Survival Basics: Using Oxygen Absorbers for Food Storage

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When I first started getting serious about food storage, I found myself facing an entirely new vocabulary of food storage terms. It should come as no surprise that one of those terms was “Oxygen Absorber”. At the time, I had no clue as what they were and how to use them.

Oxygen absorbers, also known as O2 absorbers, are a mystery to many. Not a week goes by when I am not asked for guidance as to how to use them. Rather than answer those questions individually, today I am sharing an updated printer on oxygen absorbers with just enough information to get you started on the road to successfully storing bulk foods for the long term.

Food Storage Basics Oxygen Absorbers - Backdoor Survival

Learning about Long Term Storage

The very first item I purchased for my food storage pantry was a 25 pound sack of pinto beans. Of course back then, I thought I would simply store the big bag in the garage and let it sit there until I needed it. Set it and forget it. Why not?

Luckily, I did my research and learned first and foremost that beans, along with many other bulk foods, have a shelf life. Furthermore, I learned that beans will become hard as rocks if not properly packaged and stored in a cool, oxygen and moisture free environment. Who knew?

The light bulb really came on as I was reading John Hill’s book How to Live on Wheat. It was this little book that taught me not only about wheat (did you know that wheat can be living or dead?) but about storage containers, Mylar bags, desiccants, and something called oxygen absorbers. This set me on a serious path to learn what was in those little O2 absorber packets along with what I needed to do to use them effectively for long term food storage.

What the Heck are Oxygen Absorbers?

The first thing I learned was that oxygen absorbers are smallish little packets that hold an iron powder. Through the magic of technology, or so it seems to me, the outer wrapper lets oxygen and moisture in where it is absorbed by the iron powder. It does so while maintaining the integrity of the outer wrapper while at the same time preventing leakage of the the powder back into the packaged food.

Food Storage Basics: Oxygen Absorbers - Backdoor Survival

In the process of sucking up moisture, the iron in the O2 absorber begins to rust. This creates oxidation and before you know it, in a well sealed container, 99.99% of the oxygen is used up. Any space or air left in the container is nitrogen, not oxygen, which is not a bad thing because insects can not thrive in pure nitrogen.

In simplistic terms, those little packets of iron suck up all of the oxygen from the air within the container in which it is placed.

Factoid: Air is about 21 percent oxygen, 78 percent nitrogen and 1% other gasses.

What About Storage Containers?

As you do your research, you will hear over and over again that you should use oxygen absorbers in sealed Mylar bags. This is true. O2 absorbers work extremely well when used with sealed Mylar bags. That being said, they can also be used to successfully block out oxygen with other types of packaging, too.

All of the following will work:

Metal Cans with Sealed Lids. Great if you have access to a canner or a local community kitchen. For most of us, however, this is not a realistic and cost effective solution.

Mason Jars and Canning Lids. This is one of my favorites especially since I have a special jar attachment for my food saver that will vacuum seal mason jars quickly and easily. It is just a personal thing, but I love looking at my food peeking out of those glass jars.

Mylar or Metalized Bags. These are heavy duty foil bags lined with a special plastic.

Vacuum Sealed Bags (such as the Food Saver bags). While not as heavy as the Mylar, these are much easier to handle especially if you already have the Food Saver machine itself. Note, however, that vacuum sealed bags do tend to loose their seal over time although they should be good for up to 3 years.

Plastic Buckets with Gamma Seals. These can be used alone or in combination with other Mylar or other bags such as those from the food saver.

PETE Plastic Bottles. These are great as long as they include airtight, screw on lids.

The Proper Way to Use Oxygen Absorbers

There are a few precautions you need to be aware of when using oxygen absorbers.

The most important precaution is to limit the exposure of unused packets to air. Take out only what you are going to use in the next 15 minutes or so and seal the rest up in a jar with a screw top lid. Don’t put them in a zip lock bag because they will immediately suck up the residual oxygen and become useless.

A good rule of thumb is to use one 300 cc oxygen absorber for each gallon of product. For larger containers, you can purchase larger, 2000 cc oxygen absorbers which are ideal for 5 or 6 gallon buckets.

Be mindful of the little pink pill. Most reputable vendors will include a little pink pill with their package of absorbers. If the pill is blue, the absorbers are toast so don’t use them. However, if they are just starting to turn – not quite pink and not quite blue – they are probably okay since the change of color can happen in as little as 10 or 15 minutes.

Another good test of their viability is to pick one up an hold it. It may feel warm. It will also feel soft and powdery, like a little pillow. If it gets real hot and uncomfortable, it is in full out working mode and has probably been exposed to the air for too long to be usable. In this case it may also start to feel hard and brick like. Toss it.

Oxygen absorbers themselves have a limited shelf life, even when sealed. Only purchase an amount that you will use within a year.

7 Additional Tips for Using Oxygen Absorbers

1. If you decide to do some research on your own, prepare to be confused. You will find that some sources recommend you should use a larger quantity of oxygen absorbers when packaging dried pasta and beans versus packaging grains, flours, and rice. The reason for this is that the latter are more dense so there is less oxygen to get rid of.

As I read those tables showing how many O2 absorbers to use for this or that, my head starts to hurt. You can come to your own conclusion but the overwhelming advice I received from respected vendors was that 300 cc’s per gallon or 2000 cc’s per bucket would do just fine.

2. Almost anything can be packaged using oxygen absorbers and they are so inexpensive, there is no reason not to use them. There are two things, however, that should be packaged without them. They are sugar and salt. Why? Sugar will turn to a brick of concrete and the salt simply does not need anything special to keep it preserved. It might also clump.

3. Sprouting seeds need oxygen to stay alive and to ultimately germinate. This means that you will be defeating your purpose if you seal them up with an oxygen absorber. Don’t.

4. A bag sealed with product plus an oxygen absorber may or may not turn brick like in a day or two or even up to a week. The ability to fully compress is dependent upon factors such as head room and the amount of air that was sucked out during the sealing process.

This is not a problem in spite of what you may read on the internet. If you have used an oxygen absorber sufficient for the size of your packaging, the oxygen will be gone. The extra air is simply nitrogen and it will not harm your food. Of course, if it makes you feel better, you could open the package and start all over again but that is not really necessary for anything but your peace of mind.

5. When using a mason jar to seal bulk foods for the short term (one or two years), there is no need to use an oxygen absorber since your food will remain fresh for a few years on its own. On the other hand, the O2 absorber is low in cost (ten cents give or take) and provides an extra layer of protection.

6. Do not confuse oxygen absorbers with desiccants. The oxygen absorber removes oxygen and the desiccant removes moisture. You can use both although some foods are inherently dry to begin with and once vacuum sealed, will stay that way making their use superfluous especially if stored in a dry area.

7. During your food storage session, get everything set up in advance, assembly-line style. By that, I mean set up your packaging material (most likely Mylar bags or mason jars), fill them with product, and then, at the last minute, take out the number of O2 absorbers you need. Before moving down the assembly line, immediately seal the extra, unused O2 absorbers in a lidded mason jar or vacuum seal bag. This will ensure that they will still be viable for the next food packaging session.

Additional Resources

There are many articles on Backdoor Survival that can help you manage your food storage. Here are a few to get you started:

Survival Basics: The Six Enemies of Food Storage
Survival Basics: Buckets, Lids and Gamma Seals
Survival Basics: Using Mylar Bags for Food Storage
16 Food Storage Tips for the Space Challenged Prepper
14 Common Food Storage Mistakes and Goofs

For a more detailed and comprehensive handbook on food storage, be sure to check out my book, The Prepper’s Guide to Food Storage, that can be purchased on Amazon. The e-book is only 99 cents and the print version is $5.99.

The Final Word

There is no reason that oxygen absorbers should be a big mystery. The reality is that they are a cinch to use and inexpensive to boot.

Using them will pretty much guarantee that your bulk foods will stay fresh over the long term and as you know, you simply can not beat the cost-effectiveness of bulk foods. Wal-Mart, Costco, and LDS Home Storage Centers sell bulk foods at reasonable prices and with a little bit of work on your part, can provide you and your family plenty to eat when grocery store shelves are bare.

For an interesting technical discussion of Oxygen Absorbers, read A Guide to Oxygen Absorbers.

Note: This article has been re-written and updated from the original version that was published in August 2011.

Until next time, keep on prepping!

Enjoy your next adventure through common sense and thoughtful preparation!

If you enjoyed this article, consider voting for Backdoor Survival daily at Top Prepper Websites! In addition, SUBSCRIBE to email updates and receive a free, downloadable copy of my e-book The Emergency Food Buyer’s Guide.

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Bargain Bin: Here are some of my favorite food storage items. Whether you are just getting started or a seasoned pro, here are the items you will need when purchasing food in bulk for long term, storage needs.

Mylar bags & Oxygen Absorbers: What I love about Mylar bags and oxygen absorbers is they protect against every single one of the food storage enemies. Prices do vary but for the most part, they are inexpensive and easy to keep on hand. And while you can seal them up with a FoodSaver, some tubing and a common clothes iron, I find it infinitely easier with a cheap hair straightening iron that you can pick up $20 or less.

60 – 300cc Oxygen Absorbers: This is one area where you want to make sure you are getting a quality product. Currently, a pack of 60 (in three 20 unit packs) is about $10 with free shipping.

Ball Regular & Wide Mouth Jar Storage Caps: I must have 30 or 40 of these. I love to use mason jars for panty storage and for those items I go through quickly, I see no need to use the vacuum seal gizmo that goes with my FoodSaver.

FoodSaver Vacuum Sealer: As long as the unit has an accessory port (and this one does), an in expensive FoodSaver will work just as well as the fancier models. That is my two cents, at least.

FoodSaver Wide Mouth Jar Sealer: Already have a FoodSaver? If so, check out this jar sealer which can be used to vacuum seal your Mason jars. This is a great option for short to mid term storage of items such as beans, rice, sugar and salt. Store your jars in a cool, dark place and you are set with the added advantage of removing a small amount for current use without having to disrupt your large Mylar bag or bucket of food. There is also a version for regular sized jars. See Fast Track Tip #4: How to Use a FoodSaver for Vacuum Canning.

Sharpie Permanent Markers: Sharpies were invented for preppers! And without question, Amazon is the cheapest place to buy them. Typically, the price on Amazon is less that $7 for a dozen.

Conair Ceramic Instant Heat 2″ Straightener: An inexpensive hair iron such as this one is perfect for sealing Mylar bags. It can also be used on your hair so it can serve a dual purpose. For an even cheaper alternative, consider this one that works equally well but has smaller blades.

Nesco 600-Watt Food Dehydrator: This modestly priced dehydrator (less than $60) has over 1000 reviews and comes up as the most highly rated dehydrator on Amazon. I wish I had started out and learned the ropes with this unit rather than the more expensive Excalibur which did not work out for me.

How to Live on Wheat: I always wondered why wheat was recommended for food storage. This well-written book will teach you everything you need to know about wheat. Recipes included!

Prepper’s Guide to Food Storage: This modestly priced book is about food: What to store, how to store it and best practices. It is a roadmap for showing ordinary citizens that long-term food storage is not something that will overwhelm or burden the family budget. A lot of material from Backdoor Survival is here; conveniently located in one place. I wrote this book and am proud of it.


Shop the Emergency Essentials Monthly Specials: The monthly specials at Emergency Essentials feature discounts of up to 35% off sometimes a bit more.

A good value is the Do It Yourself SuperPail Combo which includes 8 x 6-Gallon Buckets with Lids, 8 x Metallized Storage Bags and a 10-Pack of Large Oxygen Absorbers.

Don’t forget that you do not need fancy equipment to seal the metalized bag. A cheap hair iron will do the job.  Forget about a hose and a vacuum sealer. A $20 hair iron works great – just be sure to get one with 2” plates.

Storing Rice in Mylar Bag_09


Need something from Amazon (and who doesn’t)? I earn a small commission from purchases made when you begin your Amazon shopping experience here. You still get great Amazon service and the price is the same, no matter what.

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Survival Basics: Using Oxygen Absorbers for Food Storage — 41 Comments

  1. Why are mason jars that are vacuum sealed short term storage? And do you need to use a vacuum sealer if you are using an oxygen absorber in the mason jar?

    • Marilee – Using a vacuum seal on your jars will ensure that the lid is properly sealed down tightly so that no air intrudes from the top of the jar. As a matter of fact, once sealed in this manner, you need a spoon or other tool to pry off the lid. It will be extremely tight.

      There is no reason your sealed jars with an oxygen absorber could not be used for long term storage. The oxygen absorber is simply another layer of protection.

      On the other hand, for short term storage (one or two years), there is no need to use an oxygen absorber since your food will remain fresh for a few years on its own.

    • Actually, it is because vacuum sealing doesn’t get all of the oxygen out of the jar. So some say they aren’t for long term,10+ years, storage. However, the amount of oxygen in the air is around 20-21% and if you removed most of the air from a jar there really is very little oxygen left. So personally, I don’t worry about it.


  2. thanks for the info. I have been wondering the whys and wherefores of oxygen absorbers. With respect, I still don’t see a reason for using them. My food storage is completely turned over within a 5-7 year period and I have never had a problem unless it in my learning phase AND the experiments as new technology came onboard.
    I used to store in metal cans, fortunately food grade plastic was developed although the shelf life of these isn’t known, living in the Pacific NW where humidity plays a big part in storing stuff, my cans corroded faster than what I put in them.
    I learned to use food and/or spices to do the work since I store those too. I use sugar, salt in a sock bag plus some bay leaves and peppercorns have worked for me these 40 years; so I will continue to do so until I am given something better. (Not saying anything bad about ‘absorbers’ just that if there is one thing I’ve learned in my 60+ years, it’s that not all that is ‘new and improved’ beats what has been traditionally used. We are, after all, a consuming society these days and I stepped off that track many years ago.
    As to the beans, I so agree. Rotate and use. If you are buying grain seeds like wheat, oats, etc. rotate too, and along the way, plant some of those seeds so you know how; if collapse should last longer than my 5-7 years, I want to be planting what I’ve stored for more food by then. When thinking long term, what happens when your ‘modern’ (sorry can’t think of another word right now) convenience stops working or runs out? I have lived in ‘modern’ places, only to have to move to more ‘primitive’ places where knowing how to live under almost any conditions helps these days.
    As to prepping, I am now, because I have obtained one of those flat iron hair straightners for which I am now creating my own spice blends for my health and for food preparations for those hard times. I’m labeling these and will also be rotating these, perhaps faster than I would other foods, but I’m using the chocolate chip mylar bags that aren’t costing me anything and saving since they aren’t going into the garbage either. In doing so, I am avoiding the chemicals which I don’t eat now either.
    I WILL however be buying some fd and dehydrated items which I just don’t have time to make but which I would miss greatly, like cheese and butter. 😉 and other foods which cannot be grown locally but are keeping me healthier than if I didn’t have them, like pineapple. :)
    Even though I do things a bit differently, I am so appreciative of all I am learning through your website, keep it up. :)

    • Hi there,

      60 yr.old grandma here. I’m kind of new to the prepping thing so I am trying to learn a lot. I have a few questions and if you feel like it, I would greatly appreciate an answer. You mentioned “chocolate chip bags”. What are those? Also, you mentioned putting up some “cheese and butter”. How is that done? . What is the shelf life for things that are put in mylar bags? Do you think it would be a good thing to encase (in the mylar bags) things like baking soda, baking powder, etc in mylar bags and in doing so, would buy me some additional shelf life? I have spent a lot of time creating lists and I find that being concerned about foodstuffs not only occupy the majority of my money, they also monopolize the majority of time.

      Thank you in advance,

  3. I’ve recently learned that while oxygen absorbers aren’t expensive, hand warmers are even cheaper and can be bought in lower quantities, eliminating the problem of securing leftover absorbers. So what do hand warmers have to do with food storage? They have the same ingredients and effect as absorbers when activated! Check it out!

  4. I’m curious about the 100 oxygen packs. If I’m packing something in a pint or quart mason jar, will 1 – 100 pack work or should I use more? What do you use for smaller quantities?

  5. This is great, Thank you so much for really explaining the how, why, and how much of the absorbers. I have been frequenting a handful of Prepper/Survival/Food Storage sites, and they all say to use them, but none have said how much or anything else.
    Love your site!!

  6. I don’t understand why sealing absorbers in a ziplock bag would be any worse than a Mason jar for storage. It would seem to me that there’s about the same amount of oxygen hanging out inside of both.

    • It is pretty difficult to get an airtight seal with a Ziploc. On the other hand, mason jars can be sealed so that they are impervious to oxygen and air in general.

  7. Also, you’ll be just fine putting absorbers in with seeds to preserve them. In fact, rendering them dormant by taking away oxygen is exactly what you’re trying to do. When you want to plant them, take them out and they’ll have access to oxygen again and have no problem germinating.

  8. a friend of mine gave me a candy boxes from Taiwan with “warm sachets” called O-Buster. I have no idea what it all about or why the manufacturer included such things. After consuming the candies I gather all this hot sachets and put it in the box with .45 Cal ammunition thinking it will ward-off moisture from the ammos. When I check it the next 2 or 3 days, the sachets hardened and not longer warm as it used to be. So I just put in trash bin for disposals.

    • putting the Oxygen absorbers in the ammo can is useless the way and manner you describe. Re-read the article, and I believe you will then understand. Good Ruck.

  9. Love your article. It is really informative and has loads of info I havent seen elsewhere! And yes I have looked! I love my straightening iron/ mylar sealer. This is its only use. I love that I can buy only one gallon size mylars and make my own smaller sizes with the iron. It works great!!! BTW, The pasta problem I have encountered only seems to be with the curly spiral types or the ones with holes through them like elbow and penne. They still seem to work… just take a lot longer sometimes.

  10. I read that you should not put an oxygen absorber in with sugar or salt. Can you tell me what other items that should not be stored using the oxygen absorber?

  11. As a Pharmacist for 35 years, I noticed almost every bottle of pills I opened had a “dessicant” packet it it. Since my retirement I have been becoming more self-reliant and self-sufficient. I ordered a bucket of dessicnat packs and included them in my Food Saver vacuumed sealed pinto bean bags (2 cups each bag) QUESTIONS: Will the desicant packs do the same as an O2 Absorber packet? will it hurt to put BOTH in a mason jar or vacuum-pack bag? I am new to this but now have the time and place to prepare for when SHTF. THANK YOU

  12. Here’s an “outside the box” question. I’m new at this but I’m reading that there’s a big hurry to use the oxygen absorbers once the package is open. I do some MIG welding and routinely use bottles of argon – a common inert gas. Since it’s heavier than air and is also used in the wine and home brew industries to flush oxygen out of barrels and bottles, what if you . . . 1) in an open garage out of the wind, 2) run a hose from a bottle of argon down into a 5 gallon bucket and turned the gas on very low, 3) put the un-opened bag of oxygen absorbers into the bottom of the bucket and opened it, 4) keep the absorbers in the 5 gal bucket, taking them out one at a time as needed, and when done, 5) put the remaining absorbers into a mason jar and seal it – doing it at the bottom of the inside of the bucket in the argon rich environment. Would this procedure not preserve the oxygen absorbers during the process and allow you to store the remaining ones in an argon rich environment inside the glass jar? Or am I over thinking this? Thanks!

    • JDS – Yes, definitely making too much work out of the process. Really, all you need to do is exercise some care and remove the O2 absorbers you will be needing in the next 10 minutes or so and put the rest back into a mason jar with the lid tightened. Rinse, lather, and repeat.

      It helps to prep your food in advance. Line up the filled Mylar bags, add the oxygen absorbers then seal them up in an assembly line process. Easy peasy.

  13. I really enjoyed the article and comments here. I have a question: Is it ok to use a 100cc oxygen absorber in a quart canning jar with dry rice or beans and then immediately use the Food/Game Saver vacuum machine with a regular or wide mouth lid attachment?

    I ask because on a survival forum I said that is what I was going to do and one poster said DO NOT use both because the oxygen absorber needs oxygen to activate it and work. I think it would be a good idea to use both as the vacuum machine doesn’t get all the oxygen out. What say you?

    • The oxygen absorber needs oxygen to work? Uh no, not quite. A better way of putting it is that the O2 absorber will activate itself when oxygen is present.

      Let me explain. When sealing a mason jar with a FoodSaver, you need to leave some headspace in the mason jar. Plus, food saver seals are not 100% perfect and over time may leak. The purpose of the oxygen absorber in the jar is to remove any residual oxygen, however small. Plus, the O2 absorber will pretty much guarantee that the seal holds.

      Try this for an experiment. Put some beans in a mason jar along with an O2 absorber. Seal the lid down with a standard mason jar ring. Come back in a day or two and the jar will be sealed without the use of a FoodSaver.

      The combination of the FS and the O2 absorber is simply a fail-safe. You KNOW the seal will hold and your food will stay fresh.

  14. Thanks for publishing article and comments. About two years ago I couldn’t make up my mind about O2 absorbers so didn’t buy any; but they did come in some freeze dried pails I bought. I did get an Excaliber Dehyrator and experimented with tomatoes, cukes, and a few other items. I was not totally prepared for hard chips (very dry) of tomatoes, though they tasted good. I put them in plastic zip lock bags, with as much air pushed out as possible, and put the bags into Folgers red-plastic containers (to avoid light); and they are still hard, crispy and taste just like the first day, now two years later. For me that is good enough, since the vegies keep growing every year. I’m not dismissing the use of O2 absorbers, but I still do not understand what usage they are most desirable for use, when I think I am already covered using dehydration, and when a full two years of storage by plastic bag sealing and light sealing is working soo well.

    • Many foods will become rancid over time without the use of an O2 absorber. This often is dependent upon both climate and the quality of the food to begin with. Also, the lack of oxygen will prevent any bugs/bug eggs from hatching and growing in your food.

  15. Can I put the unopened bags of rice in a 5 gallon bucket, lay the packets on top and seal the bucket. As you can guess I am new at this.

    • Julia – What you are going to want to do is slit open the bag or bags of rice and either dump the rice in bucket or set the open bags in the bucket. Bury your O2 absorbers in some of the rice and then close the lid. Note that if you open the bucket, you will need to add a new O2 absorber before closing it up again.

      You can also repackage the rice in smaller Mylar bags with O2 absorbers and stack the individual bags in the bucket. That way you can remove them one at a time as needed and not worry about adding a new O2 absorber each time.

      Congratulations on getting started. We were all new at one time or another :)

  16. Hello,
    I used my absorbers last night a few times ended up opening the ball jar. Each time I resealed with the food saver. Some of them got hot and when I opened the jar an hour later it was wet inside. This is the second time this has happened. First time I put them in rice in a jar and they all got hot. What am I doing wrong?
    Thank You

  17. I am so sorry this happened to you, Debbie, because the same thing happened to me once. I chalked it up to a bad batch of O2 absorbers. I was very mad because that is simply not supposed to happen.

    Were your oxygen absorbers all from the same original batch? Or separate purchases? I really want to get to the bottom of this because if it happened to me and happened to you, it will happen to others.

    • We had this same thing happen this morning (heat, then moisture accumulating in jar without lid). Jar was not vacuum sealed.

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