Editor’s Note: This resource has been revised and updated for 2018!
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.
Survival Basics: Using Mylar Bags for Food Storage
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 mylar bags from Discount Mylar Bags.
They have a great selection for ordering in bulk and low prices.
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 1950s 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-grade buckets as well as food grade mylar foil. The bag is first placed in the bucket and then filled with the 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 mils 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
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:
For a more detailed and comprehensive handbook on food storage, be sure to check out my book, The Prepper’s Guide to Food Storage.
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!
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Bargain Bin: Here are some of my favorite food storage items. Whether you are just getting started or a seasoned pro, here are the items you will need when purchasing food in bulk for the long term, SHTF needs. And for help with your food storage questions, get Gaye’s 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 for very cheap.
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.
Ball Regular & Wide Mouth Jar Storage Caps: I must have 30 or 40 of these. I love to use mason jars for pantry 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 inexpensive FoodSaver will work just as well as the fancier models. That is my two cents, at least.
FoodSaver Wide-Mouth Jar Sealer: Already have a FoodSaver? If so, check out this jar sealer which can be used to vacuum seal your Mason jars. This is a great option for short to mid-term storage of items such as beans, rice, sugar, and salt. Store your jars in a cool, dark place and you are set with the added advantage of removing a small amount for current use without having to disrupt your large Mylar bag or bucket of food. There is also a version for regular sized jars. See Fast Track Tip #4: How to Use a FoodSaver for Vacuum Canning.
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: 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.