Flour is considered a non-perishable food. However, if you don’t store flour properly, it will go bad. Here’s what you need to know about flour storage and the best options, including for long-term storage.
How to Store Flour Long-Term
In its original paper bag, flour won’t last more than 6 months. If you move it to an air-tight container, it can last 6 – 10 months. For long-term storage(over 3 months), the best method is Mylar bags with oxygen absorbers.
Why Flour Goes Bad
Just like any dry food, flour can go bad if it is exposed to oxygen, light, moisture, or insects. If you just leave a bag of flour in your pantry, here are some of the problems which can occur that will make the flour go bad.
Mold: Humidity or temperature fluctuations can cause flour to absorb moisture and eventually start to get moldy. You’ll be able to smell the mold before you actually see it.
Oxidation: Oxidation occurs when oxygen from the air interacts with nutrients in the flour, causing them to break down. This is particularly a problem with whole-grain flours. Oxidation will cause the natural oils in the whole-grains to go rancid.
Insects: Even if you store your flour in air-tight containers, you can still get insects like weevils or moths.
How is that possible?
Because flour often already has insect eggs in it when you buy it. It can take weeks or months for them to hatch depending on the conditions. Once they do hatch though, you have an infestation which is very hard to get rid of.
Absorbing Smells: Flour can act like a sponge and absorb the smells of whatever is near it. Have onions next to your flour? Then the cake you make with it will have an oniony smell too. You especially don’t’ want to store flour (or any other food, for that matter!) near chemicals like cleaning products.
Best Ways to Store Flour
Below are several flour storage methods. If you want to store flour long-term (over 3 months), then the best method is Mylar bags with oxygen absorbers. No other method is truly reliable for long-term flour storage.
Shelf Life: Approximately 6-10 months
In its original paper package, flour usually won’t last more than 6 months. If you remove it from the package and put it into an air-tight container, it can last much longer.
One potential problem is that there might already be insect eggs in the flour when you get it. It can take weeks or even months for the eggs to hatch. When they do, you will have a nasty infestation which is hard to get rid of. Thus it’s smart to take steps to kill insect eggs in the flour before storage, such as by freezing or microwaving it first.
Some good flour storage containers include:
- Mason jars
- Vacuum sealer containers
- Air-tight containers like those made by Progressive Prepworks or Rubbermaid’s Brilliance
Shelf Life: Indefinitely
If you have room in your freezer, freezing flour is a great way to store it. It will last forever in the freezer, though you should have a plan in case power outages occur.
To use, remove flour from the freezer and let it get to room temperature. Note that flour can absorb moisture due to condensation while you bring it to room temperature. To prevent moist flour, keep the flour in its sealed container – the condensation will collect on the container instead of getting into the flour.
Drying Damp Flour:
If the flour gets damp, you can spread it out on a baking sheet and heat it in the oven at about 200F. If the flour is very damp, you might need to heat for up to an hour to get it dry. After drying it, sift it to remove any clumps.
Shelf Life: 1-2 years
The vacuum sealing process removes air from the packaging. The bags are not completely leak-proof; air and humidity will eventually seep through. However, the reduced amount of air means flour stored this way will last much longer.
Vacuum sealing also keeps insects from getting into your flour. It will NOT kill insect eggs which are already in the flour though. That’s why many people first take steps to kill insects in dry food before storage.
To store flour with vacuum sealing:
- Place the entire bag of flour into a large vacuum sealer bag. You cannot dump the flour directly into the vacuum sealer bag because the particles of flour will get sucked into the machine.
- Follow your products instructions to vacuum seal the flour.
- Put the sealed flour in the freezer for at least 96 hours. This is to kill any insect eggs which are in the flour.
- If you must remove the flour from the freezer but won’t be using it right away, let it come to room temperature before putting it in any other storage container. Otherwise condensation will form.
Buckets, Plastic Containers or Jars with Oxygen Absorbers
Shelf Life: 5+ years
Oxygen absorbers are little packets of iron which trap oxygen. If you place OA packets into a food-grade plastic container with flour, it will absorb the oxygen in the container and prevent spoilage from oxygenation. The lack of oxygen also means that insect eggs can’t hatch.
The problem is that most storage containers are not truly air-tight and will eventually leak. This includes recycled soda bottles as well as food buckets.
Buckets with gasket lids (see on Amazon) are usually better at preventing air leakage, so are a decent option if you need to store a large amount of flour.
Canning jars also tend to be very reliable and you’ll know the oxygen absorbers have worked because the lid will look “sucked down.” Just be careful to store jars somewhere cool and dark, as heat and light can also cause spoilage.
Read about oxygen absorbers here.
Mylar Bags with Oxygen Absorbers
Shelf Life: 10+ years
If you want to store flour for months, years, or even decades, the best solution is to use oxygen absorbers in sealed Mylar bags.
Mylar bags are made from a metal-like material which is impervious to moisture and oxygen. By sealing flour in Mylar bags with oxygen absorbers, the flour is completely safe from light, moisture and oxygen. Even insect eggs can’t hatch because there isn’t oxygen in the packaging.
When stored this way, white flour can last 10-15 years. Whole-wheat flour can last approximately 10 years this way.
Read about how to store food in Mylar bags.
Dry Canning – Not Recommended
Dry canning is a process where dry foods like flour are put into canning jars with lids and then heated in the oven. The heat is thought to sterilize the food and create a seal. Even though canning jars are used, dry canning is NOT the same as water bath canning.
As warned about by NM State University, there are a lot of potential problems with dry canning.
- There’s no evidence that the process actually sterilizes food
- The process can trap moisture in the jar.
- Botulism poisoning could occur if moist food is sealed in an oxygen-less container. This is not an issue with foods that have less than 10% moisture content like flour, but condensation trapped in the jar could mean the flour does get very wet.
- Jars can sometimes EXPLODE
Because of these issues, Mylar bags with oxygen absorbers are the only acceptable method for storing flour long-term.
Leave a comment
So I put my flour in a big trash bag and froze it for about a week. Then I let it sit out on the counter to come back to room temperature. After than I placed the flour in brown paper bags. Taped them shut. Then vacuum sealed those. I did throw in an oxygen absorber between the brown paper sack and the plastic bag. Not sure if I should have put it in the flour. But it sealed everything well and I have a pound of flour vacuum sealed in each bag. Could you guess that would lengthen the time more than 2 years?
Your flour should last quite a long time like that. 🙂 Obviously I can’t say exactly how long it will last because some things – like if you live somewhere very hot and humid — will decrease shelf life. You should really look into Mylar bags + OAs though. I find it to be less work than dealing with freezing staples, but that’s just my opinion.
Vacuum sealer bags are not made for use with oxygen absorbers- they will absorb oxygen.. I put mine in the vacuum sealer bags Then into Mylar with O2 absorbers- will last 15 years. Your method however should be good for about 2-5 years.
You say, “they will absorb oxygen..” do you mean the Vacuum Sealer Bags? Or the OA bags? Thank you
The OA will absorb oxygen through the vaccuum sealer bag. Anything will eventually absorb oxygen through the vaccuum bag because they are air-permeable at a molecular level. The rate of oxygen transmission is very, very low but when you are looking at years or up to a decade, it becomes significant.
Can you leave the flour in the bags they came in and seal in mylar bags?
No. Best to remove the factory packaging and place into a mylar bag. Vacuum seal if you can.
I keep my flour in the original bags, open a small slit in the bags to insert oxygen absorbers and remove excess air, then seal in mylar with additional O2 absorbers.
Steve, I don’t understand why you say no to original packaging. If the ultimate mylar is well sealed with adequate O2 absorbers it should work?
Dee, your method should work wonderfully. The original packaging is only a problem if it stops the OAs from doing their job.
Hey, what are OA´s (sorry!!) and also if you seal flour in the Mylar bags and then need to access the flour isn´t the seal broken and do you then take what you need in the short term and then reseal the same bag? Thanks so much x
OA is Oxygen absorbers, Yes if you open the bag the seal is broken. Take what you need out and get new oxygen absorbers to reseal the same way. If I open a mylar I use what is inside and replace with new products. Just wash gently the mylar and make sure it is dry dry dry before using it again.
What about buckets with OA’s? I have heard that oxygen permeates through the bucket walls (even with the gamma lids on). But I can fit a lot more in a bucket than I can with Mylar bags in the bucket. Lots of wasted space that way. 🙁
The issue is more that the bucket lids will eventually start to leak. The gaskets are made out of a rubbery plastic material and it gets brittle, thus allowing oxygen to leak inside. Maybe some air leaks through the bucket itself, but I doubt it. However, air DOES leak through vacuum sealer bags, water bottles, recycled plastic bottles…
Trash bags are NOT food grade plastic. Please nobody else try this.
It sounds like the above poster kept the flour in its original packaging, then wrapped it in the trash bag while it was in the freezer. Upon removing it from the freezer and thawing (before repackaging), any condensation that formed was on the trash bag, which was then removed and discarded. It kept the moisture off of the original paper packaging. The food and trash bag never touched each other.
I believe you’re correct
Doesn’t matter what touched the flour. It should be removed from the plastic bag and paper bag and vacuum seal in a mylar bag.
Do you think, Vacuum packing 1st than freezing and than returning to a normal temperature will kill the eggs? Thank you
Check over the whole article again:
Freezing in (food-grade) plastic bags, then thawing before removal, should kill any eggs or microbial contamination, for the same reason freezing meat will help prevent spoilage; the moisture in the microbes or eggs will turn to ice crystals, destroying their internal structure.
The Mormons can flour straight from 50 lb bags. They use the large #9 cans and place an oxygen pack inside. They say the life expectancy is 5-10 years if placed in constant temperature about 72deg I thing…. No freezing no baking only an oxygen absorber…
My experience with canned flour from one of the “Mormon” canneries has been very positive. I was able to use my flour storage for almost 9 years. Then I noticed a newly opened can didn’t taste or smell quite right – the flour had taken on the taste of the can. I discarded the two last cans, but I think 9 years in storage is amazing!
Wow… Flour would last that long on just the shelf. Vacuum bags don’t deal flour well and it most likely will loose it’s seal in a few months.
I would guess it will last about 5 years. Flour is always safe to eat even if it develops a yellow tint or an odd smell… If life gets tuff and you need to eat.
This is recommended if your storing food for disaster prepping. If your trying to save money and buying in bulk then the rule is 5 years or when you don’t like the smell or color
Can I put the flower in the microwave and how long before I put it in a Mylar bag
What about non -wheat flours? Do they have the insect egg problem too?
Yes they do! Almost any grain will or can have insect eggs. However, I personally haven’t noticed the problem with cornmeal/polenta as much. It might be because that is usually packaged in plastic whereas many other flours are in paper bags which can easily be penetrated by insects.
I find that cornmeal or polenta can have moth eggs.
If I purchased Augason Farms white rice and All Purpose Flour in the large pails, do I need to freeze the pails, or did Augason Farms do it prior to placing the rice and flour in the pail?
I’m not sure if Augason treats their products before putting them in buckets. However, I’ve asked around and no one seems to have had any issues with bugs in their products. The safest thing to do would be repackage the flour/rice in Mylar bags with OAs (you don’t need to freeze when using OAs; bugs can’t hatch without oxygen). you could freeze it, but it would be a pain to freeze that much rice and flour!
Auguson puts OA’s in their containers, so they are already packaged for long term storage.
This information was extremely helpful for beginners. Thanks
I like your site. Good content. Not to wordy. Friendly yet concise. Ty.
Why thank you 😀
i agree we like your no nonsense style. excellent content and easy to access, knowlegeable and brief. the most helpful format i think everyone is scrambling and don’t want to waste a lot of time. IMHO. Thanks look forward to more.
Thank you! <3
I use the 2000-2500cc oxygen absorbers for 5 gallon. What I would like to know is if I freeze flour in the original packaging and thaw it out and package just the flour in a mylar bag with an OA should I be adding a moisture absorber to decrease botulism from forming?
There is no reason to freeze the flour first if you are using OAs. Insects and their eggs can’t survive without oxygen.
I put my flour in ziploc bags with oxygen absorbers in each bag, I plan to put the bags in a 5 gallon bucket, the ziploc bags are not full, how do I know if the oxygen absorbers are working?
Ziploc bags actually aren’t completely airtight. Air leaks in through the seal and through tiny holes in the plastic bag itself. After putting an oxygen absorber into them, the bag might look “sucked down” a bit. But, over time, the air will leak bag into the bag. I know sealing them can seem intimidating, but Mylar bags + oxygen absorbers really are the best way to go for long-term storage of dry goods.
Will self rising flour last as long as all purpose being vacuum sealed?
It will last just as long — but it might not be “self rising” anymore. That’s because the baking soda and/or baking powder that is in self-rising flour can lose its potency after a while in storage.
Can you store cornmeal bolted white with absorber in mylar and how long can it last and after sealing it I am not sure if it should be hard or soft and I don’t think it will be like rice that tighten? I stored white flour for two days in freezer that is what most said should I start over?
We talk a bit about cornmeal in this post: https://www.primalsurvivor.net/mylar-bags-food-storage/. For whatever reason, cornmeal doesn’t get “sucked down” in Mylar bags with OAs like a lot of other foods. As for the flour in the freezer: it doesn’t need to go in the freezer before putting in Mylar bags with oxygen absorbers. If you are storing it without oxygen absorbers though, such as in a vacuum sealed bag or plastic containers, then it needs to go in the freezer to kill pests. More on that here: https://www.primalsurvivor.net/bugs-weevils-moths-food-storage/
We have just done a full post on the long-term storage of cornmeal.
Ok, I have my flour in the freezer at the moment. I plan on taking it out and baking it a bit. Sealing in 5 gallon Mylar bags with oxygen absorbers. Then I’m placing in a drum with a gasket seal. I was wondering if you have heard about Damascus earth? I bought some cause I read a article somewhere about it but now cant find it? Also if the flour won’t rise can I add something to make it. Thanks for all the info.
You don’t need to do the freezing step if you are using oxygen absorbers. Those will keep insect eggs from hatching. Just keep that in mind for the next batch.
As for flour rising, are you talking about self-rising flour? Self-rising flour just has leaveners like baking powder added to it. Just follow recipes which don’t use self-rising flour. They will call for baking powder or baking soda.
I’ve had 20 lb of white flour, in original 10# store bags, in my freezer for a couple months because I wasn’t sure how I was going to store it. I’m using all our freezers more now and need the space. I have Mylar bags and OAs and now plan to put it into them. So, I can just let them out, maybe for a day, then seal them in those bags? I’m concerned now about condensation forming. Is there another step to take when I move them to my kitchen to thaw, before sealing? Thank you!
Ideally you would spread the flour out a bit while thawing, to make sure any moisture pockets are gone. Also, if you live somewhere humid (like Florida), make sure you have a dehumidifier or AC going when packaging.
When placing 5 lb bags of flour in mylar bags with OAs, do I have to remove it from the original packing?
You don’t have to. However, if you don’t remove the flour from the original packaging, it won’t fit well in the bag. You’ll end up with lots of extra space in the bag and need to use a lot more oxygen absorbers.
But, I think if you vacuum seal it first it may fit in 1 gal mylar bags. Haven’t tried it yet though.
I stored my flour in a 5 gallon food grade bucket with a 2000cc OA. I didn’t use mylar bags when I stored it in the bucket. My lid has a seal. Is this sufficient enough? Or do I need to open my buckets and restore in the mylar bags? Any help will be appreciated.
That’s probably fine, especially if you will rotate through the flour eventually. The issue is if you want to store the flour for 5+ years. In my experience, the o-ring on bucket lids eventually dry out and warp, so they are no longer air-tight (and thus the OAs won’t be doing their job anymore). This means that the flour will slowly start going bad. Now, WHITE flour will last a really long time even without any special storage. It will be fine in a bucket with or without OAs. But whole-grain flours really need to be protected against oxygen.
The bigger issue is that INSECT EGGS may be in the flour. Insect eggs won’t hatch if there is no oxygen. But, if the OAs aren’t working because the bucket lid leaks, those eggs could start hatching and you would get an infestation! I’ve gotten used to eating food with pantry moths and weevils in it! 😀 If you leave it in the bucket, just be careful when you open it – you don’t want to release a zillion moths into your home.
The 5lb bags of flour fit perfectly in 1 gallon mylar with enough space to add O² absorbers, squeeze excess air out, and seal.
So is there any reason to take the flour out of the paper bag it comes in if I was going to do the following..
1) freeze out the critters first
2) bring to room temp
3) slide entire flour bag into a mylar bag, toss in the oyxgen absorber
4) suck out as much air as possible with food saver attachment and then seal
5) put Mylar bag into 5-gallon pal
What I’m looking for is any reason to bother taking the flour out of the original packaging? Leaving it in seems like it will make things a bit easier on the other end.
You don’t need to bother with freezing the flour if you are packaging it with oxygen absorbers: the critters and their eggs can’t survive without oxygen. You could keep the flour in the original bag. But it won’t fit very well in the Mylar bag: you’ll end up with lots of extra space on the sides of the bag, which means you’d have to use lots more oxygen absorbers to remove that air. So, in theory, you could leave the flour in the bags — I just don’t recommend it. 🙂
Personally, I would freeze anyway, because if the objective is long-term storage (over 1 year), the oxygen absorbers will help abate microbial spoilage; mold spores are not like bacteria, and will not necessarily be eradicated by freezing, but their growth will be abated by deprivation of both oxygen and air moisture.
Snip the bag at top side so you suck the oxygen out of the bag too and you will be fine.
Does brown rice have botulism if stored with oxygen absorbers. Can it be used to feed dogs safely. Should it just be thrown out. Was put in mylar bags with oxygen absorbers in 2014. What about whole wheat flour also.
Botulism isn’t the issue with whole grains. Rather, it’s the healthy fats in them. They start to go rancid quickly (usually about 2 years shelf life). This post has more info: https://www.primalsurvivor.net/mylar-bags-food-storage/ and this one too https://www.primalsurvivor.net/oxygen-absorbers/
Thanks for your post!
I store my flour in food safe buckets with bay leaves thrown into the bucket. Bay leaves will kill bugs.
Would 1 bay leaf be enough per bucket?
what about putting a piece of dry ice in the bucket and let the dry ice evaporate forcing the oxygen out? let the lid set on top but not sealed.
Your thoughts please.
I don’t know enough about this to give an expert opinion. It seems like there is a high likelihood of mistakes though. I personally prefer Mylar bags + O2 absorbers; I can easily check whether the bags is sealed well and, when using O2 absorbers from a reputable company, feel secure that the flour is safe for years.
Great article with great content! I’ll have to save this site under my favorites. Great information for anyone looking to store things long term.
Is it ok to put OAs directly into the flour. Say one inthe middle of flour and one on top? Or just put OAs on top always?
It really doesn’t matter. Mine always go on top though because I try to work fast: I fill the Mylar bags with flour, give them a nice shake to settle the flour, and make sure everything is set up. Only then do I get out the OAs — which means they end up on top.
Same as previously said, good info and thanks for being concise. I hate recipes where the author gives her life story before you can find the ingredients.
Question: Flour, cornmeal and other dry goods. Can I put them in mason jars and seal with vacuum? ( food saver). I do beans and rice this way and others say good for “ up to 20years”. Regina
Yes, that generally works. The only main issue is that there might already be insect eggs in the grains/dry goods BEFORE you put them in there. They can take 6 weeks or so to hatch, meaning you end up with an infestation in the jar. I talk all about that (and how to prevent it) here https://www.primalsurvivor.net/bugs-weevils-moths-food-storage/
Is this book available in hardcopy? All that I see indicates it is only available as an Ebook.
Our books are only in e-format now. The exception is Disaster Preparedness for Women, which you can get as a hardcopy on Amazon
Just ordered :)))
When using Mylar bags with o2 absorbers with flour, will the bag “suck in” as it does with other foods?
It’s weird. Sometimes it will suck in and other times it won’t. It has to do with the nitrogen content of the food and closed package. Nitrogen is another gas found in air. Oxygen absorbers only remove oxygen, not the nitrogen, so the O2 can be completely removed without the bag getting sucked in like with vacuum sealing.
Being gluten-intolerant, I would like to store gf flour, but gf flour often uses some brown rice flour in the mix. I’ve read that brown rice does not store well. Does that include brown rice flour? I’m prepared to seal with food saver; place in mylar bag & then into a bucket using high amounts of oxygen absorbers.
You read correctly. There is a lot of fatty oils in the bran part of brown rice. It’s in the flour too, so will start to go rancid eventually (it should still be fine for years but it’s impossible to get an exact time — heat will make it go bad much faster!).
I personally would just make my own GF flour mixture using white rice flour and other processed grains. These last a very long time when stored with OAs. I know it’s not the healthiest option but it is safest for long-term storage.
Love how to the point you are without wasting a lot of words. One thing about YouTube videos is they talk to much. They take 20 min to tell a 5 min story.
One last thought in the event of a system crash because they are just printing money could one not let some bugs get into the product as protein? Lol
yes, you could eat the bugs, but the bugs are getting their protein from the grain product. so it is more efficient and less icky (and less bug poo) to eat the grain, not letting the bugs eat it. if the bugs are already there, then go ahead and eat them if you want. bake your bread and eat with your eyes closed. Lol
I blend things which have insects in them so I can’t see them (like making awesome pasta sauce from blended pinto beans and tomato sauce). If I can’t see the bugs, it doesn’t gross me out. Ideally the bug-infested product should be cooked; just like meat needs to be cooked, even insects could have some nasty bacteria in them. Unlikely but still possible.
I know you meant it as a joke, but eating insects is a great source of survival protein. Grasshoppers are easy to raise and can be blended to make “flour”. 😀
If I put my rice in food safe buckets and then put it outside when the temp is freezing or below for 2 days, what happens when I bring it back inside the house. Will the rice sweat and ruin the rice? And will heat kill the eggs. Say I put flour in food grade buckets, how hot would it need to get in my garage or on my porch to kill eggs? Also if I heat my flour in the oven to kill the eggs, how deep a pan should I use, oven temp and how long? I have 25 pound paper sacks, can I put the whole bag in the sack in the oven? Ii am looking for a way to kill tbe eggs before putting the flour into 5 gallon buckets without oxygen absorbers.
ALSO what happens when you move? Say you have flour, rice, beans in 5 gallon buckets and you go from hot to cold or cold to hot, do you have to worry about mold?
if your rice is in the buckets (hopefully with as little air space as possible), then freezing it is a good idea. moisture may condense on the outside of the sealed buckets as they are warmed. i’d go for longer/colder, though. bugs can survive ordinary freezing. the colder/longer the better. i’ve heard 10 days at deep-freeze temps. (but don’t quote me on that).
avoid heat. it takes a lot of heat to kill the bugs, and at those temperatures, the nutrition in the food is also being destroyed. a lot of people like to use bay leaves in the grain to deter bugs . . but i am not sure how effective that is long term; doesn’t hurt to try it though. might also look into food-grade diatomaceous earth.
if your product is sufficiently dry, you shouldn’t have to worry about mold.
it is best to avoid swings in temperature, and avoid higher temperatures in general, if you can. these will decrease the shelf life and the nutrition of the product. just do the best you can (that is different for everybody), and try to use and replace (rotate) your stock, to keep it as fresh as possible (and keep your body used to eating what you store).
keep up the good work!
I wrote a detailed post about pantry pests here: https://www.primalsurvivor.net/bugs-weevils-moths-food-storage/
It basically says what you wrote here. Though 10 days is a bit excessive for killing the eggs (the longest recommendation I found was 7 days and 3 days seems to work fine for me personally).
Thanks for the comments!
I’ve just purchased a 55lb bag of Caputo 00 Pizza flour. We’ve estimated that we’ll get through the 55lb bag over two years.
We live in Southern California, which can get quite hot during the summer, sometimes reaching 90° F indoors.
I like the idea of Mylar Bags + Oxygen Absorbers and was wondering if I need to keep the Mylar bags in an airtight container or not, or would I need to keep the Mylar bags in the freezer?
In saying all that, do I need to use Mylar bags at all, or would another method be more suitable seems as I don’t need to store it for 5+ years, and I will be using the flour on a weekly/bi-weekly basis?
Thank you in advance,
All you need to do is put the flour in sealed mylar bags with oxygen absorbers. There’s no need to put them in the freezer. I would avoid storing any whole-grain flours though in hot temperatures (the natural fats will start to go rancid). Some people do like to put their sealed mylar bags in buckets as protection against physical damage (earthquakes in CA!!). But that’s no really necessary.
In your case, maybe it makes sense to put some white flour in Mylar bags with O2 absorbers for emergency use. Keep the flour you use regularly in the freezer and rotate through it as needed.
I’m new here and new to food storage. I live in a dry climate (Nevada) and just bought some mylar bags to store my flour and rice. Do I really need to add oxygen absorbers? I would like to transfer the items to paper bags first and then the mylar bags and finally the 5gal food grade buckets. Thank You! Any advice is greatly appreciated.
The OAs are necessary for two main reasons:
-Insect eggs won’t hatch without oxygen. If you don’t use OAs, you’ll need to kill the insect eggs first. It’s an annoying process of freezing the food for about 5 days and then letting it come to room temperature. I’d rather use OAs! 🙂
-Oxidation makes food go bad. It might still be “safe” to eat, but it will lose vitamins. Fats will go rancif faster in the presence of oxygen.
In short, no. You don’t have to use them. But they are cheap and will make your food last much longer so you don’t have to rotate through it as quickly.
Hello there! I just came across your site, and you provided me with exactly the information I was looking for. Thank you. Where do you recommend purchasing Mylar bags and Oxygen Absorbers? TIA Lisa
There are some recommendations in these posts:
One of your options to storing flour is to vacuum seal the whole bag. Do I need to worry about bugs from the actual flour bags as some other peppers advise not to store with the bags to avoid bugs?
If there are bugs, they will be in the flour too (not just the bag). It won’t make a difference whether you remove the flour from the bag or not. To kill bugs and their eggs, you need to freeze or microwave the food and let it comem to room temperature before storing. See this – https://www.primalsurvivor.net/bugs-weevils-moths-food-storage/
How long do I need to microwave the flour? Should I do the same for rice, oatmeal and cornmeal?
See this post for info: https://www.primalsurvivor.net/bugs-weevils-moths-food-storage/ Be careful when microwaving cornmeal because it scorches easily. The same applies to corn pasta. You might need to stop the mmicrowaving and stir the products so heat spots don’t form in the middle.
What about storing dry cereal in mylar bags?
Dry cereal like Cheerios usually stores really well. Just make sure it isn’t something like granola that has tons of oil in it. That will start going rancid fairly soon.
Cheerios stored in Mylar bags, what kind of shelf life would they have?
Cheerios have very little fat in them, so they should last a very long time in Mylar. I can’t tell you for sure but I’d guess at least 5 years. The vitamin content would deplete over time, but this is true of any food.
your site is fantastic and you are a wealth of info…thank you!
is it the same for storing almond flour and coconut flour? mylar with O2? thanks very much!
Unfortunately, almond and coconut flour have a lot of natural oils in them. They will go bad fairly quickly (even in Mylar with O2 absorbers). Ideally, you should store whole almonds as there is less surface area and they will last longer. You can buy hand-crank mills for grinding almonds into flour during power outages. This post has info on how to store nuts in Mylar – https://www.primalsurvivor.net/mylar-bags-food-storage/ and here is more info on storing nuts specifically https://www.primalsurvivor.net/how-store-nuts/ . I don’t have much info (yet) on storing coconut flour though.
We were planning on putting our flour into kilner jars and storing them on our kitchen windowsill which doesn’t get direct sunlight. Would this make it spoil sooner? We will use heat to remove any insect eggs prior to storing
Yes, light will destroy certain vitamins in flour. But, honestly, the heat from baking is going to kill most of them anyway so I wouldn’t worry about that too much. So long as you rotate through the flour regularly, it should be fine on your windowsill.
Sadly I did not know to transfer flour from bag it comes in. Bought flour over a year ago, it has been in the same bag stored at room temperature. Does this mean the flour is not good? Should I just discard it? Don’t think I want to try to use it, purchased more and have mylar bags/oxygen absorbers to store it.
If it isn’t too humid, flour can last a really long time even without special storage. So, personally, if it didn’t taste sour or smell funky, I’d eat it even after a couple years. But I also feel like I need a legal disclaimer to do so at your own risk! 😀
i have keep flour in the freezer for almost 3 years with no problems. i have kept chocolate chips in the freezer for over 10 years and still good. have not tried the mylar bags. seems cheaper to use the freezer. keep one shelf just for flour, chips, rice and beans. was wanting to try oven canning some dry things. not sure. new someone who did it with nuts and worked out well.
Freezing is definitely the easiest option. But, as a prepper, I don’t like to rely on the freezer because of power outages. Plus, I don’t have enough space in my freezer so I only put perishables in there. 😀
What’s the ratio for flour to OA’s
Hey Diane. Thanks for this site, it’s really useful. I recently ran out of flour and opened up my storage bucket of white flour that has been in a food grade bucket with gasket, in a mylar bag with O2 absorbers, for 5 years. I was excited to see that the flour looked perfect. But when I baked a couple of loaves of bread with it, the bread baked up perfect, but it tasted weird. Almost metallic. I couldn’t eat it. Any ideas as to what might be wrong?
Did you add baking soda or baking powder to the bread? That tastes metallic when it goes bad. Otherwise, the flour shouldn’t taste metallic. Sometimes it gets a sour taste if the oils go rancid — but I’ve never heard of a metal taste.
So here’s my plan. I freeze the flour in its original package. I re-package in smaller zip lock bags, push out as much air as possible, then vacuum seal the smaller portions in food saver bags… Thoughts?
That would work. Just make sure you let the flour “sweat” out any moisture before repackaging. You also don’t want to seal the zip lock bag tightly or the vacuum sealer won’t be able to get the air inside.
Would instructions and shelf life be the same for coconut flour and almond flour?
Those flours actually don’t store well at all. They have too many fats and start to go rancid quickly. For almond flour, you are better off storing whole almonds and then grinding them when you need the flour. *Grinding up almonds increases the surface area, which means the food is exposed to more oxygen and degrades faster. Whole nuts last longer than nut flour.
See how to store nuts for the long term
I have been reading your answers to many questions; but I would like to verify please.
Leave flour in original bag, pull out after 3 days, let come to room temp, then add to Mylar bags, to the very top, throw in OA’s, seal the bags and place in container. Store in dark cool room until needed. Is that correct? If so, how many OA’s do you throw in?
Thank you so much. I’ve been looking for this kind of information and you are extremely honest and well versed with it all. Thank you again
Curious about this too; hoping to find the answer. I like the idea of putting in the freezer to kill bugs as an extra precaution but everything in my head says that if I put flour in the freezer it’ll get permanent moisture within it and I will have to use it right away once pull it out of the freezer ( I have the same concerns for rice, so any answers on that would be great too). Just to varify- can I put the flour in the freezer (original bag or something else recommended?), pull it out after X amount of time, let it “dry out” for several days, then put it in the mylar bag with OA, and expect it to be good for years to come(temperature permitting, of course).
am I wrong to worry about moisture from the freezer on something I’ll dry store later?
You do NOT need to freeze flour first if you will use oxygen absorbers. The eggs can’t survive without oxygen. Freezing rice/flour/etc is recommended if you will be vacuum sealing, putting in jars, or other packaging which hasn’t had the air removed from it.
Yes, that is correct. Just make sure that the flour doesn’t just some to room temperature but also “airs out” long enough in case any moisture pockets have formed.
As for OA amounts, read this: https://www.primalsurvivor.net/oxygen-absorbers/
I have several 1/2 gal mason jars (wide mouth) and was thinking about vacuum sealing white flour (has already been frozen for days). What would be the shelf life of doing that? Thank you.
I’d estimate at least 5 years (but can’t guarantee anything!). But you’ve got to check that the seal doesn’t break.
What Mylar bag and OA are you purchasing? Brand name please. All the reviews I see on Amazon is that their OA didn’t work and they’re made in China.
Unfortunately, almost all of the ones are made in China (like everything else we buy). You can see some links to recommended products in this post:
I put my flour in the freezer in the original bag. I intended to then take it out and package it. Have I just ruined all my flour or can I just bring it to room temperature and then package it?
You did not ruin your flour. 🙂 You can take it out of the freezer, let it come to room temperature AND make sure it has aired off (don’t want moisture pockets in it before packaging). Then you can package it for long-term storage.
I wouldn’t worry about the insects or their eggs… Just extra protein when you finally use the flour!
I bought a 5-lb bag of Pillsbury Best All-Purpose Flour today (March 8, 2022) and stamped on the bag is “Best If Used By 1/15/23”. So Pillsbury is telling me that their flour is still in good shape for at least 10 months.
With the exception of baby food and a few other products, there are no laws about “best by” dates. It’s up to the manufacturers to decide what date to put on the food. Flour will generally last much longer than 10 months (or even a few years) even without any special storage. For long-term storag though, it’s still best to put it in Mylar bags with oxygen absorbers. This method ensures that insects won’t infest the flour, keeps microbes from growing on it and prevents oxidition.
Can you repackage flour using brown lunch bags prior to vacuum sealing to freeze for storage. Also do you have to prefreeze before doing this? Our basement gets humid and think freezer would be safer than trying the Mylar bags. Also would you recommend removing boxed pasta from its packaging and vacuum sealing to better protect till use?
I don’t recommend vacuum sealing at all. Read this for more: https://www.primalsurvivor.net/mylar-bags-vs-vacuum-sealing
Can whole wheat flour be stored in mylar bags with oxygen absorbers? I am having difficulty finding information on this or do the same rules apply as regular all purpose white flour?
Yes, it can be stored in Mylar with OAs. The issue is that whole grains have lots of natural fats. These fats will go rancid even with OAs (particularly if stored in high temperatures). So, the shelf life of whole wheat flour is much shorter than for while flour stored the same way. More on shelf life here: https://www.primalsurvivor.net/oxygen-absorbers/
Can hand warmers be used instead of O2 absorbers when vacuum sealing
Never heard that one before! No, definitely not.
how do you store almond flour long term?
It’s really not suitable for long term storage. There are a lot of natural fats in almond flour and they will start to go rancid. Plus, because the nuts are broken down, the surface area is increased so oxidation happens faster. you are better off storing whole almonds and grinding them as needed into flour. Read this for more: https://www.primalsurvivor.net/how-store-nuts/
I keep reading that you need to keep some air in the bag for the flour to “breathe” – but obviously that will not work with the vacuum method.
Can anybody either confirm or provide more information? I am not sure if storing flour without any oxygen (ie, AO and mylar) is going to be OK?
I have never heard that advice. And it is definitely okay to store flour and other dry goods in Mylar with OAs. The key is that the product needs to be dry throughout or botulism can grow. Corn kernels and cornmeal, for example, are often quite wet and not always safe to store this way. More on that here: https://www.primalsurvivor.net/cornmeal-long-term-storage/
After mylar sealing flour with OA , can they be stored in regular plastic bins instead of food grade buckets in 72 degree or less room? Those buckets take up a lot of space.
I don’t see anything in here about vacuum sealed mason jars. Seems like that would be a good way to go. Any advice?
If the jars have an OA in them and are sealed properly, they would be good for long-term storage. But I personally don’t like storing food in jars because they break too easily.
I put my flour in the freezer before sealing it up in mylar bags with an oxygen absorber. The day I sealed it was a warm, really humid day and my windows were open. After sealing the bags, they got condensation on the outside where I guess the flour inside was still a little cooler than the outside air. My concern is whether or not there would be moisture inside the bags and that combined with the oxygen absorber making an environment for botulism to grow. Any thoughts on this? Thanks.
First off, you don’t need to freeze flour or other foods before storing if using OAs. Freezing is to kill insect eggs. But insect eggs can’t hatch without oxygen, so you don’t have to do it if using the OAs.
The condensation was probably because the flour was still cold. It should come to air temperature first so condensation pockets don’t form in the bag. Also, it’s always best to pack foods on low-humidity days or times of the day. I don’t know the specifics but botulism could be an issue. On the plus side, boutlism toxin is easily destroyed by cooking at 185 F 🙂 (the bacteria itself is heat-resistant but it doesn’t make you sick. It’s the toxin which makes you sick). Read this for more: https://ucanr.edu/sites/MFPOC/Emergency/Botulism/
Instead of tossing the flour, you could use it for baking something at over 185F. Next time, don’t freeze the flour.
How do you seal flour in Ziplock Mylar bags. I have some but can not get all the air out. Flour clogs up my Food Saver is why I bough these and now don’t know the correct way to put up flour. Thanks
For long term storage, you’ve got to use heat to seal the Mylar bags closed. The zip is kind of useless for long-term storage because air can get through, but it’s convenient for short-term storage.
Any ideas about storing almond flour? I bought a 3lb bag at Costco several years ago and just put it in the freezer in it’s original plastic ziplock seal type bag. it expired a year ago in 4/3/21, but I am still using it without problems tho I did have to break it up a little but I always get as much air out as possible when I close it. I just bought another 3lb bag and am wondering if there is a better way to store it. Since it is a nut flour, I am thinking it is more like cornmeal than regular flour? Comments appreciated
For long-term storage, I’d just buy whole almonds and store them. Then grind them into almond flour as you need it. Whole almonds last longer than flour because there is less surface area (thus less exposed to oxygen and starting to degrade). You also really need to keep fatty foods like nuts cool or they will go rancid. It’s still technically safe to eat rancid foods in that they won’t give you food poisoning, but they get a nasty taste.
Will flour be hard and look vacuum sealed when done? I did several bags of rice, oatmeal, pancake mix, instant potatoes, pinto beans the other day and beans and rice are rock hard but instant mashed potatoes and flour are still soft and don’t look vacuum sealed like other bags??
Forgot to mention I used mylar bags and oxygen absorbers.
It’s okay if the bags don’t look “sucked in”. OAs only remove oxygen and not nitrogen so the bags can still be soft. However, do check to make sure there aren’t any leaks in the seal. It’s really easy for bits of flour/powder to get into the seal area, preventing you from getting a good seal on the bags.
This is all very helpful to me as I am new to food preservation.
Could you verify this process with me? I buy a bag of flour, transfer it to a sanitized Mason jar, add OA to top of flour, secure lid and band on jar, wait until lid gets sucked in by the OA, place jar in cool dry place.
If this process is not correct, what did I miss? Are there any drawbacks to doing it this way?
That’s correct! The only drawbacks are that you can’t store too much in a mason jar and glass will break during earthquakes/hurricanes/etc. That’s why I prefer Mylar bags for long-term storage. But Mason jars are great for things which will stay in your pantry for a while until you rotate through them. After opening the mason jar, the OA will need to be replaced.
Love the site! Bread flour- can the same long term storage rule apply to it as it applies to all purpose flour(freezer or Mylar and OAs)? I love making bread. In a shtf, bread would be a treat and a filler.
Yes, the instructions for storing bread flour are the same as with all-purpose. The only one which has different instructions is self-rising flour because contains baking powder and/or baking soda.
Can self-rising flour be stored the same way? I’ve prepped all-purpose flour, but a friend wants to store the self-rising and I don’t know what to tell her. I assume it has baking powder or soda in it and as I understand, those should not be stored with oxygen absorbers. Thanks in advance for your insights.
She should just store regular flour and store leavening ingredients (baking soda, baking powder) separately. See these posts for how to store those:
If ziplock bags don’t seal perfectly because air leaks in at the zipper, then how are Mylar bags with zipper seals the best option? Won’t they leak air at the zipper too?
You have to seal the Mylar bags with an iron. The zipper is just for convenience. Also, ziplock bags actually contain tiny little holes in the plastic which slowly allow moisture and air inside. Mylar is completely impervious to air and moisture.
And how long can Mylar bags be reused?
It can be reused indefinitely. But each time you open a sealed bag, you have to cut off the sealed part. So the bag gets slightly smaller each time you open it.
What about aluminum heat sealed bags? Good or not?
Sorry, I don’t have any experience with those!
I have self rising flour I would like to store. Will the O2 absorbers not be recommended due to the extra ingredients in the flour? I know it’s not recommended for baking soda or salt, so… ? Thank you in advance!
It really isn’t recommended to store self-rising flour long-term. The leavening ingredients can get a really nasty taste to them. See this post: https://www.primalsurvivor.net/how-to-store-baking-soda/ Some people also say that OAs may interact with baking soda, but there is no actual reputable source for that claim and I personally haven’t tested it out. I’d just store it without OAs and make sure to rotate through it within a year or so.
I have tried sealing self raising flour in mylar bags with O2 absorbers and silica. They intially sealed well but after 6 months I checked and found they had expanded like balloons. I assume this is CO2 and might not affect biological growth but if left any longer it might pop the bags. I opened one and got a metallic smell from the bag- maybe some chemical reaction with the O2 absorbers- no good.
It’s the baking powder/leavening agents in the self-rising flour reacting with the iron in the OAs. It’s better to store leavening agents separately from your flour. More on that here: https://www.primalsurvivor.net/how-to-store-baking-soda/
Nothing here actually states that eggs are killed when using OA’s, it’s just said they can’t hatch.
I may be attributing miraculous powers to eggs (and they just might have them since I didn’t pay attention in high school biology), but for my own peace of mind and the fortune I’m spending on this (at least in my house it’s a fortune!) can someone confirm that eggs are killed using OA’s?
And for the record….yes, mom, you were right. I shoulda listened.
Oh, I forgot to add….I need to know about OA’s killing eggs because I literally have no way to freeze flour. Thanks!
I did some research. Yes, lack of oxygen kills eggs. The eggs are able to survive much longer than adults without oxygen though. So, if an egg managed to hatch in the packaging (unlikely but some insects are able to go into crazy dormant states where they can survive almost anything!), it would likely die within a few hours of hatching.
When you say store at cooler temperatures, how cool? Is 80 degrees too hot?
For whole-grain flour or other foods with lots of natural oils, then 80F is definitely too hot. The oils will go rancid. Ideally, you should keep foods below 70F (even better if you can keep them below 60F). But I realize that is almost impossible to do in many places. If you can, just really avoid storing food in the garage or attic. These places get crazy hot!
Just found your information, but trying to figure out how to comment was almost more difficult. I am freezing regular white flour first in their original bags. Will let them thaw out after and then remove the bags. However, I don’t want my flour directly touching the inside of the mylar bags. Can I just use brown paper bags for the flour and then put it into the mylar bag with oxgen absorbers? Or is that not possible or a good idea? I know I can use a vaccum sealer with a brown paper bag , but it won’t keep as long this way. Thank you for some great information.
However, I would never use a microwave for anything as it destroys many nutrients. Don’t own one anymore and never will again. They are also putting out a high emf field if you are close by. Just saying as I have researched this for years and have a meter.
1. You do not need to freeze flour first if you are using oxygen absorbers. Freezing is to kill insect eggs. But insect eggs can’t hatch if there is no oxygen, so there’s no need to freeze if you use O2 absorbers.
2. yes, you can put the flour into paper bags. Or just keep the flour in its original PAPER bag, put the entire bag into the mylar bag with O2 absorbers, and seal. If the flour is in plastic bags though, you need to remove it — the 02 absorbers might not be able to do their job if the flour is in plastic.
Where do I find a good source for fresh bulk flower? Have a suggested brand?
Ideally you would look up flour mills in your area. The prices will be a lot cheaper too. But that might not be an option if you live somewhere urban.
I don’t get why masaca will go bad if left in original packaging. I’ve never used it before but I bought mine in Sept the bag somehow opened, but when I checked it looks dry, clean white, bug free and smells like corn. Is it still bad since it expired in March? My kitchen is always hot so I keep it in the bottom cabinet’s.
Expiration dates aren’t federally regulated (other than baby formula). They are really “best by” dates. The oils in the food may have gone a bit rancid but, if it smells okay and tastes okay, then it should be fine to eat. Heck, I even eat flour which has bug infestations 😀
Hello. Today is the beginning of my long term storage journey. After watching many YouTube videos and reading through your webpage, I’m left a little confused about long-term storage for whole grain flours (other than all purpose). After watching Mary’s Nest (on YouTube) she suggests that the shelf life for whole grains ground into powder isn’t as long. Rather, she suggests storing the whole wheat berries, then use a mill to ground when needed. Are you familiar with this notion?
I am working on long-term storage for Gluten Free flour. I was thinking about doing the cooking method, just to kill off any eggs, store in the mylar bags with the OA. Do you think this will be sufficient for 5 to 10 year storage? GF Flour is expensive, but we have to use it for celiac in our home. Thank you!
You don’t have to freeze or cook grains to kill eggs if you will use OAs. Insect eggs can’t survive without oxygen.
Are my understandings correct?
If I put dry foods in a freezer for a few days all insect eggs will be killed forever.
But, If I put dry foods in an air tight container such as a glass jar with a tight fitting lid, with an Oxygen Absorber, the insect eggs will not hatch because they cannot hatch without oxygen. But, if you open the container to remove part of its contents, close it back up without adding a new Oxygen Absorber, then the insect eggs WILL BE ABLE TO HATCH!
You are correct on points 1 and 2 but not 3: If you open a container which had OAs in it, the eggs won’t hatch because they’ve died (not sure how long eggs need to be in an oxygen-free environment to die though…there’s not exactly a lot of research into this!). However, do note that each time you open a container with OAs, you let oxygen inside — the OAs are basically pointless at that point and the food will start to spoil because of oxidation. Basically, you need to add new OAs each time you open the container if you don’t plan on finishing the contents quickly.
I vacuum sealed 5 lb. Bags of flour, then put in freezer for a week..now I wonder if that was right, or will condensation/moisture be trapped inside bags Any suggestions? Thanks!
Unfortunately, you should have vacuum sealed it AFTER freezing. The flour needs to air out a bit so moisture pockets don’t form.
I stored my white flour in mylar bags with 2000 cc O2 absorbers, within a tight-lidded 5 gal bucket. It still went rancid after about 2 years of storage. I won’t be storing flour anymore. Hard red wheat lasts much longer; you just have to put in more work to prep it for consumption.
Are the steps for spring all purpose flour ok to apply when storing almond flour? I’ve picked up some almond flour but so far not put it to use so I’m looking for long term storage. I know storing nuts is a different process without using OA’s.
I don’t recommend storing almond flour. Because it is ground up, it has an increased surface area and will start to go bad faster. You are better off storing whole almonds and using a grinder to make flour if necessary. More on that here: https://www.primalsurvivor.net/how-store-nuts/
Morning, great ideas! New to prepping/long term storage so I have a few questions. If I have a food storage bucket filled with flour or rice, sugar, etc., how many OAs should be used…and do I just toss them in or position throughout?
Buckets *can* work for long-term food storage. But the seal on lids often starts to leak eventually, meaning that the OAs become useless. It’s better to use Mylar bags (and then put those bags in buckets to protect against rodents, physical damage, etc.).
Hello! Thanks for the good article.
I’m curious as to your thoughts on botulism for putting store-bought flour directly into a mylar bag with an OA. Claims vary, but 3-10% moisture content seems to be enough to allow botulism to grow. Flour – as I understand it – has more than that.
Nobody seems to think freeze-drying shelf flour is worth it (or necessary), but it seems to me this is in fact important if you are concerned about the toxin (as you should be). Thoughts on that?
Botulism needs approximately 35% moisture to grow. However, to play it safe, most sources recommend only using OAs with foods that have 10% or less moisture. I really don’t think freeze drying flour would be worth it. If you are really worried about botulism, you could just store the flour without OAs. You’d just have to take steps to kill insect eggs in the flour first (microwaving or freezing, for example).