Absorber Do you Need?

Before you can start storing food with oxygen absorbers, though, you need to buy some. However, there are many different oxygen absorbers available today, so it can be tricky to find the right one for your needs.

Modern oxygen absorbers will come in sizes that range from 20cc to 2000cc. The size of the oxygen absorber refers to the amount of oxygen that they can take out of an environment.

Therefore, a 20cc packet can only remove 20cc of oxygen, while a 200cc packet can take away 200cc of oxygen.

If you do a quick google search, though, you’ll find that there are many different recommendations for the size of oxygen absorber that you need.

In general, you can expect to use one 300cc packet for every gallon of food that you’re looking to store.

However, some food items are denser than others. This means that in a 1-gallon container of flour, for example, you’ll have less air inside than in a 1-gallon container of beans.

So, if you’re looking to store less dense food items, you might want to bump up that guideline to about 400cc of oxygen absorber per gallon.

Keep in mind, though, that there’s really no such thing as adding too many oxygen absorbers. You’ll only really find that you have a problem if you don’t have enough oxygen absorbers for your food.

So, to play it safe, it’s generally best to overestimate your need for oxygen absorbers when you’re packing your food for long-term storage rather than underestimate.

Check out this handy table I made:

1 Quart1 Gallon5 Gallons
Dry Milk502001000
Split Peas1004002000
Dried Beans (depends on variety)150400 – 5002000 – 2500
Pasta (depends on shape)150400 – 5002000 – 2500

What Should I Store My Food In?

The process of choosing a container to store your food in is incredibly important. But, it’s also quite a complex subject, so we won’t go too in-depth on it here.

However, when it comes to using oxygen absorbers, there are some important things to keep in mind as you choose what to store your food in.

The thing with oxygen absorbers is that they will only work at their best if they are in a truly airtight container.

If a container is not airtight, like a Ziploc bag, your oxygen absorber will absorb as much oxygen as it can, but won’t create an oxygen-free environment since there is air constantly leaking into the container.

So, when storing food with oxygen absorbers, you have two solid options:

Food Grade Plastic Buckets

Food grade plastic buckets are quite a popular method for storing food because they allow you to store food in bulk. Plus, plastic buckets are more or less rodent-proof and are quite durable.

However, plastic buckets on their own do not create a perfectly airtight environment. So, if you do want to use oxygen absorbers, you’ll want to use them in conjunction with mylar bags.

Mylar bags, also known as foil pouches, are great at protecting your food from moisture and light, so they’re great as a second layer of defense for your food inside a plastic bucket.

It’s also a good idea to use gamma lids on your plastic buckets to make them more airtight.

mason jars

Mason Jars

Mason jars are a fan favorite, especially among people that like to make jams and other preservatives. These glass jars are somewhat affordable and are completely rodent proof.

But, they can break somewhat easily (they are glass!) so Mason jars need to be stored and handled properly. Plus, Mason jars do not protect your food from the light, which means you need to store them in a dark location.

However, Mason Jars are great for creating an oxygen-free environment for your food In addition to using them with oxygen absorbers, you can get a vacuum sealer for Mason jars that is perfect for prepping them for long-term food storage.

Steps For Storing Food With Oxygen Absorbers

So, once you have your food, your containers, and your oxygen absorbers ready, it’s time to start storing your food. Here’s what you want to do:

  1. Get Your Containers Ready. Before you start, it’s important that all of your containers are completely clean and dry. Have the container lids at the ready so you can immediately seal them when you’re done.
  2. Prepare Your Food. Fill your containers with the food you’d like to store. Try to fill your containers as much as possible to reduce the amount of air inside.
  3. Get A Container Ready For The Oxygen Absorbers. If you’ll have any leftover oxygen absorber packets, it’s important that you have an airtight container to store them in. As soon as you open a package of oxygen absorbers, they’ll start to do their thing. The best way to preserve oxygen absorbers is in a vacuum-sealed Mason jar.
  4. Open The Oxygen Absorber Package. As soon as you open the package of oxygen absorbers, take on out and place it in your first food container. Seal the rest in the mason jar for the moment.
  5. Seal And Label The Food Container. Once you have an oxygen absorber in your food container, seal it immediately. Label it with the contents and the date of storage so you can have that information for future reference. It’s helpful to have a friend for this step to make you more efficient.
  6. Repeat Steps 4 And 5. At this point, you can repeat steps 4 and 5 for all of your food containers, making sure to limit the amount of exposure your oxygen absorbers have to a non-airtight environment. Voila! You have successfully stored your food with oxygen absorbers.

What Do I Do With Leftover Oxygen Absorbers?

If you bought your oxygen absorbers in bulk, you may have some leftover packets after you finish storing your food. Since you spent good money on these oxygen absorbers, it’s important that you store them properly or they may go to waste.

Once taken out of their original packaging, oxygen absorbers will only last for about 30 minutes out in the open.

As soon as you’ve finished storing your food, it’s important that you place your oxygen absorbers in an air-tight container. A mason jar that’s vacuum-sealed and stored out of direct sunlight is ideal.

Keep in mind that many oxygen absorbers will come packed with a little pink pill. This pill is used to tell you if the oxygen absorbers are no longer good. If this pill has turned blue, your oxygen absorbers will not work.

So, if you find this pill in the oxygen absorbers’ original packaging, it’s a good idea to place it in their new airtight container. This will make it easier for you to see if your oxygen absorbers are still good to use when you open the container again.

Oxygen Absorber FAQs

Here are our answers to some of your most common questions about oxygen absorbers.

Can You Freeze Oxygen Absorbers?

Generally speaking, oxygen absorbers shouldn’t be used at low temperatures. At low temperatures, the rate of oxygen absorption will be so low that oxygen absorbers just aren’t effective.

So, while they won’t hurt your food, oxygen absorbers simply won’t do much for you at low temperatures.

Why Can An Open Package Of Oxygen Absorbers Feel Warm?

Once you open a new package of oxygen absorbers, you may notice that it feels quite warm. Thankfully, this is nothing to be alarmed about.

The heat is just a result of the oxidizing reaction within all of the oxygen absorbers. To prevent this, seal the unused packets up immediately after opening.

What Happens If You Eat An Oxygen Absorber?

Since oxygen absorbers are usually made with iron, anyone who eats one runs the risk of developing acute iron toxicity.

However, the dose in most oxygen absorbers isn’t enough to cause serious problems in most healthy adults. Children, on the other hand, could become very ill from eating them. Basically, just don’t eat oxygen absorbers, and make sure your kids don’t, either.

Oxygen Absorbers: Critical For Food Storage

If you’re serious about storing food for a long period of time, oxygen absorbers are a must-have. These small packets of iron and salt can greatly extend the shelf life of dry food.

However, it’s important that you understand the dangers of oxygen absorbers and how to use them properly so you can be ready for when SHTF.

32 thoughts on “The Ultimate Guide to Oxygen Absorbers”

  1. I’ve seen mention of coffee beans but nothing on ground coffee. Can this be stored in a mylar bag with an OA? Also can you keep the product in it’s original packaging or do you have to decant it into a mylar bag?

  2. Can you guide us on the ways to make safe home made food oxygen absorbers please?
    I am researching all the products that can be used and put in coffee filters for large amounts of food.
    I like many am on a budget as well as prefer to support my food mills or hardware stores over Amazon or Walmart.

    Thank You so much!
    This is an excellent resource I have saved.

  3. Quick version: Is there any way to tell if an oxyab did work? (short of waiting 10 yrs and opening it)

    I know I’m late finding this, but if you happen to see this…

    I’ve been prepping for longer than the cute label existed but I focused on freeze dried things. I’m now a lot older and diabetic. As long as I stay keto, I’m not diabetic, so I’m now wanting to get into storing my own keto foods.

    Trouble is, I’ve had a series of oxyabs that don’t seem to work. I’m wondering if what I think I know about them is wrong.

    If I put a 2000cc (not a typo) oxyab into a pint size mylar (just to test one from the batch), would it not draw up, wrinkle, have some visual indication that it’s working?

    I realize it’s not going to shrivel up like a vac seal, that there’s still gas inside, just not oxy, but is there no visible indication?? Even for such a vast size mismatch as that?

  4. Hey 🙂 I’ve been prepping for years but always went with Mountain House stuff. I’d like to get into doing some of my own stuff now that I’m on a special diet to reverse diabetes.

    I thought I had read that an oxyab would get noticeably warm when first unpackaged and that’s how you’d be able to know it was still viable. Now that I’m just getting into it and having my own experiences, I haven’t found one yet, from multiple packs/manufacturers, that got warm when I sacrificed one for testing.

    The ones I’m seeing now come with a little pink dot in the package that very quickly turns dark when exposed to air, but if the oxyab was already spent before that was packaged in, the pink dot won’t help much.

    I would rather avoid a nasty surprise down the road. Could you give me any info about how to tell if they’re viable, please?

  5. Hi Can I just use 100cc on items you should for 50cc and 75cc (quart jars)? Also for items listed as 150, just put 2 of 100cc (quart jars). I just don’t want to buy so many that I might not use. Can you use for cereal, drink mixes and cookies the 100cc in quart jars.? What do you recommend to use for potato chips, popcorn, salt and sugar? I’ve seen people use bay leaves.

    Thank you

  6. You list dried fruit in the bullet-point list of things absorbers are handy for, then later you state that there is botulism risk for anything over 10% humidity, and to only use with oats/beans types. Can you please clarify? I packaged a lot of money worth of organic dried fruit with o2 absorbers in food saver bags, and now am reading about botulism risk, but can’t seem to get clear info on this.. thanks!

  7. What is the status of your food if the bag does not “shrink” down using OAs? For instance, I did small bags (1#) of rice, and I have about 5 out of 20 bags that did not shrink, are they ok-I used a 400cc in each bag, the size of bag was about 1/2-1/3 of a gallon. They were cut tops of gallon bags from prepping other food that didn’t need to be a full gallon? Also, I did gallon (1kg) of potato flakes, and those bags did not shrink down. Thoughts?

  8. I used oxygen absorbers with sprouted brown rice flour, thinking it was a whole grain, but later saw that oxygen absorbers should not be used with milled grain. Although I cannot find the moisture content of sprouted brown rice flour, it looks like brown rice flour has a 12 % moisture content. Does this mean I need to throw out what was stored? I see that your chart includes using oxygen absorbers for flour. I did see a different link showing a type of wheat flour having a moisture content on 11.9 %. I don’t want to take any chance of illness, but also hate to needlessly throw out food if unnecessary. Thanks for your guidance.

  9. I did not reseal the OA. After sealing my buckets with beans and rice. Are my OA still good or is there a way to reactivate them

  10. Hi I’m in the UK, I have a limited sized garden wish I had a larger homestead but anyhow am trying to prep, am new to this stuff. I am planning to buy some 10 litre food grade buckets and use Mylar bags. If it is 400 cc per 1 gallon and 1 gallon = 4.55 Litres or round off to 5 Litres would that equal 10 x 400 cc oxygen absorbers? or should I just use higher value oxygen absorbers in the buckets and smaller value like 400 in the individual Mylar bags? Many thanks maths is not my strongest asset ?

    • If the packet contents are still loose and not a hard/solid cunck in the packet, they can still be used, but will only be 20% to 50% effective when reused!

      • Thank you for your information. My OAs are hard and I’ve been searching to see if they were still good. So much for using the small olive jar for storage!

  11. Great info and thanks! I am in process of developing a preppers remote storage tube. This is basically a 4 inch conduit pipe filled with food, or tools, or ammunition, or household needs, or medical needs. Or comic books if you want! These things must be done way in advance of need, so storage conditions are paramount! And you can bury one, ten, or one thousand.
    The idea is, you prepare these things, then go way out into non inhabited public areas or even on your own land or land of friends, and bury them in the ground. Long before you need them. Then you make a list locating these using a map and compass. Then if needed, the members of your clan will each know where this list is located so they can find them if you are removed from the clan.
    Basically, research still in process. Why I am here.
    I intend to do a video on this, so detail is important. Can you or anyone else reading this offer any advice?

  12. Im going to be packaging products in Mylar bags with absorbers and then storing in 5 gallon gamma sealed buckets also with absorbers. Do I need to replace absorber in the bucket every time it is opened?

  13. Two questions.

    I am storing dried beans for long term storage and went through all the necessary steps. Some of the bags created the super tight feel, where other bags were looser feeling. Do I need to go back and redo the looser bags or will they be okay? Its been about a month since I did them. Also, I did not heat or freeze the dried beans will this be an issue?
    Secondly, I am looking into dehydrating fruits and vegetables for long term storage. Should I use glass mason jars for them or will the mylar bags work? Also, the oxygen absorber packs, would I use them in the fruit or vegetable?

    I guess it was more than two questions, but any help would be great. Thank you!!

  14. I have gallon jars with the very wide mouth, no vacuum sealer will work. Can I sore beans, rice, peas, and just use an oxygen absorber.? !000cc?

  15. I am interested in using oxygen absorbers in mason jars for long term storage of flour, beans, pasta etc.
    Do the jars need to be sterilized or just clean & dry?
    If they need to be sterilized can I sterilize a week in advance and just store the jars & lids for later filling?
    Thank you for any help.

  16. Hi Gaby, this was a very informative post! I wonder if you could expand (or The Pack could pipe in) on what size absorbers to use for ‘X’ size containers or for particular foods.

    • Hey Grammyprepper,

      I just asked Gaby to provide a table and added it to the article. Thanks for your feedback!


    • I call Bull S**t on your explanation on how an Oxygen absorber works. Iron oxidizing doesn’t release Nitrogen. if salt is the catalyst, it doesn’t factor into the chemical equation. So, where does the Nitrogen come from exactly? As air is roughly 70% Nitrogen, when you take the Oxygen (21%) out you get a concentration if Nitrogen of around 88%. are you saying the nitrogen content increases above 88%? If so, where does it come from?


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