what-size-oxygen-absorber-to-use

Oxygen Absorbers – How Many To Use For 5-Gallon Bucket Food Storage

How many oxygen absorbers should you be using? More accurately stated… what size oxygen absorbers should you be using?

Well this short post should help you out!

When storing bulk dry foods like rice, beans, wheat, etc., a key factor for successful long term storage is to remove the oxygen from the environment. That’s what oxygen absorbers do.

Here’s why to use them, and how many to use – versus the size of the oxygen absorber you need.

 Oxygen enables bad things to happen to your food over time.

These bad things include…

– Spoilage from organisms that will grow
– Molds
– Rancidity
– Oxidation of vitamin content
– Condensation
– Bugs

The result could be bad or spoiled food at a time when you will need it the most.

 A solution to this problem is to use Oxygen Absorbers.

How Many Oxygen Absorbers For 5 Gallon Bucket

Total of 2,000 cc of Oxygen Absorber capacity.

There are several common sizes available. So, it will depend on how much air space you’re evacuating. But for the typical 5 gallon bucket with a Mylar bag insert, use 2000 cc.

I HIGHLY SUGGEST purchasing O2 absorbers INDIVIDUALLY SEALED in pack quantities you’ll likely use.

Why? Because once you open them, they ALL start absorbing oxygen. So whatever you don’t use would need to be sealed up again (vacuum sealer bag while using your kitchen vacuum sealer, or stuff them in canning jars with lid, etc..).

[ Read: Things You Can Seal With A Food Saver Vacuum Sealer Machine ]

2000 cc Oxygen Absorbers

This company sells them in various pack sizes, depending on how many you might be using in any one project.

Quantities of 5,6,10,15,18,20,25,30

2000 cc O2 Absorbers (Individually Sealed Pack of 5)
(view on amzn)

What is an oxygen absorber?

It is typically a packet consisting of powdered iron oxide. It is safe for foods, and is very effective if you have used the right amount in a sealed environment.

Earth’s air contains 21% oxygen. The proper quantity of oxygen absorbers in a sealed Mylar bag, or a sealed pail or can, will reduce the oxygen levels to .01%, effectively eliminating (minimizing) the risk of bad things happening to your food storage.

There is a caveat to effectiveness however. The container MUST be air-tight. Most people use Mylar bags to fit in their 5-gallon buckets.

Use With Mylar Bags

The Mylar foil will provide an air-tight seal if sealed properly, and the bucket will provide protection for puncture or rodents.

[ Read: How To Seal a Mylar Bag in a 5-gallon Bucket ]

NOTE: You should check your new Mylar bags for leaks. Use a flashlight shining inside the bag in a dark room and look for any light escaping. Some may have small holes at a folded crease.

They’re Shipped in a Sealed Bag

Oxygen absorbers themselves are shipped in a sealed bag or packets. So, remember, once you open that sealed bag, the absorbers will start absorbing the oxygen of the air around it. So don’t leave them sitting around for long (try to keep it under 30 minutes) while they are ‘absorbing’ the oxygen in the room.

Have your food ready and already packed in the Mylar bags, ready to seal, before you open up the pack of oxygen absorbers.

Then, use what you need and save the rest in an air-tight container. You could use a vacuum sealer bag for the remaining O2 absorbers (probably the best way), or you might keep them in a canning jar with an air-tight lid (fill the remaining air space inside with rice which may help reduce the volume of O2 inside).

Oxygen Absorbers are rated in cc (cubic centimeters)

The sizes of oxygen absorbers correspond to the amount of oxygen they absorb.

For example, a 300 cc oxygen absorber will absorb 300 cc’s of oxygen.

So the key to knowing how big of an oxygen absorber to use, is to know how much total air (oxygen) it will need to absorb…

…which is the ‘head space’ air plus the air that’s all around the individual pieces of food inside the Mylar bag or bucket, called void space.

What matters is the is the air volume in the container after you have filled it.

To determine the total residual air that will remain in your storage container (sealed Mylar bag), you could apply a moderately complicated procedure and formula, or you could follow some general advice based on other people’s experiences and others who have run the formula as follows…

2000 cc For 5 Gallon Bucket

For foods like rice, beans, or wheat berries stored in a Mylar bag to be contained within a 5 gallon bucket, use 2000 cc’s of oxygen absorbers. This leaves a bit of a safety margin which is particularly important for larger size items such as beans because they have a bigger void space around them.

Given the value of your investment, it’s worth adding a bit more oxygen absorbers than necessary. While 2000 cc’s is enough (for a typical 5-gallon pail with Mylar bag filled with rice or wheat, etc.), 2500 or even 3000 cc’s will absolutely assure best results. It’s up to you.

What Size Oxygen Absorbers for Pint, Quart, Gallon

The following guideline is for dry goods such as cereal, oatmeal, oats, wheat berries, barley, corn, rice, etc..

Pint = 100 cc
Quart = 150 cc
Gallon = 500 cc

[ Read: Diatomaceous Earth For Long Term Dry Food Storage 5-Gallon Buckets ]

[ Read: How To Install Gamma Seal Lids For 5-Gallon Bucket Easy Access ]

51 Comments

  1. I buy my grains directly from the farmers. Using a moisture meter,I find the moisture content to be about 13%. This is to high for long term storage.

    I place the grain in aluminum trays in the oven at 175 degrees for 8 to 10 hours. The moisture level is then reduced to about 7-8%, which is suitable for long term storage. This level is needed to prevent Ergot and other fungus growth.

    Ergot is a fungus that grows on many grains, even at reduced oxygen levels as found with the use of oxygen absorbers. Nausea, seizures, and hallucinations are among the symptoms of Ergot poisoning.

    Also note, that grain that I purchased from some suppliers of grain for “long term storage” have tested excessively high for moisture content. A moisture meter is not that much of a one time expense in comparison to the cost of the grain.

    1. It may or may not matter to you depending on the grain and how you intend to use it but a prolonged exposure to that high temperature could break down the enzymes present in the grain. This could impact the grains performance when making bread.

      1. Also Hight Temperature drying makes PLANTING it for seed a problem. Time is coming when your stored wheat and beans will run out and seed is needed.

        Research how to dry seeds friends. It’s not that hard given they did it during Bible Times and seeds found then are still viable today.

  2. That I did not know (moisture level). I will go out and purchase a meter. Thanks for the info.
    Dario

  3. Note that even Mylar bags will very very slowly over time allow some moisture and oxygen to permeate through the Mylar and aluminum coating. (I have personally seen water vapor permeate sealed die cast aluminum electronic control module enclosures that were hermetically sealed, and we even measured permeation and accululation inside when the enclosure was internally pressurized!). So, my engineering experience suggests include more or larger absorbers than volumes alone would necessitate to accommodate this ingress over long durations.

    One tiny technical thing, the absorbers contain powdered iron which then eventually turns into iron oxide as it “absorbs” the oxygen by binding the oxygen in the iron oxide. It is a slow process but produces a very strong bond releasing heat, enough that the same chemical process is used for those small chemical hand warmers.

    1. As long as it is Grade, it should not harm the beans, etc.
      Many people Mix Food Grade in water or other liquids & drink daily.

      But when spreading this around, you should wear a mask or hold a cloth over your nose & mouth. Isn’t good to Breathe it in.

      You can search online for more information.

      I’ve ordered some which I will spread around the outside of the house & around an outside storage. Food Grade is safe for humans & pets (just don’t breathe it in while spreading)

    2. Yep–I just sprinkled a little on the bottom, in middle, and on top. It is edible –if livestock are given it often to prevent parasites, why not use it for parasites in buckets?

      I bet you eat worse in that morning cereal–I do.

  4. I use chemical disposable hand warmer packs. They are cheap at the dollar store and they eat a large volume of oxygen.

  5. Greetings all,
    Has anybody measured how much Oxygen a handwarmer actually absorbs? Or can anybody point to anything online touching on this aspect? I’m happy to repurpose an item — once I’ve satisfied myself that it’s safe and will do the job.

    If I make a measurement (or even an estimate), I’ll post that.

    I’m similarly wondering about quantifying the air leakage rate of some 5-gallon buckets, since the leakage rate will likely dominate how much oxy will need to be scavenged for long-term storage.

    Thoughts?

    1. I use recycled grade buckets with gaskets that I get free from the bakery departments at the supermarkets.

    2. c4talyst, i just saw this question. Thought others might not know as well.
      i use 2 hot hands per 5 ga food grade bucket. and seal well. gamma lid preferred, rubber gasket a second best,then seal with gorilla type tape going round several times.

  6. IS it advisable to place rice, beans, etc. in the freezer for a few days to kill off any bugs or eggs? Also, if that is done, when removing that from the freezer does that present some sort of a problem with condensation>
    Is there a paarticular way to do this ?

    1. I use the freezer method for my flour and rice ( one week)….note the part of the country you live in is the biggest factor, now live in northern nevada, about 15 % average humidity therefore absorbers and other elements are not a factor. 15 years of trial and error while living in this state, I have had no long term storage failures by not using either vacuum seal or absorbers unlike living in Tenn or Texas where humidity and bugs was always a concern. Ironically it has been a blessing after spending decades of gaining food storage knowledge to combat food degradation coupled with critter infestation. In nevada my only concern regarding food storage is high temps. So I order any bulk food items online and during the cooler months of the year. Living 100 miles from a Wally World and city’s makes shipping bulk food items to the casa, a godsend.

  7. If you put the food (rice) in the freezer to kill any potential bugs prior to putting in the bucket for long term storage, then you need to let it sit out to dry any condensation, how do you know it doesn’t get infected again by moths?

    1. Inquiring & New,
      I rotate my dry goods thru the freezer from 3-14 days- depending on how rushed or busy i am in other areas./OR pressed for freezer space.I let them sit out enough time to return to room temp.(24-36 hrs). If putting into food grade bucket w/o Mylar i add bay leaves to the middle and top.( 3-4 over a layer of rice.).. once the bucket is open they will repel bugs..
      If you seal rice/dry goods with an oxygen absorber the larvae can not live, will/should be microscopic when purchased. Rice should be washed well in strainer… and soaked for at least 30 min. that water should be thrown away… add fresh water for cooking and if soaked and swelled will need minimal cooking time. 5-8 min simmering covered. and 5 minutes to steam..
      You can also store them in Cola bottles if you run out of buckets.(ga. jug holds abt 8 #: 3 liter abt 6# . wash bottles hot soapy water/rinse well. I use vinegar rinse. turn top down, and put a rolled paper towel n top/to wick moisture … takes about 2-3 days to get them real dry.. shake down well when filling.. drop in oxygen absorber. put lid on tightly, put pc of tape across top signifying is sealed.I like to lay them on their side and pat them, the bottles will suck in with two flatter sides.making storage easier.Be sure to label kinds. I put recipes/instructions on side of some of containers. Food grade buckets and Gamma seal buckets do away with the need for mylar.bec Gamma seal lids have 2 rubber gaskets, seal tightly, easy to open. Self rising flour will NOT rise well 6 -9 months past the date on it.
      i have begun putting a zip lock doubled each of salt, sugar, cream of tartar and box of baking soda in with each 5 ga bucket of plain flour.for compete baking needs, having vinegar and oil,, will complete many pantry stretchers.

      1. Thank you. I learned a lot from your reply. New to this. I like your pop bottle idea also.

        1. Coke, or water bottles, I use 1/2 gallon ammonia bottles that have been washed and dried out, also 1/2 gallon fruit juice bottles……the key is using smaller containers allows for individual use age thereby letting the rest to be stored without continuous usage and if used for helping others you can easily regulate distribution.

      2. Do most regular grade grade bucks allow air in? I still need O2 absorbers. I don’t have Gamma lids or extra gaskets and hoping I don’t need them.

        1. Lise-Anne
          It will depend on where you picked up your buckets at. Most of us have been able to acquire them from large grocery stores that once had major bakeries. Those places did not need nor want to keep them, so we asked, and they were kind enough to give them to us. It saved on them with the cost of disposing of those buckets.
          Some places have stopped that process so you will have to check around the area where you reside.
          Make sure IF you acquire the buckets that you asked for the lids along with them, as they do not always provide the lids unless you request them. One place in particular is Cost co, they used to give you the small buckets but no lids. Reason I happen to mention this to you, so you know their guidelines.
          Should you be provided the lids make sure the rubber gasket is on there so that you have a tight seal.

  8. FYI.
    I wanted to see how the following test would work for grain storage.

    Well, a few days ago I opened the 55 gallon test drum where I stored 100 lbs. of white rice for 5 years to see the out come. The test drum was about half full of rice when I started. Before sealing the drum with the lid, I placed a coffee can full of burning charcoal on top of the rice to burn up the oxygen inside the drum. I put a brick under the coffee can not to burn the rice. I put about a pound of salt in the drum to absorb any mosture produced in the drum by burning charcoal, etc. After sealing the drum with the lid, the drum got very hot, too much charcoal but it did not melt the drum or lid. As the charcoal began to burn up the oxygen the combustion began to produce carbon monoxide, killing any bugs. Carbon monoxide would kill you also.
    Results: the coffee can was a pile of rust. The rice is still good, I have eaten some. After sifting the rice there were a few dead bugs, they had not eaten any of the rice grains that I could see.

  9. I called Pack Fresh and they will seal individual oxys for you. I had to purchase a certain amount, but the individual packs have been nice to have. On the ten packs I get my vacuum sealer out and immediately repackage what I did not use. Label the amount left over. Putting in a jar did not work for me.

  10. For everything but the large buckets of grain I use 500cc and a 7 mil quart bag. I found it easier than trying to decide if this food needs a pint or quart and which oxy would be best. This way I know it will work and do the job.

  11. Anybody know how long a bag of whole wheat flour, sealed in Mylar with an O2 absorber, would last?

    1. Chipmunk
      Purchased Bob’s Red Mill around 2012 or maybe 2013, split the bag with my sister. I am still opening up the bags from that time frame as we do not go through flour that quickly. Mostly use it in the winter time for making ACDH cookies. In warmer months I purchase pre-made cookies rather than warm up the house.

      1. AC, when I read walmart demanded masks, I got 5 bags of White Lily, the only flour that makes decent biscuits, and vacuum sealed in pint jars for long shelf life.I had in freezer, but needed space when bought a lot of ground beef @ 2.10 a lb.

  12. I have an Aunt who’s a major gossip. I just invite her over whenever I need oxygen absorbed in a room.

  13. I have a suggestion. It’s great that people are trying to help each other. With food issues I recommend reading food safety (storage, handling, etc.) textbooks, books on HACCP training (mainly for restaurants but the one I have has good info on spoilage, bacteria growth, etc.) Find experts to contact.

  14. For those without a moisture meter:
    Taken from the LDS Preparedness Manual by the Latter Day Saints, a very wise and prepared group with the notable exception of Mittens, crush a wheat grain and if it’s dry ( not powder ) inside you have achieved a level to go forward with packaging the wheat.
    I obtain this level using lasagna pans in a 160 degree oven for 1 hour and occasionally stirring.
    The grain is not likely to be viable for planting.
    It is better to preserve seeds for planting using a different method. Be mindful that the germination rate falls greatly for saved seed beyond the next planting season.

  15. Hi I don’t know if I used the right amount of oxygen absorbers. I have 5 gallon Mylar bags of white rice sealed and in put them in 5 gallon food grade buckets. The air did not come out of 6 out of 8 of the rice Mylar bag buckets. I used 1500 cc or 3 500cc oxygen absorbers. Do I need to cut a slit in the bag and add another absorber to make it 2000cc or will this damage the others already in the bag because I’m letting oxygen in the bag.

    1. Eliana, Oxygen absorbers do not create a vacuum in the bag. They remove and fix only oxygen, which is 21% of the air. 78% is nitrogen and will remain in the bag. If you want a vacuum in the bags use a vacuum sealer, as well as the O2 absorbers.

  16. I recently bought 10llb bags of pancake mix. It takes 3 bags to fill them bucket leaving room for ironing the bag. Put them in a mylar bag in a 5 gallon bucket with a gamma lid. Putting a 3000cc oxygen absorber in it with a bay leaf in top then iron the bag. You can also run a light bead of silicone around the top and can be cut when opened, will also prevent slippage of the lid

  17. I just purchased a 25lb bag of whole white wheat berries and I have a 3.5 gallon bucket to store them in. How many 400cc oxygen absorbers would I need?

  18. my experience is that if enough CCs are used the mylar bag will look vacuumed sealed, almost like some kinds of packaged coffee. is that overkill? can a 2000cc O2 absorber remove all the O2 without the bag looking vacuum sealed?

    1. To fastimes,

      In my experience, it depends how much air that you’re able to remove (or squish out / flatten the top of bag) prior to sealing /ironing with the O2 absorber inside. I’ve had some 5-galloon bucket Mylar bags suck in real tight, while others not as much. I do use 2000 cc for 5-gallon buckets.

  19. fasttimes, Oxygen makes up 21% of the air. So oxygen absorbers will only remove a maximum of 21% of the air in a sealed bag or container. If very little air is in there to start with the bag might crumple a bit. If you want all the air out, use a vacuum sealer.

  20. I’m storing 6- 5 lb bags of flour in a 5 gal food grade bucket with a food grade bucket liner. How many 300 cc oxygen absorbers do I need? Do I also need to vaccum seal the bag?

    1. Linda lou
      It will depend on how you are packaging up the flour.
      If you are doing each bag separately (wise move), you will need one 300 cc per bag. Then when the flour is in the bags and have the oxygen absorbers included you will run an iron or a curling iron across the top to seal the bag.
      Make sure you seal it with a small section left open so that you can squeeze the air inside out of the bag then finish sealing with your iron. Mark the date you put up the flour, so you use the oldest first.

      I would like to recommend that you look for wheat berries. What are these? They are berries the make your flour. You will find them in soft wheat/hard wheat and rye.
      Do more research on which you or your family will consume. Then my suggestion is for you to pick these up and process them the same way you would your flour. One last item you will need a wheat grinder for making the flour. The wheat grinders come in electric and hand grind-fyi.

    2. Lindy lou,
      Note self rising flour does not keep as long as all purpose/plain flour. I have used it about 9-10 months past the date on it and it performed ok. It will go rancid eventually. been long enough i do not remember how long that was.
      I used to cook exclusively with SR flour, moved where it was not available 14 years ago- DH became the cook for flour based items(if he wanted to eat them) Yes, I chickened out! finally go to point i can make an ok biscuit.pancakes.etc.,
      Beyond that it looses it ‘s “rise.” For a time, it can be extended with cream of tartar added/ but do not add soda or salt to self rising flour.
      I can not give you time AP flour will last, not had any that long. pack it as well and secure as you can. wheat is getting harder to get by the month. saw a comment on a page yesterday. rice crop in Arkansas is down by half, according to one who works processing and recieving grain.

  21. Is a 200 cc absorber enough for a 5 lb bag of grits, flour or cornmeal each in their own mylar bag, & then storing 4 bags per bucket? So glad I found info on amounts here but haven’t seen anything about any number of pound cc’s required. Thx!

  22. Susan,
    Found this info at True Leaf Market

    #10 Can
    Flour, sugar, powdered milk & similar: Use 200 to 300 CC
    Wheat, rice, grains, seeds & similar: Use 200 to 300 CC
    Beans, large seeds, pasta & similar: Use 300 to 500 CC
    5 Gallon Bucket
    Flour, sugar, powdered milk & similar: Use 700 to 800 CC
    Wheat, rice, grains, seeds & similar: Use 800 to 900 CC
    Beans, large seeds, pasta & similar: Use 1000 to 1200 CC

    Hope this helps

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