Oxygen Absorbers for Long Term Food Storage

Last Updated: March 22, 2023

Even non-perishables like beans and rice will eventually become bad if exposed to oxygen. If you want to store food long-term, you’ll have to protect it from oxygen. Luckily, there’s a cheap and easy solution: oxygen absorber packets.

What Are Oxygen Absorbers?

Oxygen absorbers are little packages containing iron. When you put the oxygen absorber (OA) into an airtight container, the oxygen molecules “stick” to the iron. OAs can reduce the amount of oxygen in a container to less than 0.01%. (1)

Remember that air is about 78% nitrogen, 21% oxygen, and 1% other gases. Oxygen absorbers only remove the oxygen. However, nitrogen does not cause food to spoil.

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Benefits of Using Oxygen Absorbers:

  • Keeps food from degrading due to oxidation
  • Prevent mold and bacteria from growing on the food (mold and most bacteria* require oxygen to grow)
  • Preserve flavor
  • Prevent vitamins from being destroyed by oxidation
  • Kill pests (tiny pest eggs that are invisible to the eye may be on your food; without oxygen, they cannot hatch)

*See the section on botulism in the FAQs

How to Store Food with Oxygen Absorbers

To store food with oxygen absorbers, you will need to put the food and oxygen absorbers in an airtight container. If the container leaks air, it is pointless to use oxygen absorbers. There are four main containers that can be used for long-term food storage with oxygen absorbers.

1. Mylar Bags

Mylar is a metallic-looking material that doesn’t allow air or humidity through. Mylar bags are very cheap and durable, making them one of the best long-term storage packages for dry food.

To store food in it, you will fill up the Mylar bags with dry foods, add oxygen absorbers, and seal the bags. You can then put the Mylar bags in buckets with lids. This will keep food safe against virtually any disaster. Some people even do “Mylar bag parties” with friends so they can seal a lot of food in one go.


  • Protects against light
  • Virtually indestructible when bags are put into buckets
  • Cheapest long-term storage option
  • Bags come in many sizes


  • Slight learning curve
  • Cannot see food inside bag

For detailed instructions, see our post on mylar bags for food storage.

To buy high-quality Mylar bags, check out Wallaby.

2. Canning Jars

oxygen absorbers in mason jars

For storing smaller amounts of food long-term, you can put the food in canning jars or Mason jars (jars with a two-part lid). Just add the right amount of oxygen absorber to the jar and then screw on the lid. You’ll know the oxygen absorbers are doing their job because the jar lid will get sucked down.

Other jars can also be used with oxygen absorbers. However, the lids on these jars are much more likely to leak. Play it safe and stick to canning jars.


  • Very easy
  • Rodent-proof
  • Easy to rotate food


  • Jars are breakable
  • Only hold small amounts of food
  • Don’t protect against light

3. Buckets

gamma lid

The simplest way to use oxygen absorbers with large amounts of food is to put them into food-grade buckets.   You fill the bucket with dry foods, add the right amount of oxygen absorbers, and then close the lid.

The downside is that most buckets will leak air inside. This includes the cheap HDPE 5-gallon food-grade buckets. They slowly leak air, so you could still use them with oxygen absorbers – just not for long-term storage. You are much better off with a gamma-seal lid bucket. These buckets cost more but do create a tight seal.

Also, note once you open the bucket, you will expose the food to air. If you want to reseal the bucket, you’ll have to add more oxygen absorbers.

So, this method isn’t suitable if you plan on rotating through your food stockpile. I’d only recommend using buckets as a short-term solution until you get enough food stockpiled to have a “Mylar bag party.”


  • Can easily store large amounts of food
  • Buckets are durable


  • Most buckets leak air through lid
  • Will expose food to oxygen each time you open the bucket
  • Gamma lids are a bit pricey

4. #10 Cans

Many emergency foods – like butter powder from Augason Farms or Mountain House’s scrambled eggs – are packaged in #10 cans (pronounced ten-pound cans). If you get a can sealer, it’s possible to store your food in these cans at home too.

Using #10 cans for food storage is pretty simple. You just put your dry food in the cans, add oxygen absorbers, and seal the can. The seal is completely airtight, and the cans are tough enough to withstand almost any disaster.

The downside is that the cans and the sealer are pretty expensive. If you are lucky enough to know someone who already has a can sealer you can borrow, you only have to worry about the cans’ costs.


  • Disaster-proof packaging
  • Protects against light and physical damage
  • Smaller quantities of food per can make use and rotating easier


  • Cans and sealer are expensive
  • Only can store small amounts of food per can

How Many Oxygen Absorbers Should I Use?

Oxygen is in the food container in two places:

  1. In the space between the food
  2. Inside the actual food

You’ll need to remove virtually ALL of this oxygen to keep the food safe for long-term storage. This means making sure you use enough OAs.

Below is a general guideline of how many oxygen absorbers you will need. However, the amount can vary depending on whether your batch of beans is uniform (lots of air space between the beans) or varying in size (less space between the beans).

You’ll need to do some math to know precisely how many OAs you need. I’ve included the math in the dropdown for those who are interested.


As Fresh Pack points out, there can be a surprising amount of oxygen within certain foods. For example, dry foods like TVP contain a lot of air. The same goes for dry beans.

They also point out that there is incorrect information about how density affects air amount. The idea that “items with small particles (like flour) are ‘dense’ and have less air volume” is FALSE. Here is why:

“A pool filled with marbles will have the same interstitial air volume as one filled with basketballs. Yes, the basketballs will have much larger pockets of air, but there are far fewer of them. Think of a checkerboard with just 2 large black and 2 large white squares… ½ of its area is black and ½ white. What if it had 100 small black squares and 100 small white ones? 1000? Even with tiny squares, it is still ½ black and ½ white as long as they are all uniform.

What does matter is particle size distribution, or in other words, whether you have particles that are all a uniform size or if you have a lot of particles of different sizes. If you have a pool filled with basketballs AND marbles, the marbles can fill in all the large air pockets. So, products with uniform particle sizes will have more interstitial air than products with a greater distribution of particle sizes.”

Calculating How Much Air is in the Container

To figure out how much air will remain between the food spaces in a filled container, you can do this test:

  1. Put 1 cup of product in a large measuring cup.
  2. Add 2 cups of water.
  3. See how many cups you get in total (the amount won’t be 3 cups because the water fills the spaces between the product).
  4. Calculate: 3 cups – (how many cups total you got)
  5. The answer is how much of the product was air. For example, let’s say you got 2.5 cups total: 3 cups – 2.5 = 0.5 cups. Since 0.5 = 50%, 50% of the product was air.

With this information, you can do a reasonably exact calculation of how many oxygen absorbers you need. This requires some more math:

  1. Figure out how much air your container holds. For example, a 1-gallon Mylar bag holds 3785 cubic centimeters (cc’s). A pint jar contains 100cc of air when empty.
  2. Determine how much air will be left in the bag once filled by product. For example, if you determined that 50% of the product was air, you’d have 1893cc of air space.
  3. Only about 21% of air is comprised of oxygen (the rest is mostly nitrogen). So, calculate 21% of your air space. For example: 0.21x1893cc= 398cc.

*Some products like beans contain a lot of air inside of them. For the water test to work, you have to let them sit for at least 6 hours, so they absorb the water. Beans also require a lot more oxygen absorbers than typically shown in charts.

Food Type1 quart1 gallon5 gallon
Beans, lentils, split peas125-150cc500-600cc2500-3000cc
Instant mixes and powders100cc400cc2000cc
Coffee beans100cc400cc2000cc
Instant potatoes125cc625cc2500cc
Whole grains (barley, corn, wheat, oats)125cc625cc2500cc

Top Tip
It is always best to play it safe – use more oxygen absorbers than you think you need! Using extra oxygen absorbers won’t impact the food. OAs are cheap; better to spend an extra 25 cents on an additional oxygen absorber than throw away 5 gallons of food when it’s needed most.

What Foods Can Be Stored with Oxygen Absorbers?

Just about any dry and low-fat food can be stored with oxygen absorbers. This includes foods like:

  • Flour
  • Whole grains
  • Pasta
  • Dried beans
  • Powdered milk
  • Cereal
  • Freeze-dried food
  • Spices

Note: Not all foods are oxygen sensitive. For example, whole grains, peas, and beans aren’t too oxygen-sensitive. If you plan on using the foods within 5 years, there won’t be too much difference in freshness regardless of whether you use an OA or not.

However, oxygen absorbers do protect against pests and have other benefits, like preserving nutrition. Since OAs are cheap, I recommend using them with all dry foods you want to store for 12+ months.

Dehydrated Food with Oxygen Absorbers

Most home-dehydrated fruits and veggies usually aren’t suitable for long-term storage. They simply contain too much moisture. If the moisture level is too high, you could even risk botulism poisoning (more on that below).

To safely store dehydrated food with OAs, it must be so dry that it snaps when bent. Or, for round foods like corn or peas, it should shatter when pressed with a spoon.

*Read Expert-Level Food Dehydrating

Nuts and Seeds with Oxygen Absorbers

Storing nuts and seeds with oxygen absorbers will extend their shelf life. However, they will eventually become rancid because they contain so much oil.

Most people put the shelf life of nuts/seeds with OAs at about 2 years. However, nuts and seeds can last longer than this, even when exposed to oxygen. The key is keeping the temperature and humidity low.

*Granola also has a lot of oil and won’t store long-term.

Foods that Should NOT Be Stored with Oxygen Absorbers

  • Salt: Will become rock hard if stored with an OA
  • Sugar: It also will become rock hard; brown sugar also contains too much moisture for storage with OAs. Read how to store sugar for the long term.
  • Wet foods: Foods with 35% or more moisture can grow botulism in airless environments. It is recommended that foods stored with OAs have 10% or less moisture to play it safe.
  • Baking soda, baking powder, pancake mixes, and yeast: There’s some debate about whether OA can be used with these foods. Some claim that a chemical reaction could occur and result in the leavening products then becoming useless.


Botulism Risk

Botulism is usually only talked about in regard to home canning. However, because the botulism bacteria grows in no/low oxygen environments, it could also develop in Mylar bags packaged with oxygen absorbers.

Botulism requires moisture of 35% to grow. However, to play it safe, virtually all food preservation guides say that food must have 10% or less moisture to be packaged in airtight containers with oxygen absorbers. (2)

This shouldn’t scare you away from self-storing foods with oxygen absorbers. Ensure you aren’t storing any moist foods in sealed containers with oxygen absorbers.

The good news is that botulism toxin (which causes the disease) can be easily destroyed by boiling it for 10 minutes. The CDC states, “Despite its extreme potency, botulinum toxin is easily destroyed. Heating to an internal temperature of 85°C for at least 5 minutes will decontaminate affected food or drink.” This page also has helpful info on deactivating botulism. Many foods stored for the long-term need to be boiled anyway (dry beans, dry grains, etc.), so this, in theory, would kill any contaminants.

However, that doesn’t mean you should eat any foods which you suspect are contaminated with botulism.

Warning:  If the package is bulging (a sign that bacteria or toxins are growing inside), don’t eat its contents!

Shelf Life of Foods with Oxygen Absorbers

Remember that OAs only protect against oxygen. You’ll also want to protect your food against heat, light, and physical damage.

The following table gives a general guideline of what shelf life you can expect when packaging food with oxygen absorbers.

Food TypeShelf-Life
Hard Whole Grains
(Dry corn, buckwheat, soft white wheat, durum wheat, spelt)
10+ years
Soft Whole Grains (Oats, quinoa, rye, barley)8+ years
Professionally-Dehydrated Vegetables10-20 years
Professionally-Dehydrated Fruits*10-15 years
Home-Dehydrated Fruits and Veggies*2-5 years
Freeze-Dried Fruits and Vegetables25 years
Legumes (Beans, lentils, chickpeas, split peas)25+ years
White Rice10-30 years
Brown Rice2-5 years
White Flour10-15 years
Whole-Wheat Flour10 years
Corn Meal5-10 years
Potato Flakes30 years
Pasta20-30 years
Dry Non-Fat Milk15 years
Cheese Powder10-15 years
Powdered Eggs5-10 years
Nuts1-5 years
Granola1 year
TVP10-15 years

*Dehydrated fruits and vegetables must have less than 10% moisture to store with OAs safely. They will snap when bent or (with round food like corn) shatter when pressed with the back of a spoon.

How to Store Unused Oxygen Absorbers

The moment you take oxygen absorbers out of the package, they will start to absorb oxygen. After around 2-4 hours, they’ll have absorbed their maximum oxygen capacity.

You must plan what to do with any unused oxygen absorbers before you begin working. Ideally, you will reseal oxygen absorbers in the packaging they came in. Then you vacuum seal them.

If this isn’t an option, you can also store unused oxygen absorbers in a mason jar. Fill up any extra space in the jar with marbles (or something similar). The less air in the jars, the less air the unused OAs will absorb.   Be sure to seal the jar tightly!

How to Tell If Your Oxygen Absorbers Are Still Good

If you buy OAs from a reputable company, they should be good. We like the supplier Wallaby Goods; they are good value and provide high-quality products.

They will arrive in a vacuum-sealed package. Most oxygen absorbers have a “margin for error” added to their abilities. So, they will absorb more than specified.

This is so you can have 10-20 minutes to work with the OAs and not have that air exposure count against you.

Here’s how you can check:

  • They arrive in a vacuum-sealed package.
  • The oxygen indicator is pink or red and not blue.
  • The packets feel soft and not crunchy.

Oxygen Absorbers vs. Desiccants

Oxygen absorbers will absorb oxygen. Desiccants will absorb moisture. OAs require a small amount of moisture for them to activate. Thus, it’s generally not recommended to use both OAs and desiccants together.

There are some exceptions to this rule, though. Some foods (like home-dehydrated fruits) may contain a lot of moisture. Since moisture is one thing that makes food spoil, adding a desiccant can help the food last longer.

In this case, it’s best to use silica gel desiccants because they don’t absorb so much moisture that it will interfere with the OA. Some more advanced types of desiccants can reduce the moisture to practically zero, which means they would stop the OAs from doing their job.

*When using both oxygen absorbers and desiccants, put the desiccant on the bottom of the package and the OA on the top.

Oxygen Absorbers vs. Vacuum Sealing

Oxygen absorbers and vacuum sealing both work by removing air from the packaging. However, vacuum sealing doesn’t remove all the oxygen as OAs do. Also, the vacuum seal bags are not airtight and will slowly leak air into the package over time. Thus, vacuum sealing is NOT suitable for long-term food storage.

There’s also no reason to use oxygen absorbers and vacuum sealing together: OAs do their job well enough without any need to first suck out air. Further, the vacuum sealer will remove nitrogen from the packaging (oxygen absorbers only remove oxygen). If you add an OA to a vacuum-sealed bag, the bag may get so “sucked in” that sharp edges on foods like rice could tear through the bag.

This doesn’t mean that vacuum sealing isn’t suitable for food storage. Vacuum-sealing can increase the shelf life of foods by 3-5 times. It’s also great for storing foods unsuitable for OAs, such as moist foods. But, when you want long-term storage (5+ years), sealed containers with oxygen absorbers are the way to go.

Oxygen Absorbers vs. Gas Purging/Nitrogen Flushing

I’ve recently found many guides and videos about gas purging (aka nitrogen flushing) Mylar bags. The basic idea is to use a special machine to force nitrogen gas into the package. The nitrogen flushes out any oxygen. Then you seal the package, so only nitrogen remains.

Some food manufacturers use nitrogen flushing to keep their greasy foods (such as chips) fresh for a long time. That’s why bags of chips are puffy when you get them.

However, nitrogen flushing is very difficult unless you have access to professional equipment! You must displace all oxygen and ensure none gets back into the bag before you seal it.

Packaging with oxygen absorbers is much easier and leaves just nitrogen in the packaging. Don’t mess with what works – use oxygen absorbers for your home food storage and leave nitrogen flushing to the experts.

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Strong bags with top-quality OA’s included. A good size for the average preppers’ needs.

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Leave a comment

  1. good overall article >>>

    but you have a mis- Q within the article >> it first indicates the 02 absorbers can prevent bacteria growth – then later it corrects itself by discussing moisture % and botulism >> not good

    you included what is often left out !!!!

    *When using both oxygen absorbers and desiccants, put the desiccant on the bottom of the package and the OA on the top.

    • Hence why I wrote after the bacteria line “most bacteria require oxygen to grow.” 🙂 Botulism is the exception. I’ll edit the article to make sure this is clearer. Thanks.

    • As far as I know, no – oxygen absorbers can’t be revitalized. They go through a chemical reaction when exposed to oxygen and the reaction can’t be reversed. Well, maybe there is some high-tech way a chemist could do it… In any case, even if you could reverse the process in OAs, I wouldn’t risk it; they are cheap and you don’t want your food to go bad because you took a chance with reusing old OAs.

  2. I recently put different types of beans and rice in glass jars with the locking clamp. Then added a oxygen absorber packet to each jar. I also put the extra absorbers in a glass jar. When I went to get one before, the inside of the jar was warm. Is that normal? Can I use OA to store dry pasta in jars?

    • It’s normal for OAs to produce a bit of heat as they work. The heat will go away after a while. If the jars are still hot days afterwards, the I don’t know what’s going on 😀

      Yes, you can use jars for storing dry foods like pasta, so long as the jars have a tight-fitting lid. However, I don’t advise on it. You can’t really fit that much pasta in a jar and jars can break. You are better off getting Mylar bags IMO. Save the jars for items you only need in small quantities, like spice packets.

      • Depending on the size of your jar & the size of your pasta, using glass jars for pasta is a better viable storage option, and in my opinion an excellent option for serving options. A quart jar will hold a little over 1.5# of pasta [this is regular size macaroni and regular size, broken to fit compactly into your jar spaghetti], . Also in jars, you don’t have to worry about the pasta breaking through a mylar bag which may necessitate adding an extra bag or brown paper bag [or other] type of shielding first. Once opened you can use what is needed fir the meal, and you have a ready-made, pest-free container to continue to store your product in.

        • All good points. As someone who lives in an earthquake zone though, I still generally don’t like the idea of glass for long term storage — definitely don’t trust my “earthquake proof” shelfing! 🙂

          • Buy some socks (or use worn out socks I suppose?) and place your jars inside of them. It will block out some light and keep your jars from smashing together. If things get real rough, you’ll also have some nice new socks to wear! You could also make cardboard sleeves for extra protection and light blocking, if you have a few extra minutes to spare…

      • Can you store dry goods in the old style canning jars (glass tops with wire bale). I have a good supply of these with new rubber seals, and the rims and tops are in excellent condition (no chips). I wouldn’t use them for any wet canning but it seems these would work well for dry goods. Will OA form a good seal with these? German made WECK jars work on the exact same principal as these old style jars and I would think that they would work for dry goods.

        • If the lid forms a good seal, then you should be able to use them with OAs. I personally don’t like the idea of storing any of my preps in glass though (there are earthquakes where I live). Also, the seal might eventually break so make sure you periodically check that the lid is still sucked-down looking. It’s generally good practice to check on your preps twice a year, such as during daylight savings time so it’s easy to remember.

      • Uline sells the most incredible boxes that come with inserts for protecting and storing quart canning jars. The boxes will hold up to 200 pounds and stack nicely but if in an earthquake prone area, probably not the best choice.
        Uline also sells a box for 2 quart size jars but with no inserts, although I have not found that to be an issue as creating my own inserts is easily managed. I use several sheets of plain paper which I may need if there are shortages.
        Jars are great for keeping food safe from moisture and rodents. They allow the use of foods in smaller increments in a time of need rather than having to open a bucket.
        BTW, if a rodent learns there is food in a bucket and has opportunity, it will chew through it. Be aware that plastic also “breathes”and can absorb moisture and chemicals that may be around it. Using a mylar bag on the inside would be prudent and store buckets off the floor.

        • Thanks for the tip. Those Uline boxes look great. I still hate glass for long-term storage though. Hurricanes and tornadoes also will destroy glass, not just earthquakes. I use small Mylar bags (kept inside large buckets) so I don’t have to open a massive Mylar bag if I need my emergency food. You can even cut large Mylar bags and seal the edges to create whatever size bag you want.

  3. Have you ever used(or heard about) vacuum sealed mylar bags? I bought some on Amazon. Just wondering what your thoughts are on these.

    • I personally haven’t done it, but I have seen hacks on YouTube which show how you can vacuum seal Mylar bags. The issue is making sure you get a proper seal on the Mylar bag since it is thicker than standard vacuum bags.

  4. With so many mylar bags on market. Do you have it written somewhere what yo look for? I know mil thickness are important. Some bags you get that say mylar you. An see through still. Thanks

    • We’ve got recommendations in this post https://www.primalsurvivor.net/mylar-bags-food-storage/ As for thickness, the thicker ones are more durable but can cut your fingers (they have sharp edges!) and don’t bend as much, so not as much food will fit in them. As a general rule, use slightly thicker bags for pointy things like rice and thinner bags for other stuff. If you put the sealed bags in buckets after you are done then you don’t really have to worry about the bags tearing or breaking.

  5. For long term storage, you recommend oxygen absorbers and sealing Mylar bags not oxygen absorbers and vacuum sealing Mylar bags?

    • Yes, I recommend Oxygen Absorbers + sealed Mylar bags (seal with an iron, hair straightening iron, etc.). It’s actually not easy to vacuum seal Mylar bags. There are hacks that allow you to do it, but usually the vacuum sealer doesn’t get hot enough to properly seal the Mylar.

  6. You talk about vacuum sealing removing the nitrogen. So, what happens to the dry food if nitrogen is removed with vacuum sealing – using mason jars/lids. I also put an oxygen absorber in the jar before sealing. My goal is long term storage 5 to 10+ years depending on type of dry food being stored.

    • Nitrogen doesn’t cause food to spoil, so it doesn’t really make a difference in terms of how long the food will last. The important thing is that you get the oxygen out (and of course also keep the food away from heat and light). So long as the seal remains intact, vacuum sealing in jars with good lids should give you a very long shelf life. However, I still personally prefer Mylar bags since they can hold a lot more food, are cheaper than vacuum-sealer jars, and you don’t have to worry about jars breaking during an earthquake/hurricane/etc.

      • Buckets with gamma seal lids are a good alternative. Empty ones with lids can usually be gathered at no cost from grocery stores with bakeries. Frosting comes in them. New Dawn dish detergent will remove the oil left behind. The gamma lids would have to be purchased separately if wanted. I suggest using a mylar bag on the inside with the oxygen absorbers.

  7. When storing flour, rice, corn meal, pasta, and flake potatoes, do you store them in their original packages along with OA,s?

    • Food in plastic bags should be taken out of the original packaging. The reason being that air might get trapped inside the plastic, and thus the OAs won’t be able to do their job. If the food is in a paper bag (flour), then you *could* keep it in its original packaging. However, the bag of flour won’t fit nicely in the Mylar bag anymore. That means lots of empty air space, so you’d need a bunch more OAs.

      In short: It’s best to remove things from their original packaging!

  8. I bought quite a f ew 300 cc oxygen absorbers a couple years ago. I am using them now but find the indicator stays pink. does not change even if taken out and left on the counter. they were stored in a bucket in a cold room. some feel hard. are these any good anymore?? how can I test them? thankyou

  9. Thank you for sharing all of your research and experience!

    The place I purchased my supplies from (Discount Mylar Bags) mentions needing to use a desiccant if the humidity is above 50%. I live in a very humid area (outside humidity is usually 70-90% and inside humidity is often above 50%). Would you agree with the need for a desiccant? If so, perhaps add that to your masterpiece of information. =) (I am personally planning on running a de-humidifier before doing my bags to avoid the question altogether.)


    • Using a dessicant is a good idea in humid areas or with foods that absorb moisture. Just keep the dessicant at the bottom of the bag so it doesn’t interfere with the Oxygen Absorber at the top.

  10. Can I put multiple mylar bags (smaller sizes), inside one of those 5 gallon food storage containers before sealing with a gamma lid?
    Thank you.

    • Put as many bags as will fit 🙂 I organize my buckets so each has complete meals. Like each bucket having carbs, proteins, fruits/veg and smaller bags with spice mixes in them. Other people do it so each bucket has the same thing, like one bucket containing just rice and another just beans.

  11. After my shopping spree, of mylar bags, OAs, a vacuum sealer, and mason jars, I came to a standstill; completely confused on which process for which food product. There are so many novice preppers giving contradictory advice. You are very succinct with your wealth of knowledge. Thank you 100x over!!

    • I am in the same boat as you. I’m confused. I just now learned that you don’t vacuum seal mylar and only use OA’s with mylar. I was looking up OA’s to put in with my vacuum sealed bags of rice and beans and flour. I’m confused! 🙁

      • It also states you can use OA’s in 5 gallon food buckets that have gamma lids (the kind the lid screws on, not snap on). Mylar inside of the bucket gives even better protection, it just depends on how long you plan to store, from what the article stated.

  12. Re: “packaged in #10 cans (pronounced ten-pound cans). ”
    For what it’s worth… a #10 can IS a Number 10 can, as in one of the 10 most common standardized types ranging from number 1 to number 10. There is even a clue in how it’s written… if it’s written as #10, then it’s number ten… if it’s written as 10# then it’s 10 pound(s). It has never had anything to do with direct measure of the contents, it’s always simply been the tenth size.

    I understand that it is commonly called a 10 pound can nowadays, but that’s simply from people misunderstanding and passing that along to others causing them to do the same thing. This is easily researched and verified from many reliable sources, some dating back to around 1900 when this system became a thing.

    I post this to help prevent more people from passing along this false nomenclature even longer. Author, if you read this, PLEASE PLEASE PLEASE update your article.

  13. How would you recommend storing several packs of things like Chicken Fried Rice (which comes in bags, or hearty soups which are also bought in packets? Should they be repackaged and OA added? Details please.

    • IMO, people should have two types of emergency food supplies. The first is a two-week supply. This supply is for short-term emergencies like blizzards, power outages, tornadoes, etc. Those foods you mention are fantastic for this supply because they don’t require lots of cooking (canned foods are even better). You wouldn’t want to crack open a 10lb bag of beans for a 3-day power outage! Just rotate through the foods in your 2-week supply and you don’t have to worry about repackaging. You could repackage them but it’s too difficult to estimate a long-term shelf life on these foods. The main issue is that they usually contain lots of oils, which will go rancid even in mylar with OA.

      The other emergency food supply is your long-term supply. This is for SHTF situations where you won’t have power or regular services for a long time. These foods are things like freeze-dried foods, dry grains, dry beans, etc. Those are worth repackaging in Mylar with Oxygen Absorbers, especially since you will be doing a lot of them.

  14. Nitrogen filled mylar bags AND OAs (just to make sure);

    Why is nobody else doing it and what would be the appropriate CC OA to use in a nitrogen flushed and loosely filled 5 lb mylar bag of dried pinto beans?

    Thanks so much for your help!

    • No one does that because it’s a lot of extra work. 🙂 Just do one or the other. After nitrogen flushing, you wouldn’t have much oxygen left in the bag of beans so theoretically fewer CCs of OAs would be needed. Unforunately, I don’t know the math behind that one. You’d have to calculate how much oxygen is INSIDE the beans. The “calculating how much air is in a container” steps will work for this, but you must let the beans sit in the water overnight to see how much water gets absorbed into the beans. Not worth the hassle IMO though.

  15. Another thing RE: food storage that I cannot find anything on is the use of mylar as a freezer wrapping for meat… why is that?

    Is mylar not a good freezer material for meats (or any other contents in the freezer)?

    Thanks again!!

    • Yes, you can use mylar as freezer bags. But there’s really no reason to. The freezer is the main method of preservation, so the mylar isn’t necessary. It would be more expensive than using cheaper freezer bags. You also generally don’t want to put Oxygen Absorbers in a sealed package in the freezer. It has to do with the fact that the food can sweat as it defrosts, thus create moisture pockets which in turn could grow botulism in an oxygen-less environment. If you do store meat in the freezer in Mylar, don’t use oxygen absorbers and make sure you use the meat as soon as you take it out of the freezer (don’t let it sit around in the mylar bag in the fridge thinking the mylar will keep it fresh).

      • Thanks for this brilliant article, and also for inadvertently answering a question here that I’d often wondered about – namely, why people always talk about freezing flour and rice for a few days to kill bugs BEFORE putting them into mylar bags with the oxy tabs. I could never understand why they didn’t just freeze them after they were all packaged up.
        I only have a tiny freezer so have never bothered to freeze things before bagging – it also worried me that it could make the rice or flour damp before re bagging it.
        I’m pretty sure that in a SHTF situation I could turn a blind eye to a few cooked bugs and bug poops anyway – and would prefer bugs to botulism any day!

  16. Thanks for the great info! To store dried pemmican for long periods of time in mason jars, do you recommend dessicant packets and/oxygen absorbers?

    • You can use either one. The general advice is not to use oxygen absorbers and dessicants together. You can do both though if the desiccant is on the bottom and the O2 absorber on top (not much separation room in a mason jaro though). However, the most important thing is that you keep the pemmican COOL. Heat will make fats go rancid, with or without oxygen. Rancid food won’t kill you but it definitely doesn’t taste nice.

  17. I would like to no if you can and I do put my dehydrated food in food saver vacuum bags, then I wrap them 3or4 times with plastic wrap do to some sharp edges if they should put a hole in the bag, then I put them in Mylar bags. Do I put OA in the vacuum sealed bags and some in between in the Mylar bags. Then I put them with locking handles in bins. Then in the bottom of the bins I put bay leaves to deter mice. No I don’t have any.
    Is this a good way to store food for long term short term?

    • This actually isn’t a good way to store food. If you put food in vacuum sealer bags first, the oxygen absorbers might not be able to do their job properly (remember that a lot of the oxygen in food is INSIDE the food itself. Vacuum sealing only removes air around the food and not within it).

      Just put the food in Mylar, drop an oxygen absorber in, and seal it up quickly. Put those in buckets to keep rodents out. It will be good for years.

      *Dehdyrated foods have to be VERY dry if you store them with OAs. Otherwise botulism poisoning can occur.

  18. For flour, is it okay to leave flour in the original packaging and place in the 5 gallon Mylar bags within a 5 gallon bucket or should the flour be poured into smaller Mylar bags? I had wondered the same for sugar.

    • Flour in paper bags can be kept in its original packaging. The oxygen absorber should be able to do its job through a paper bag, but not a metalic or plastic-coated bag. You won’t be able to fit as much in the Mylar bag though. There will also be lots more air space around the bag so you’ll need to use more oxygen absorbers.

      *Sugar should never be stored with oxygen absorbers. It doesn’t go bad ever. You can keep it in its original bag and seal it in a Mylar bag to keep insects out.

      • Thank you so much Diane. One more question. My flour in mylar bags never seems to have the air sucked out. I have tried adding more OAs but the bags never get “tighter” than when I originally sealed. This last time, I used a gallon Mylar bag, removed the flour from the original bag and use 2 – 1000cc OAs which I know should be too large. The OA pack still showed “pink” on the package and the package had never been opened. What am I doing wrong?

        • OAs don’t always make the bags sucked down looking because there is also nitrogen in air, which the OAs don’t remove. So you don’t have to worry about them still being a bit poofy. You’d have to ask a scientist about why some air apparently has a higher oxgen or nitrogen content 😀

  19. Can you store self rising flour in mylar bags with oxygen Absorbers? I get confused when I hear other people say you can’t store pancake mixes and Biscuit mixes for long periods…and also can you store seasoning mixes and bouillon cubes long term and if so how should you store them safely ?

  20. I have some dried goods stored already in vacuum sealed bags – mostly in smaller quantities to use as I go. Can I put the vacuum sealed bags right into mylar bags that are a close size/fit with O2 absorbers, or do I have to empty the contents from the vacuum sealed bags?

  21. Very confused I read to freeze rice and beans about 3 days , then let sit for a few (in original packaging), then do the mylar bag fill (w/o orig packaging), with oxygen absorber/in 5 gallon bucket. Is the freezing going to be an issue???
    Help and thank you!

    • The freezing is to kill any insect eggs which may be in the food. You do NOT have to freeze if you are using oxygen absorbers. Insect eggs can’t hatch without oxygen. If using OAs, just:
      -Dump the food into the Mylar bag
      -Partially seal the bag
      -Add an oxygen absorber (check the right amount to add)
      -Finish sealing the bag
      -Put in a bucket with lid. The bucket protects from physical damage, rodents, etc.

  22. This may seem a silly question, but being new to this, I’ll ask it. If you open a bag/jar to remove some contents, do you need to replace the 02 absorber before resealing it? I’m assuming so, but not sure. Can’t seem to locate the answer in my searches.

    • That’s exactly right: you need to add new OAs each time you open the bag. You can reuse the same Mylar bag — just need to be sure there aren’t any bits of food in the seal area when you go to reseal.

  23. Hi. I am making individual on the go just add warm/hot water meals for my family to place in bugout bags. I’m using mylar bags. Do I still use OA’s?

    • Yes, I would use OAs. They will extend the shelf life so you don’t have to rotate through the food as often. Otherwise oxygen will still be in the Mylar bag. It will go rancid faster and cause nutrients to deplete faster.

  24. I took a 25 lb bag of flour that had been in the freezer for maybe a month, sat it out for 3 or 4 days to bring it to room temperature, and afterwards divided it among five gallon mylar bags. I threw in a 500 cc oxegen absorber in each bag, and sealed them afterwards with a hot iron.
    A few hours later, the oxegen absorbers were doing their job, and being new to the whole long-term food storage thing, I was feeling quite proud of myself.
    Four or five days later, however, I began to worry about botulism. You see, I had put the flour in the freezer in its ‘original packaging.’ (I’ve since read reports that it shouldn’t be put in the freezer in it’s original packaging due to the possibility of condensation forming).
    I’ve done this on many previous occasions with smaller bags, but had emptied the contents directly into the flour canister. This time, I was putting the flour into mylar bags with oxygen absorbers. Moreover, as I scooped the flour into the bags, I noted a little flour was sticking to the bottom of the measuring cup as I dipped. I’m wondering, is it possible I might have inadvertently created conditions conducive to botulism?!
    Do I need to throw the flour out and start over? ☹

    • It’s fine to freeze the flour in its original packaging — you just have to make sure you let it sit and dry out before repackaging it (which you did). Botulism needs moisture of 35% to grow (though, to play it safe, don’t store foods with more than 10% moisture in oxygen-free environments). It’s highly unlikely that such a wet moisture pocket formed in the flour –even if it was sticking to the scoop.

      BTW, there’s no need to freeze flour first if you are using OA. Insect eggs won’t hatch without oxygen. You only need to freeze first if you are storing in buckets, jars, etc. without OAs.

      This should also put you at ease. While the bacteria that causes botulism is heat-resistant, the toxin produced by botulism (which is what makes you sick) is easily killed with heat. If you are still worried, just bake something with the flour. No need to dump it.

      According to the WHO:

      “Though spores of C. botulinum are heat-resistant, the toxin produced by bacteria growing out of the spores under anaerobic conditions is destroyed by boiling (for example, at internal temperature greater than 85 °C for 5 minutes or longer). Therefore, ready-to-eat foods in low oxygen-packaging are more frequently involved in cases of foodborne botulism.” https://www.who.int/news-room/fact-sheets/detail/botulism

      *For legal reasons, I have to tell you that this is for informational purposes only and not meant to be taken as medical advice. 🙂

  25. I have repackaged many side dishes like Rice a Roni, Knorr’s pasta, etc. into mylar bags and added OA’s to all. Then I read about C. botulinum concerns. All of these packaged sides come with a small pouch of seasonings, some of which I’m sure have a bit of fat and possibly moisture. I understand the parameters for the toxin being produced, but am slightly paranoid. Can you speak to this?

    • Botulism needs moisture of approximately 35% to grow. To play it safe, it’s generally recommended not to store foods with moisture content of 10% or more in oxygen-free environments. Those spice packets definitely don’t have enough moisture in them to grow botulism 🙂

  26. I used separate 5 gallon buckets for each different item. I placed 4- 500 cc oxygen absorbers in each one. All the buckets are pretty much filled to capacity and the buckets within a week started sucking in- now a couple of months later the buckets are normal again. I do not see any cracks in the buckets and the lids have remained intact. I did use snap on lids. Are the oxygen absorbers still working or did I do something wrong? Thanks:)

    • Bucket lids generally don’t provide a reliable airtight seal. Gasket lids are better, but even these can fail over time. The O-ring gets dried out and rigid and then allows air in. I know sealing them can be a pain, but it’s worth it to get some mylar bags. The seal on these is very reliable.

  27. When storing flour with the mylar and OAs, does that mean the OAs will kill Salmonella? Doing a quick search it seems the Salmonella usually found in contaminated flour can survive in aerobic and anaerobic conditions.

    Will baking the flour before storing it (in mylar bags with OA) be okay (to kill any bacteria before storage)?

    • That really overkill. Just because salmonella might be able to survive without oxygen, it doesn’t mean it will grow. The same applies to other bacteria — and there are tons of different types on all of our foods. I don’t know anyone who bakes flour before storing with OAs. Plus, salmonella is destroyed at temps of around 150F. Since you will be cooking or baking with the flour, you’d be fine.

  28. Thank you for all the information you share on here. There are SOOO many questions. LOL
    I would love to be that homesteader mother that has a rotating pantry of homegrown goods that I’ve prepped and stored but, alas, that is not realistic. However, I am concerned about being able to prep some things for an emergency situation. (I have some survival kits in storage….but those are super pricey so, I’m looking for more affordable food storage options.)
    So, here is where I am: I have several cans of Nestle dry whole milk. their 3.5lb can is only $16.xx at walmart, versus Auguson farms, etc. My question: Can I expect a 10+ year shelf life on these if I put them in mylars with OAs? I also have some individual dry milk containers that I plan to put in a mylar, as is and add an OA.
    Also: I’ve purchased some dried fruits from a local Mennonite store (again, much cheaper than online). I know not to use the OA in these but, what kinda shelf life can I expect out of these in their mylar storage?

    Again, thank you for sharing this info.

  29. When I followed your link to the gamma lid, the product description says “we do not recommend them for long term food storage or liquid applications.” Any thoughts?

    • I would consider this “lawyer speak” ie they are covering themselves in case of issues. These buckets should be fine for long-term storage. But do let us know if you find a better alternative.

    • The moisture content is fine, but dog food contains quite a bit of fat. If you poured some into a paper bag, you’d see grease stains on the bag. So, I would think it wouldn’t store more than 10 years, but if you add OAs it should last 5 years or so.

  30. I just want to thank you profusely for this comprehensive article on oxygen absorbers. Though I was familiar with this information, it took me months of combing through some pretty vague articles & posts to gain the knowledge. Your article included everything & was very much to the point.

  31. I bought 1 gal.size plastic size jars with screw on tops. I saw on a prepper site that these can be used with OAs & apply decorative Duct tape around top. I bought them to store pasta,rice & rolled oats. Is this appropriate to store this way?

    • Yes, mason jars with two-part lids can provide an airtight seal so are good to use with oxygen absorbers. The duct tape is probably overkill though. Just make sure your jars are safe from breaking. I live in an earthquake zone so none of my preps are in glass!

  32. Hi ! Hoping you can provide some guidance. Should I add (or do I need to add) food grade silica packets to foods that I am vacuum sealing? I’m vacuum sealing meals and snacks for a 5-6 month long backpacking trip to hopefully save weight/space and preserve foods for longer (than just using ziplock baggies) , but I’m not sure if adding the silica to keep any possible moisture out is needed with vacuum sealing. I am thinking about at least adding packets to store bought jerky, tortillas, dried fruit and other snacks (like crackers and cookies) before vacuum sealing them , does it make sense to do that since these items have more moisture? I am looking to keep them fresh for 4-5 months and send them to myself periodically to resupply . Thanks much!

    • Fellow backpacker here 🙂 Store-bought snacks generally don’t need silica packets. But DIY dehydrated foods (or “natural” dehydrated foods without sugar or preservatives in them) could definitely benefit from a silica packet or two! Oxygen absorbers aren’t usually necessary for backpacking foods though, unless you are super worried about nutrients degrading.


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