Survival Basics: Using Mylar Bags for Food Storage

Anyone who has been researching and studying food storage has undoubtedly heard the term “Mylar bag” mentioned relative to storing bulk foods.  As with the ubiquitous oxygen absorber, the mention of Mylar bags brings up as many questions as there are answers.  We have all heard that the best way to store dry goods for long-term storage is in a Mylar bag but how are they used?  So what exactly is a “Mylar bag”?  And what do you need to know to begin using Mylar bags? Here’s how to use Mylar bags for long-term food storage.

Everything you need to know to use Mylar bags for food storage |www.backdoorsurvival.com|

Best Mylar Bags to Buy

Before getting started, if you are just looking for the best quality mylar bags and the best possible price, I would highly recommend checking out Discount Mylar Bags here.

They have a great selection at an even better price.

What is a Mylar bag?

First and foremost, the term “Mylar” is actually one of many trade names for a polyester film called BoPet film.  For the technically inclined and the curious, that stands for “Biaxially-oriented polyethylene terephthalate”.  This film was developed by DuPont in the 1950’s and was first used by NASA for mylar blankets and long term storage as it increases the shelf life of food by eliminating oxygen. Think superpowered aluminum foil.

Since then, many uses for Mylar have been embraced due to its high tensile strength and its moisture, light, gas and aroma barrier properties.  Mylar is also a good insulator against electrical disturbances, which is why it is used for making emergency blankets.

For all of these reasons and more, Mylar bags are considered the gold standard when it comes to long-term food storage.

Mylar versus Metalized versus Dry-Pack Pouches

Do not be confused if your vendor of choice uses the term “Metallized Storage Bag” or “Dry-Pack Pouch” instead of Mylar.  This simply means that the bag is not using the Mylar-branded material.  As long as the bag is of food grade, and prevents exposure to air, you are okay. For all intents and purposes, Mylar to a metalized bag is as Kleenex is to facial tissues.

What Size Mylar Bag Should I Use?

The two most commonly used sizes for storing food products are the one gallon size Mylar bag (about 10” x 14”) and the five gallon size (about 20” x 30”).  Various other sizes are available but for starters, these are the two best sizes to have on hand.

The gallon bags are ideal for grains, dried powdered foods (like powdered milk), spices, hard candy, salts, and other baking ingredients. In addition, gallon bags are useful for protecting valuables including ammo and medical supplies.  When shopping for gallon sized bags, you should look for a minimum thickness of 3.5 to 4 mil.

The large, 5 gallon bags are typically used to line a 5 or 6 gallon plastic bucket. You will want to be sure to use food-gradue buckets as well as food grade mylar foil.  The bag is first placed in the bucket and then filled with product.  The bag is sealed before closing the bucket with a tight-fitting lid.

You might wonder why you should bother with mylar plastic if you’ll be using plastic buckets sealed with a lid. The combination of a Mylar bag inside a plastic bucket makes an unbeatable barrier against the woes and ravages of time, moisture, light and most important, rodents.  The bag alone will not keep out the rodents!  For that you will need a bucket. Glass jars or a mason jar can be used in a pinch, but these are much more susceptible to breakage than plastic.

Because of the weight of its contents, the thickness of a 5 gallon Mylar bag should be 4.5 mil or more.  And, just so you know, the thicker the bag, the tighter the weave of the polyester – that is what gives it its strength.  As a matter of fact, you will find bags that are 7 mil and even thicker but for most uses, 3.5 mil to 5 mil will work just fine.

Tips for Sealing a Mylar bag

Sealing a Mylar bag can be a challenge but with a little practice, you will find the process simple and efficient.  The easiest method is to use a hair straightening iron as a heat sealer to seal the top of the bag after it is filled with your dry, bulk foods and an oxygen absorber. Yes, you will want to throw in an oxygen absorber for an added layer of protection.

You can also use a vacuum sealer for sealing mylar bags. For more information on how to use mylar bags, I have created a detailed how-to for you in the article How to Seal Food in Mylar Bags.

Here are some additional tips.

Do not overfill the bag.  Remember that your oxygen absorber will suck out the oxygen, leaving only nitrogen in the extra space.

Only seal the top inch of your bag.  If you need to cut open the bag to remove product, you will have the space to seal the bag back up again.  Just don’t forget to add a fresh oxygen absorber. Try to avoid opening the bag too often, as repeated exposure to the air will impact your food’s shelf life.

If you are sealing up a powdery substance such as flour, be sure to wipe the inside edges first so that any residual dust is removed.  This will insure a good seal so no oxygen seeps through.

Check your newly sealed bags a few days after closing them up.  They do not have to be brick-like but they should be noticeably compressed.  If not, there is a likelihood that the seal was not good or a hole was poked in the Mylar.  Give it another week and if is still is not compressed, cut it open and start over.

When sealing pasta or noodles, feel free to seal them in their original packaging.  Cut a little hole in the package first, so that the oxygen absorber can do its job in removing every last bit of oxygen, even from the store packaging.

Check your sealer bags for damage before using. No memember of the prepper network should have to find out that their primary method of storing is compromised by holes that allow oxygen in.

Remember, heat is your enemy regardless of the packaging.  Store you packaged products below 85 degrees and preferably much lower than that.

What about Vacuum Sealed Bags?

Vacuum seal bags, such as those for the FoodSaver are a wonderful convenience and easy to use. But alas, they do not have the thickness nor the strength of Mylar bags and they may start to leak after 3 or 4 years. That said, they are still a great alternative for your short-term and mid-term storage items, especially if you are diligent about rotating foods and using them for your normal meal preparation activities. Just be sure to include an oxygen absorber if you plan to store your vacuum sealed bags for longer than a year. The combination of an oxygen absorber and vacuum make for a better long-term food storage option.

For tips on using a vacuum sealer for food storage, see  How to Use a FoodSaver for Vacuum Canning.

Note the Backdoor Survival “tranquilizers” in the jars waiting to be sealed!

Storing Filled Mylar Bags

For long-term storage, it is a good idea to store your filled Mylar bags in buckets or in a container.  Why?   Primarily to keep out bugs and rodents that can chew through the Mylar.  Also, as has happened to me, one of my 5 gallon Mylar bags split (accidentally) when I dragged a carton box over it. I had a 40 pound rice mess. It is funny now but it wasn’t at the time.

Where to Buy Mylar Bags

While you can always , for ordering in bulk I’d recommend visiting Discount Mylar Bags here.

For More Information

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

Survival Basics: What the Heck are Oxygen Absorbers?
16 Food Storage Tips for the Space Challenged Prepper
14 Common Food Storage Mistakes and Goofs

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

The Final Word

Packaging your own bulk foods for emergency use is a great way to save money.  Wal-Mart, Costco, and LDS Home Storage Centers sell bulk foods at reasonable prices and with a little bit of work on your part, can provide you and your family plenty to eat when the grocery store shelves are bare.

Not only that, the money you save will go a long way towards helping you fund the extra flashlights, water filters, and other items you need to keep you secure and safe when the stuff hits the fan.

Until next time, keep on prepping!

Enjoy your next adventure through common sense and thoughtful preparation!
Gaye

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

[related-posts]

Bargain Bin: Here are some of my favorite food storage items. Whether you are just getting started or a seasoned pro, here are the items you will need when purchasing food in bulk for long term, SHTF needs. And for help with your food storage questions, get my eBook: The Preppers Guide to Food Storage

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

10 Mylar Bags (5 Gallon Size):  Mylar bags can also be purchased in bulk without oxygen absorbers as can the one gallon size:  20 1-Gallon Mylar Bags.

60 – 300cc Oxygen Absorbers: This is one area where you want to make sure you are getting a quality product. Currently, a pack of 60 (in three 20 unit packs) is about $11 with free shipping.

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

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

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

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

Mylar Zip Seal Food Storage Bags The Sunday Survival Buzz Volume 22: These are the zip seal bags that I used to package up my spices, herbs and butter powder. These are extra heavy, 5 mil bags. I found that the zip feature made packaging extra easy although I still seal the bags with my hair iron.

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  1. Love your blog. Today you talked about LDS Home Storage Centers and buying in bulk. Can anyone purchase from the LDS Center or is it only for the LDS? We are trying to build up our food and if we could go to them which is close by we would do so. Thank you for all you do to educate all of us.

    1. LDS Home Centers are open to the public but I always suggest calling first because sometimes the hours or days of the week they are open are limited. Their prices are fanstastic; you can go to their website and download a price list in advance.

  2. I always find useful information on your site.

    I do have one question. I live in Alaska, and indoor warm storage is a luxury that I do not currently have. Do you know what the temperature rating is for Mylar bags? I have not been able to find any information about how they handle in prolonged temperatures of -20 to -50 F.

    Any information you can give me would be greatly appreciated.

    1. James – I wish I could give you a definitive answer based on my own experience but can not. I am traveling this week but when I get home, I plan to put a filled Mylar bag in my freezer (a warm -2 degrees) to see what happens over the next few months. I know that is not the answer you wanted but I will see if I can call one of the manufacturers and get a more definitive answer for you.

  3. I have learned so much from you Gaye! I swear that I had no clue about mylar bags or oxygen absorbers until I started reading your articles and now I actually feel like…”I can do this.” thanks for the info and for thoughtfully presenting in an easily understandable way. On a side note… I’ve been reading the TPR5 and congrats on being included with some other good authors.

  4. overall a very good article …. but a couple of things

    you mention leaving pasta in the retail shelf packaging … no …. never ever …. the only thing that goes normally is the food … never retail packing materials … just loaded with contamination – especially with materials that will off gas toxic chems …

  5. Just read your article about using mylar bags. Can they sealed using something like the foodsaver vacuum sealer. If I already have one, it would be easier than using a hair iron.

    1. Not really. The FoodSaver does not get hot enough to create a lasting seal.

      Some folks use a hose extension to suck the air out of the Mylar bag then follow-up by sealing the Mylar bag with an iron (clothes iron or hair iron) but I feel that is an extra step since an O2 absorber will do the same thing.

      BTW, I used to do the “suck the air out first” rigmarole myself but now I do not bother.

  6. I don’t have a hair iron, so I use a metal level and a regular iron. Place your level on it’s side (just like you would to when using it for checking levels) so the edge provides a flat surface to seal on, and place the open end of the mylar bag where you want the seal across the flat edge of the level, and run the iron across the bag, but leave an inch or so open on one end. Use that hole to squeeze out as much extra air as possible, pushing down on the bag and contents, squeezing toward the hole, then make the final seal.

    Question about flour. I seem to recall from another article that processed flour is not the best thing to store long term. That it’s better to store whole grains, then grind your own flour? Can you expand on that. Or is it OK to store flour?

    1. The context of what you have read may have to do with storing pre-ground whole wheat flour versus white flour. Just like brown rice, if storage conditions are not optimal (i.e. too hot), the oils in the whole wheat flour will turn rancid over time. This has never happened to me; I am still using stored whole wheat flour that was packaged in Mylar with an O2 absorber 4 years ago. My storage area, however, is under 70 degrees year round.

      Storing pre-ground white flour should not be a problem at all as long as it is properly packaged and sealed.

      With any flour, one of the bigger risks comes from pests such a weevils. I have never done it but I am told the freezing flour before packaging for the long term will kill the eggs as will adding a few bay leaves to the package before sealing it up.

    1. Depending on what you are storing, you will want to remove the packaging and store the product in either a Mylar bag, Bucket, or Mason Jar. Each should have an O2 absorber added.

      I am not sure this answers your question. Are you referring to packaged foods from the grocery store or food that is already factory sealed and good for 20+ years? In the case of the latter, the best advice I have is to store your food in a cool (under 70 degrees, preferably lower) location that is dry and immune from temperature fluctuations.

  7. Thank you! Love your blog. Wondering if you have a list of foods and how long they will stay good for in mylar bags. I don’t want to have to go thru the rotation date thing! It would be a huge help if someone had one.

    1. Since I am fairly relaxed about the shelf life of my food storage, it would be hypocritical for me to quote some hard and fast rules. With the exception of rancid-prone food items (brown rice comes to mind), it is my opinion (stress opinion) that properly sealed Mylar bags with a O2 absorber will be fine for 10 plus years. This assumes storage in a temperature stable environment of 70 degrees or less.

      When opening any food item, whether self packaged or manufactured, I use the sniff test. If it smells bad, it gets dumped. Or, of course, if the packaging has been broken or is bulged or leaking (which can happen with canned goods).

      Do not let the fear-mongers tell you that food that is 5 years old needs to be dumped. I simply do not believe it.

  8. Gaye,
    While I applaud you for the correct discription that MYLAR is Bopet. However other parts of your discription are incorrect. See correction below. This is my stock reply to posts about MYLAR. Mylar is a clear plastic. That silver shine is the aluminum the PET&LLDPE are laminated to.

    Mylar Bags
    Correction: Why do folks who post articles about food storage continue to call those shinny silver bags MYLAR BAGS? There is not one iota of Mylar in any of those bags.
    Mylar is the trade name for BoPET or (biaxially-oriented polyethylene terephthalate).
    How Mylar is made: Molten polyethylene terephthalate (PET) is extruded as a thin film onto a chilled surface, such as a roller.The film is drawn biaxially. Special machinery may be used to draw the film in both directions at once. More commonly, the film is drawn first in one direction and then in the transverse (orthogonal) direction. Heated rollers are effective for achieving this.
    Finally, the film is heat set by holding it under tension above 200 °C (392 °F).
    The heat setting process is what gives BoPET its strength and heat shrinkage resistence. Think MRE’s and lids on TV Dinners and other plastic packaging that goes in the microwave or oven.
    A pure film is so smooth it sticks to itself when rolled, so inorganic particles may be embedded in the surface.
    What you have in those shinny silver bags is PET and LLDPE laminated to aluminum foil. Ask for the manufactures material spec sheet. Where’s the BoPET? The cost would be nearly double if the bag material was laminated BoPET, Alum, LLDPE.
    The reason for the three ply 5mm+ bag is to reduce liquid, air/vapor, and light transmission to reduce spoilage and gives the bag added strength,that is what the alum foil is for. The PET& LLDPE by themselves are very porous and shrink from heat. Larger heavy duty four ply 6mm+ bags have nylon (Ny) incorporated in the bag.
    Homesteaders, Preppers & Survivalists Do Your Homework, Educate yourself.

  9. I already put food in food saver bags. Can I put each bag into a.
    Mylar bag now and which are the best ones? My first attempt at this.I am grateful for any help

    1. There are many ways to answer your question. The first is how long do you plan to store the food that is already in Foodsaver bags? If the answer is 2 or 3 years, leave them be and use them within that period. If longer, I suggest putting the individual bags in a bucket, adding a 1000 or 2000 cc oxygen absorber to the bucket itself, then sealing up the bucket with a lid or gamma seal. That way you will not have to re-bag the food products products.

      Mylar bags are stronger than FoodSaver bags and do not let light or moisture in. As far as the best ones, some are thicker than others. 3.5 mil is a good starting point for smaller bags (1 gallon or less). Due to the weight factor, you will want 4.5 mil or better for the 5 gallon Mylar bags.

      BTW, I have a Mylar bag review coming up on Friday so you might want to watch for it. There will be a great giveaway as well.

  10. yes I would like to know how to figure out what size of oxygen absorber to use when you start sealing bags of food or buckets of food

  11. I put brown sugar in mylar bags and put in a oxygen absorber was this a mistake? Should I open them and remove the absorber?

  12. I have some big 55 food grade metal barrels that i was going to just put my flour, rice, oats, etc each in and leave in the bag it came in and just rotate through it (got the idea from deals 2 meals) the bins have metal lids and should be rodent resist but i’m worried now about bags being ripped during handling (already has happened), weevils, pantry bugs, or not going through it fast enough and it going rancid. Do you think i would be ok to divide my flour up into mylar bags with oxygen absorber’s and just put/stack right into the 55 gallon barrel? Do mylar bags need there own bucket each?

    1. Dividing your dry goods into smaller packages by placing in Mylar bags with an O2 absorber is an excellent strategy. You can mix and match Mylar bags in a single container; they do not need to be alike.

      One other thing if you are concerned with bugs. Consider freezing your dry goods for a few days before packaging for the long term. This should kill the eggs.

  13. i just bought my first mylar bags, they came folded and when held up to the light, you could see what looked like little holes.i had read somewhere that this means your bags will not seal, I emailed them and they said they aren’t holes. Is this correct and will they work properly?

  14. Foods like individual microwave packets of instant oatmeal with bits of raisins, dates and nuts in them…should I empty their contents into mylar bags or can I just slip them into mylar bags in their original packets? Should I use oxygen absorbers, too? I didn’t know because of the raisins. Thank you.

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